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(Health) Exercise and Health: Motivate Children to Exercise
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PostPosted: Wed Dec 28, 2005 11:38 am    Post subject: (Health) Exercise and Health: Motivate Children to Exercise Reply with quote






Motivate children to exercise
Tehran Times
December 28, 2005

Studies have shown an alarming increase in obesity in children. Encouraging children to exercise is the best way to prevent excessive weight gain and to keep them healthy.

You can begin by setting a good example yourself. It is hard to persuade your child to play outside instead of watching television, if you spend most of your own leisure time in front of the set.

Investing in bikes and going on regular family bike rides can be a great exercise plan. Taking your children on walks to the stores and walking with them to school rather than using the car are also good ways to establish positive habits.

Encourage children in any aptitude they may show for a particular sport and work around problems that may prevent them from taking part. For example, an asthmatic child may have difficulty breathing while exercising, but increased fitness can actually improve asthma.

In consultation with your doctor, a suitable routine can be developed. Swimming has been shown to cause exercise-induced asthma less often than other sports, and because children love playing in water, it's a great way to introduce them to exercise.

Increasing your child’s fitness outside of school may also help him feel more confident about joining in school sports and other activities.

Making exercise fun is the best way to encourage it. If your children feel intimidated by the pressure of team sports, explore other exercise options with them. For example, orienteering, in which children learn map-reading skills while hiking, may suit a more introverted youngster.

Encourage young people to participate in exercises that are appropriate for their ages.

During early childhood the focus should be on fun games and activities that develop the basic movement skills of running, balancing, jumping, kicking, and throwing. Between the ages of 6 and 12, more emphasis can be given to areas where a child shows a particular talent.

*************************************************************

Questions to explore further this topic:

Why is exercise important?

http://www.americanheart.org/p.....ifier=4596
http://kidshealth.org/parent/n.....rcise.html
http://www.nlm.nih.gov/medline.....28545.html
http://www.kidsource.com/kidso.....phyed.html

What does exercise do?

http://www.girlpower.gov/girla.....hybody.htm
http://kidshealth.org/kid/stay.....t_out.html

What are suggested activities for kids?

http://www.girlpower.gov/girla.....itness.htm
http://www.mayoclinic.com/health/fitness/FL00030
http://kidshealth.org/parent/n.....ining.html
http://www.kidsrunning.com/ask/krask0331phys.html

There are no computer games for this one,
Just Go Out and Play


Last edited by adedios on Sat Jan 27, 2007 4:38 pm; edited 2 times in total
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PostPosted: Fri Dec 30, 2005 10:55 am    Post subject: Poor Fitness Common In Teens And Adults Reply with quote

Source: JAMA and Archives Journals
Date: 2005-12-28
URL: http://www.sciencedaily.com/re.....180437.htm

--------------------------------------------------------------------------------

Poor Fitness Common In Teens And Adults, With Associated Rise In Cardiovascular Disease Risk Factors

Approximately one-third of adolescents and 14 percent of adults (aged 20 to 49 years) in the U.S. have poor cardiorespiratory fitness, with an associated increased prevalence of cardiovascular disease risk factors such as higher total cholesterol and blood pressure levels, according to a study in the December 21 issue of JAMA.

There is strong and consistent evidence from observational studies that physical inactivity and poor cardiorespiratory fitness (i.e., fitness) are associated with higher illness and death from all causes, including cardiovascular disease (CVD) and cancer, according to background information in the article. United States population reports describe an increasingly less physically active society, with marked downturns in reported physical activity during adolescence and young adulthood. Prior to the current National Health and Nutrition Examination Survey (NHANES), data were not available to quantify objectively determined cardiorespiratory fitness in the U.S. population. The extent to which physical inactivity affects the risk of heart disease through its negative impact on cardiorespiratory fitness, which is associated with a high prevalence of other CVD risk factors, is not known at the population level.

Mercedes R. Carnethon, Ph.D., and colleagues from the Feinberg School of Medicine, Northwestern University, Chicago, examined the prevalence of low fitness in the U.S. population of adolescents and adults younger than 50 years and determined the relation between low fitness and CVD risk factors in this population. Using data from NHANES 1999-2002, the researchers analyzed data for adolescents (aged 12-19 years; n = 3,110) and adults (aged 20-49 years; n = 2,205) who were free from previously diagnosed CVD. The participants underwent submaximal graded exercise treadmill testing to achieve at least 75 percent to 90 percent of their age-predicted maximum heart rate. Maximal oxygen consumption (Vo2max) was estimated by measuring the heart rate response to reference levels of submaximal work.

The researchers found that 19.2 percent of the surveyed population--an estimated 16 million U.S. adolescents and adults younger than 50 years--were in the low fitness category, and 33.6 percent of adolescents (approximately 7.5 million) and 13.9 percent of adults (approximately 8.5 million) had low fitness. Among adolescents, the prevalence of low fitness was similar between females (34.4 percent) and males (32.9 percent), but among adults the prevalence of low fitness was significantly higher in females (16.2 percent) compared with males (11.8 percent). Non-Hispanic blacks and Mexican Americans were less fit than non-Hispanic whites. Body mass index and waist circumference demonstrated the most consistent inverse associations with fitness. Total cholesterol levels and systolic blood pressure were higher and levels of high-density lipoprotein cholesterol were lower among participants with low vs. high fitness.

The researchers add that because older adults and individuals with existing risk factors for CVD were not tested on the treadmill because of possible health risks, the results of this study likely underestimate the true prevalence of low fitness in the population.

" ... this report indicates that low fitness is a prevalent and important public health problem in the U.S. population. The consequences of declines in physical activity over time are now evident by the large proportion of society with low levels of fitness. The correlations we report between low fitness and CVD risk factors suggest a potential trend of increasing morbidity and mortality from chronic diseases--the first sign of which is the burgeoning obesity epidemic. Historical evidence from the campaign to educate about the dangers of cigarette smoking indicates that education efforts, particularly among youth, can retard and reverse these negative health behaviors. Thus, it is plausible that a similar education campaign about the health benefits of physical activity to improve cardiorespiratory fitness, in combination with changes in health care policy to make environments more conducive to physical activity, could begin to reverse this serious public health problem," the authors conclude.



###
(JAMA.2005; 294:2981-2988. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: Financial support for data collection was provided by the National Center for Health Statistics (NCHS), a part of the Centers for Disease Control and Prevention, Department of Health and Human Services. Dr. Carnethon was supported in part by a career development award from the National Heart, Lung, and Blood Institute, National Institutes of Health.
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PostPosted: Mon Mar 06, 2006 4:16 pm    Post subject: The Harder You Exercise, the Quicker You Recover Reply with quote

The Harder You Exercise, the Quicker You Recover
By Bjorn Carey
LiveScience Staff Writer
posted: 06 March 2006
03:35 pm ET

New research suggests our bodies bounce back from a tough workout more quickly than we might think.

Training often and hard seems to be the key.

Researchers studied the exercise regimens and recovery times of 25 men competing in an Ironman triathlon, a three-part race consisting of a 2.4-mile swim, a 112-mile bicycle leg, and a 26.2-mile marathon run.

Although this competition is much more taxing than your standard cardio kickboxing class, researchers were surprised to see how quickly the athletes' bodies recovered. It takes about two week for muscles and tendons to fuly recover after an Ironman triathlon.

But one day after the race the competitors' heart rates, cardiac output, and blood pressures had returned to baseline levels. Within three days, other system changes brought on by activity also reverted to normal.

Blood flow is controlled mainly by the autonomic nervous system, which consists of two subsystems. The sympathetic nervous system accelerates heart rate, constricts blood vessels, and raises blood pressure. The parasympathetic nervous system reverses these effects.

While well-trained athletes generally have increased parasympathetic tone at rest, researchers expected sympathetic effects to last well after a triathlon. However, the fastest finishers, who also trained the most, also maintained a relatively low level of sympathetic tone.

"The low level of sympathetic tone also contributes to the fast recovery time," said David Spierer, director of the Human Performance Laboratory at Long Island University. "These physiological findings are very interesting and could significantly impact training of athletes in the future."

This research, announced today, was detailed in the Journal of Applied Physiology.
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PostPosted: Wed Apr 26, 2006 1:31 pm    Post subject: Study may explain why exercise helps heart failure patients Reply with quote

American College of Cardiology
26 April 2006

Study may explain why exercise helps heart failure patients

Training program may reverse underlying abnormalities more effectively than drug treatment
(BETHESDA, MD) – Aerobic training is associated with a reversal of abnormal hormonal patterns that underlie many of the debilitating symptoms of heart failure, according to a new study in the May 2, 2006, issue of the Journal of the American College of Cardiology.
"A feasible home-based and progressively adjusted aerobic training strategy is able to overcome the limitation of pharmacological treatment in antagonizing neurohormonal activation in heart failure patients, likely contributing to a significant improvement in quality of life, and possibly to the positive prognostic effects," said Claudio Passino, M.D. from the CNR Institute of Clinical Physiology in Pisa, Italy.

It is well-known that exercise training helps many heart failure patients feel better and improves their ability to function more normally. This study indicates that aerobic training may produce these benefits by reversing the abnormal production of certain neurohormones that result in many of the severe symptoms of heart failure.

After a heart attack or other cardiac event, the body responds by increasing the production of B-type natriuretic peptide (BNP). This neurohormonal activation, as it is called, helps the heart continue to pump blood in the short run by constricting blood vessel and retaining sodium in cardiac cells.

"This neurohormonal imbalance becomes detrimental on the long-term, promoting left ventricular fibrosis, dilatation, arrhythmias, peripheral tissue hypoperfusion, edemas, and thus leading to a symptomatic disease with dyspnea and fatigue," Dr. Passino said.

Previous studies indicated that patients with higher levels of B-type natriuretic peptide have poorer prognoses. Drug treatments are often unable to adequately reverse the neurohormonal activation.

Since physical activity often helps heart failure patients, the researchers wanted to find out what effect aerobic training has on the neurohormonal imbalance. They randomized heart failure patients into two groups. The treatment group consisted of 47 patients who entered a nine-month aerobic training program that progressively increased the amount of work the patients were able to perform. The control group of 48 patients received standard heart failure treatments, but no physical training.

The 44 patients who completed the training program improved their fitness and said their quality of life was better than the 41 patients who completed the control group arm of the study. But in addition, the patients who worked out had decreased levels of three key hormones, B-type natriuretic peptide (BNP), amino-terminal pro-brain natriuretic peptide (NT-proBNP), and norepinephrine.

Dr. Passino said the results indicate that aerobic training may be able to restore neurohormonal balance in a way that may improve on current drug therapies.

"Reversing neurohormonal activation by physical training adds to the current clinical practice a novel non-pharmacological aid. Out of 85 patients who completed the protocol, only the 44 randomized to the training program improved functional capacity, systolic function, and quality of life, in contrast to the controls. These beneficial effects were associated with a decrease in plasma level of BNP, NT-proBNP, and norepinephrine, only in the training group," he said.

In addition, he said that the measurements of neurohormonal activation used in this study may be a useful way for physicians to assess the effect of training in their patients.

John Floras, M.D., D.Phil., F.R.C.P.C. from the University of Toronto in Canada, who was not connected with this study, said the results provide additional evidence of the benefits of exercise for selected heart failure patients, while offering fresh insight into how training works to provide those benefits.

"While an acute bout of exercise will lead to increases in both norepinephrine and BNP, with chronic training plasma concentrations of these factors diminish, suggesting that exercise training modulates beneficially activation of several neurohumoral pathways that reflect the severity of heart failure, and that following BNP concentrations may be one way of assuring that long term exercise training programs are having beneficial effects in individual patients. Pending is evidence from large randomized clinical trials that such short term changes will translate, over time, into mortality benefits for patients with chronic heart failure," Dr. Floras said.


###
Disclosure Box

Sources quoted in this news release do not report any potential conflicts of interest regarding this topic.
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PostPosted: Wed May 10, 2006 7:31 am    Post subject: Exercise can protect against skin cancer Reply with quote

Rutgers, the State University of New Jersey
9 May 2006

Exercise can protect against skin cancer

NEW BRUNSWICK/PISCATAWAY, N.J. – While doctors and scientists have long agreed that physical activity has health benefits, Rutgers cancer researcher Allan Conney and his New Jersey colleagues have found that exercise can even protect against skin cancer.
Their study, reported in the May 13 issue of the journal Carcinogenesis, found that mice exposed to ultraviolet B light (UVB) – and with continual access to running wheels – took longer to develop skin tumors and developed fewer and smaller tumors than a group of similarly exposed mice that didn't have a gym handy.

This is the first time the relationship between skin carcinogenesis and increased activity by voluntary running wheel exercise has been studied in the laboratory.

In both groups, the number of tumors per mouse increased with time, but animals with access to running wheels had approximately 32 percent fewer tumors than animals without running wheels. Tumor size per mouse in the non-exercising group was on average more than three times greater than for the group with the running wheels.

As might be expected, the exercising mice ate and drank more but had less body fat than their more sedentary associates, and the number of tumors also decreased with lower body fat.

"This relationship between body fat and tumors may also play an important role in carcinogenesis and warrants further investigation, particularly with obesity on the increase in the Western world," said Conney, State of New Jersey Professor of Chemical Biology at Rutgers, The State University of New Jersey.

In another first, the researchers also detected what could be the mechanism responsible for this effect. Subsequent to the studies reported in the journal article, they conducted follow-up work that suggests that exercise enhances UVB-induced apoptosis (programmed cell death) both in the skin – a normal, protective process that removes sun-damaged cells – and in UVB-induced tumors.

"While UVB is triggering the development of tumors, exercise is counteracting the effect by stimulating the death of the developing cancer cells," said Conney, who is also the director of the Susan Lehman Cullman Laboratory for Cancer Research at Rutgers' Ernest Mario School of Pharmacy.

Conney noted that all these conclusions are based on laboratory studies on mice, and it is not yet known whether exercise decreases the risk of sunlight-induced skin cancer in humans. Clinical trials are needed to investigate this further. In bowel cancer, however, evidence from population studies already suggests that physically active people have a reduced risk of developing the disease, but the mechanisms remain unclear.
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PostPosted: Sun May 28, 2006 12:28 pm    Post subject: Outrunning Melanoma Reply with quote

Outrunning Melanoma

Exercise may prevent skin cancer.

By Victor Limjoco

May 25, 2006 | Biology & Medicine


Researchers found that exercising mice had fewer skin tumors after being exposed to UV light.

As we head to the beach this summer, we know we should bring along some sunscreen.

But now researchers say that a good dose of exercise might also help protect you from skin cancer.

Rutgers University cancer researcher Allan Conney found that hairless mice that work out get fewer skin tumors when exposed to ultraviolet rays.

As he reported in the journal "Carcinogenesis," mice with running wheels in their cages had 32 percent fewer UV-induced tumors than mice without running wheels. "You shine UV light on them, they had fewer skin tumors than the animals without runwheels," Conney says. "Voluntary exercise inhibited UV light-induced skin cancer."

Exercise even prevented tumors in mice that had already been exposed for long periods to UV light. "This could be similar to people that are heavily exposed when they're children out on the beach a lot and later in life they're not exposed to as much sunlight," Conney says.

"The mice love to go on the runwheel, sometimes two or three of them at a time," Conney says. Some mice ran up to three miles a day. While these exercising mice ate more, they weighed the same at the end of the study and had less body fat than the sedentary mice.

Conney thinks that decrease in body fat may be important in this protective mechanism. "Those mice, even in the exercising group, that had lower amounts of fat had fewer tumors," he says.

He also found that the exercising mice seemed better able to destroy skin cells damaged by the sun. When cells are injured, they die to prevent further damage. "The sunlight causes DNA damage in the cell, and the body has a way to eliminate those cells from the body by a process called apoptosis, " Conney explains. That beneficial process of "cell suicide" was sped up in the skin of exercising mice.

While sunscreen is still key to preventing skin cancer, Conney thinks if a controlled study were done in people, his findings in exercising mice would hold true for us. But he notes that forced exercise might not have the benefits of voluntary exercise. "So it raises a question," he says. "If one's wife tells you to go exercise, is that forced exercise or voluntary exercise?"

To see video of this story, please visit our partner, www.ScienCentral.com

http://www.sciencentral.com/ar.....=218392796
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PostPosted: Sun Jul 23, 2006 10:57 am    Post subject: Study: Kids Should Play More Reply with quote

Study: Kids Should Play More

By Maria Cheng
Associated Press
posted: 21 July 2006
11:59 am ET

LONDON (AP) -- Doctors may soon have a prescription for health that even kids will like: more playtime. European and international health experts say a new study makes the most convincing case yet for the benefits of children being active. They say the research may lead to new guidelines saying youngsters between ages 5 and 16 need to be active up to 1 1/2 hours a day.

For the full article:

http://www.livescience.com/hum.....ytime.html
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PostPosted: Thu Aug 03, 2006 10:33 am    Post subject: Protein-added sports drinks don't boost performance Reply with quote

McMaster University
3 August 2006

Protein-added sports drinks don't boost performance during exercise, study finds

Hamilton, ON. August 3, 2006 -- Adding protein to a sports drink won't make you race faster, suggests findings from researchers at McMaster University.

"Sports drinks improve performance during prolonged exercise because of two key ingredients: carbohydrate, which provides fuel for working muscles, and sodium, which helps to maintain fluid balance," says Martin Gibala, an associate professor of kinesiology at McMaster. "Research also supports the practice of consuming protein after exercise to promote muscle recovery. However, the alleged benefit of consuming protein during exercise is controversial."

The study, which is published in the August edition of Medicine & Science in Sports & Exercise, found that adding protein to a carbohydrate-electrolyte sports drink did not improve cycling time trial performance compared to the sports drink alone.

The research was conducted on 10 trained cyclists who performed a simulated 80 km bicycle race on three occasions. During exercise, the subjects were given a sports drink, a sports drink supplemented with protein, or a placebo drink that provided no energy. The drinks were similarly flavored and neither the subjects nor the researchers knew what drink was consumed during a given test. The study found that the sports drink improved performance compared to the placebo drink -- confirming prior research -- but there was no additional benefit of protein supplementation.

"Previous studies that suggested protein was beneficial used 'ride to exhaustion' tests that do not resemble normal athletic competition. In addition, the subjects in those studies received less than the optimal recommended amount of carbohydrate," says Gibala. "Our study shows that protein confers no performance benefit during 'real life' exercise when athletes consume sufficient amounts of a sports drink."

The study, which was funded by Gatorade, comes at a time when the sports drink industry is under pressure to create new products by adding ingredients that might further enhance performance. Some companies have heavily marketed protein-laced sports drinks as the next magic bullet, but Gibala's research disputes such claims.

"Eating a little protein after exercise is important to help repair damaged muscles and promote training adaptations," says Gibala, "but no compelling evidence suggests that endurance athletes need protein during exercise."


###
McMaster University, a world-renowned, research-intensive university, fosters a culture of innovation, and a commitment to discovery and learning in teaching, research and scholarship. Based in Hamilton, the University, one of only four Canadian universities to be listed on the Top 100 universities in the world, has a student population of more than 23,000, and an alumni population of more than 115,000 in 128 countries.
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PostPosted: Fri Aug 04, 2006 7:24 am    Post subject: more vigorous exercise equals better academic performance Reply with quote

Michigan State research finds more vigorous exercise equals better academic performance

Michigan State University
Aug. 3, 2006

EAST LANSING, Mich. – Middle school students who perform more vigorous physical activity than their more sedentary counterparts tend to do better in school, according to a study published today by researchers from Michigan State University and Grand Valley State University.


The research is published in the August issue of Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine.


For one academic year, the study tracked more than 200 sixth graders. For one semester half of the students took the general physical education class offered by the school, while the other half took part in a non-physical education course. Halfway through the school year they switched.


The researchers found that students taking the physical education course did no better or worse in their academic classes.


However, they also found that students who took part in more vigorous physical activities – such as organized sports like soccer or football, or non-organized after-school activities such as skateboarding – did approximately 10 percent better in core classes such as math, science, English and social studies.


“We have precious few studies that link activity or fitness to measurable academic outcomes,” said Jim Pivarnik, an MSU professor with appointments in kinesiology, epidemiology, and physical medicine and rehabilitation who is one of the study’s co-authors. “Considering all the factors that go into what determines students’ grades in school, a 10 percent increase by the most physically active kids is huge.”


It’s long been speculated that fitness and improved academic performance go hand in hand, said Dawn Podulka Coe, the study’s lead author who was a Michigan State University doctoral student when she led the project.


“Physical education and activity during the school day reduce boredom and help keep kids’ attention in the classroom,” said Coe, who is now an assistant professor in the Department of Movement Science at Grand Valley State University. “We were expecting to find that students enrolled in PE would have better grades because of the opportunity to be active during the school day. But enrollment in PE alone did not influence grades.


“The students who performed better academically in this study were the most active, meaning those who participated in a sport or other vigorous activity at least three times a week.”


It’s important to note, said Pivarnik, that the grades of the students taking the physical education course did not change for either the good or the bad. This is noteworthy because in this day of “No Child Left Behind” and standardized testing, many public school boards think physical education is a luxury they just can’t afford.


“If kids have PE every day, is it going to hurt grades? The answer is no,” Pivarnik said. “But, maybe if we pump up the volume a little bit, if they are a little more vigorously active, it might make a difference.”


The difference between vigorous activity and moderate activity is heart rate. Moderate activities, such as walking or raking leaves, don’t get the heart rate up or make the person breathe harder.


Vigorous activities, such as running or swimming for exercise, increase heart rate, causing the exerciser to breathe harder.


The fitness levels aspired to in this project are derived from federal government guidelines for health-related behaviors known as “Healthy People 2010.” Developed from these guidelines, which range from limiting alcohol use to wearing seatbelts to avoiding violent behavior, was a list of leading health indicators that can be targeted for change.


“No. 1 on the list: physical activity; No. 2: obesity,” Pivarnik said. “These are highest on the list because they are modifiable and they are related to so many diseases.”


Other participants in this study were Mathew Reeves, an associate professor in MSU’s Department of Epidemiology, and former MSU kinesiology faculty members Christopher Womack and Robert Malina.

###


Michigan State University has been advancing knowledge and transforming lives through innovative teaching, research and outreach for 150 years. MSU is known internationally as a major public university with global reach and extraordinary impact. Its 14 degree-granting colleges attract scholars worldwide who are interested in combining education with practical problem solving.
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PostPosted: Mon Sep 18, 2006 1:45 pm    Post subject: "No time to exercise" is no excuse Reply with quote

"No time to exercise" is no excuse
September 2006
Blackwell Publishing
http://www.blackwellpublishing.....sp?ref=910
--------------------------------------------------------------------------------

A new study, published in The Journal of Physiology, shows that short bursts of very intense exercise — equivalent to only a few minutes per day — can produce the same results as traditional endurance training.


"The most striking finding from our study was the remarkably similar improvements in muscle health and performance induced by two such diverse training strategies," says Martin Gibala, an associate professor of kinesiology at McMaster University.


Gibala's team made headlines last year when they suggested that a few minutes of high-intensity exercise could be as effective as an hour of moderate activity. However, their previous work did not directly compare sprint versus endurance training.


The new study was conducted on 16 college-aged students who performed six training sessions over two weeks. Eight subjects performed between four and six 30-second bursts of "all out" cycling separated by 4 minutes of recovery during each training session. The other eight subjects performed 90-120 minutes of continuous moderate-intensity cycling each day. Total training time commitment including recovery was 2.5 hours in the sprint group, whereas the endurance group performed 10.5 hours of total exercise over two weeks. Despite the marked difference in training volume, both groups showed similar improvements in exercise performance and muscle parameters associated with fatigue resistance.


"Our study demonstrates that interval-based exercise is a very time-efficient training strategy," said Gibala. “This type of training is very demanding and requires a high level of motivation. However, short bursts of intense exercise may be an effective option for individuals who cite ‘lack of time’ as a major impediment to fitness."


Notes to Editors

1. The press release refers to:
Short-term sprint interval versus traditional endurance training: Similar initial adaptations in human skeletal muscle and exercise performance, by Martin J Gibala, Jonathan P Little, Martin van Essen, Geoffrey P Wilkin, Kirsten A Burgomaster, Adeel Safdar, Sandeep Raha, and Mark A Tarnopolsky. Published September 15 2006, The Journal of Physiology, 575.3, pp. 901-911.

2. To request a PDF version of this article, contact: Lucy.mansfield@oxon.blackwellpublishing.com

3. For further information about the press release, please contact Martin Gibala, Associate Professor, Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1, Tel: +1 905-525-9140 ext. 23591; Email: gibalam@mcmaster.ca or Jane Christmas, Office of Public Relations, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1, Tel: +1 905-525-9140 ext. 27988; Email: chrisja@mcmaster.ca


4. The Physiological Society is a learned society and a registered charity. Established in 1876, the Society promotes the advancement and communication of physiology, the science of how the body works. The Society has around 2500 members in over 50 countries, the majority at universities and engaged in research into physiology. It supports 4–5 meetings annually, publishes two journals (The Journal of Physiology and Experimental Physiology), awards grants to allow members to travel and collaborate, is represented on various councils and committees and is an active member of the Biosciences Federation. Further information is available at www.physoc.org.




5. Blackwell Publishing is the world’s leading society publisher, partnering with more than 665 academic and professional societies. Blackwell publishes over 800 journals annually and, to date, has published close to 6,000 text and reference books, across a wide range of academic, medical, and professional subjects. The company remains independent with 950 staff members in offices in the US, UK, Australia, China, Denmark, Germany, Japan, and Singapore. Blackwell’s mission as an expert publisher is to create long-term partnerships with clients to enhance learning, disseminate research, and improve the quality of professional practice. Visit our new website at www.blackwellpublishing.com for more information on Blackwell Publishing.
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PostPosted: Wed Jan 31, 2007 7:59 am    Post subject: Exercise has no effect on risk of knee osteoarthritis Reply with quote

John Wiley & Sons, Inc.
31 January 2007

Exercise has no effect on risk of knee osteoarthritis

Regular exercise is recommended for middle-aged and older people, but the effect of exercise on the development of osteoarthritis (OA) in older people is unclear, especially if they are overweight. Some studies have suggested that exercise has a protective effect, but few studies have been conducted where patients are asked about physical activity and followed to find out what develops. Meanwhile, obesity is a major risk factor for knee OA, and the question has been raised as to whether weight-bearing activity may be harmful to people who are overweight. A new study published in the February 2007 issue of Arthritis Care & Research (http://www.interscience.wiley.com/journal/arthritiscare) examined the effects of physical activity over a long period in older adults, many of whom were overweight, and found that exercise neither protects against nor increases the risk of knee OA.

Led by David T. Felson of the Boston University School of Medicine in Boston, MA, researchers conducted a study of 1,279 subjects from the Framingham Offspring cohort, which consists of the offspring of the original Framingham cohort. Persons were questioned about recent physical activity they had engaged in on a regular basis, and between one and two years later (1993-1994) had knee X-rays. They were also asked questions about knee symptoms such as pain, aching or stiffness. Between 2002 and 2005 they were called back for a follow-up exam, during which they underwent the same knee X-rays and were asked the same questions about symptoms, but not about physical activity. They were also weighed initially and at follow-up, when X-rays were read by a bone and joint radiologist and a rheumatologist.

Analysis of the results showed no relationship between recreational walking, jogging or other self-reported activity and the development of knee OA. Even though the overweight patients had an increased risk of developing OA, physical activity did not contribute to this risk. Also, despite previous studies that suggested that exercise may prevent joint space loss, the study did not find this to be the case. "This suggests that in middle-aged and older adults who do not have OA, exercise does not protect against disease development," the authors state.

The study attempted to examine all the ways in which OA might appear by looking at X-rays that indicated the development of structural disease using a well-known index (the Kellgren and Lawrence scale), by looking at joint space loss, which is thought to indicate cartilage loss, and also by examining symptoms. The authors conclude: "Physical activity can be done safely without concerns that persons will develop OA as a consequence."

In another study in the same issue, researchers led by J.N. Belo of Erasmus Medical Center in Rotterdam, Netherlands published an overview of 37 studies appearing up to December 2003 to determine predictive factors of the progression of knee OA. As was the case with the Felson study, they found three studies showing no strong evidence that regular exercise was related to progression of knee OA; Other studies found that sex, knee pain, quadriceps strength and knee injury were also not associated with progression of knee OA. On the other hand, the presence of generalized OA and the level of hyaluronic acid (a protein found in joints) were predictive of progression of the disease.

In an accompanying editorial in the current issue Marian A. Minor of the University of Missouri in Columbia, MO notes that the Felson study helps to clarify the understanding of the relationship between knee OA and physical activity by using precise definitions of OA, using valid methods to assess prior physical activity, and evaluating the true incidence of the disease by eliminating patients who showed evidence of it on X-rays taken when the study began. "Taken together, these methods result in a useful and valid study that supports recommending regular moderate physical activity without undue fear that such activity may increase the risk for knee OA," the author states. Since physical activity does not appear to increase the risk of knee OA, the author wonders what variables may possibly play a role in its development and progression. She suggests that many studies fail to collect data about knee OA, such as age at onset, occupational and medical history, and response to medication and physical therapy, that may shed some light on the disease. Noting that future research should identify variables relevant to knee OA that make a difference in individual response, the author concludes: "In addition to improving the usefulness of knee OA research, our ultimate aim must be to produce evidence that assists clinical decision-making and individualized recommendations regarding safety and effectiveness of interventions, including physical activity."


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Article: "Effect of Recreational Physical Activities on the Development of Knee Osteoarthritis in Older Adults of Different Weights: The Framingham Study," David T. Felson, Jingbo Niu, Margaret Clancy, Burton Sack, Piran Aliabadi, Yuqing Zhang, Arthritis Care & Research, February 2007; (DOI: 10.1002/art.22464).

Article: "Prognostic Factors of Progression of Osteoarthritis of the Knee: A Systematic Review of Observational Studies," J.N. Belo, M.Y. Berger, M. Reijman, B.W. Koes, S.M.A. Bierma-Zeinstra, Arthritis Care & Research, February 2007; (DOI: 10.1002/art.22475).

Editorial: "Physical Activity and Knee Osteoarthritis: Answers and Questions," Marian A. Minor, Arthritis Care & Research, February 2007; (DOI: 10.1002/art.22485).
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PostPosted: Fri Feb 16, 2007 8:06 am    Post subject: Exercise improves quality of life for people with breast can Reply with quote

BMJ-British Medical Journal
15 February 2007

Exercise improves quality of life for people with breast cancer

Group exercise sessions can help to improve the physical and psychological wellbeing of people diagnosed with breast cancer, a new BMJ study reveals today.

Breast cancer is the most commonly occurring cancer among women in the UK. Treatment for cancer, such as chemotherapy and radiotherapy, can badly affect quality of life. However, current cancer rehabilitation programmes are mainly based on psychotherapy or social support, and do not generally deal with the physical problems encountered by patients.

Researchers from Scotland set out to determine if group exercise programmes could prove beneficial to women who were having treatment for early stage breast cancer. Over 200 women took part in the study. They were split into two separate groups; the first (control group) received their usual care, whilst the second group received their usual care plus were invited to take part in a 12 week programme of exercise sessions. Participants in the second group were encouraged to attend two classes – led by trained exercise specialists - and undertake one additional exercise session at home each week.

Following the 12 week session, the researchers analysed the physical and psychological wellbeing of the participants by measuring a number of factors, such as levels of depression, quality of life, mood, shoulder mobility, walking distances and weekly levels of physical activity. These factors were measured after 12 weeks and six months later.

Participants in the second group had better outcomes on both a physical and psychological level than those who had not taken part in the exercise programme, both at the 12 week and six month assessments. Also, after six months those who had exercised had made fewer visits to their GP, and spent fewer nights in hospital, than the participants in the control group.

The researchers say that the benefits experienced by the women may have been caused by the exercise itself or by the group experience, or a combination of both. They conclude that clinicians should encourage activity during cancer treatment for patients, and policy makers should consider including opportunities for exercise in cancer rehabilitation services.
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PostPosted: Thu Mar 29, 2007 9:29 am    Post subject: Physical activity associated with lower risk of work-related Reply with quote

John Wiley & Sons, Inc.
29 March 2007

Physical activity associated with lower risk of work-related repetitive strain injury

Health benefits associated with physical activity during leisure time are widely recognized, but it is not known if leisure-time physical activity decreases the risk of work-related repetitive strain injury (RSI). A new study published in the April 2007 issue of Arthritis Care & Research (http://www.interscience.wiley.com/journal/arthritiscare) estimated the prevalence of work-related RSI and found that being physically active during leisure time is associated with a decreased risk of this type of injury.

Led by C.R. Ratzlaff, PhD(Cand), BSc(PT), FCAMT, of the University of British Columbia in Vancouver, Canada, researchers analyzed data from the 2003 Canadian Community Health Survey, a population-based national survey that provides detailed information on the type and amount of leisure-time physical activity in which respondents engaged. It included 58,622 full-time workers between the ages of 15 and 74. Respondents were included if they reported injuries due to repetitive strain that were serious enough to limit normal activities during the previous 12 months, and if these RSIs were in the upper body and associated with work-related activities. Physical activities were grouped into high upper-body load (tennis, baseball, weight training, gardening, fishing, golf, bowling, hockey, volleyball, swimming, home exercise, skiing, cycling) and low upper-body load (walking, dancing, exercise class/aerobics, ice skating, rollerblading, jogging, soccer).

The results showed that the prevalence of RSI in the overall survey population (134,072 individuals) in 2003 was approximately 10.9 percent, and the prevalence of RSIs due to work was about 4.7 percent. Upper-body injuries, the most common of which affected the wrist/hand, shoulder and elbow, accounted for over 63 percent of RSIs in full-time workers. Several factors were associated with upper-body work-related RSIs, including, physical work demands, work-related stress, obesity and daily smoking,. Women and those aged 30-49 were also at higher risk. While higher levels of physical activity may place increased load on the musculoskeletal system that could potentially contribute to RSI, the study found no such link. However, it did find that being physically active was protective against RSI, as was being over 50 years old.

"This finding provides evidence for a hypothesis that an active lifestyle outside of work may protect against work-related RSI, adding another potential health benefit to leisure-time physical-activity participation," the authors state. They note that this type of activity may play a role in facilitating mechanical and metabolic processes in the musculoskeletal system that counter the repetitive or sedentary effects of many jobs. It may also offset muscle weakness in the upper body, and provide better balance of movement and muscle activity. It may be that those with RSIs are less likely to be active outside of work because of their injuries, however such injuries would not necessarily limit activities such as walking.

"Work-related RSI is a common problem that has significant costs in terms of lost wages and productivity, medical care, and quality of life," the authors note, adding that it is a growing problem in Canada that may be associated with an increase in sedentary occupations and lifestyles. "It is important to identify lifestyle factors that may protect against RSI in order to inform employers, compensation boards, and the working population," they conclude. "Identification of safe physical activities may reduce RSI and provide multiple other health benefits."


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Article: "Work-Related Repetitive Strain Injury and Leisure-Time Physical Activity," C.R. Ratzlaff, J.H. Gillies, M.W. Koehoorn, Arthritis Care & Research, April 2007; (DOI: 10.1002/art.22610).
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PostPosted: Thu Apr 12, 2007 10:01 am    Post subject: U of M study shows physical activity reduces risk of hyperte Reply with quote

University of Minnesota
12 April 2007

U of M study shows physical activity reduces risk of hypertension in young adults

Young adults who spend more time participating in physical activity have a reduced risk of developing high blood pressure within the next 15 years, according to researchers at the University of Minnesota.

Research published in the April 2007 issue of the American Journal of Public Health found that young adults who exercised an average of five times a week and expended 300 calories per exercise session experienced a 17 percent reduction in the risk of developing hypertension.

In addition, study participants who maintained or increased their total time participating in physical activity from the start of the study to the finish decreased their risk of high blood pressure by 11 percent for every 1,500 calories they burned weekly.

"This study is the first of its kind to examine the link between physical activity and hypertension in young adults," said David Jacobs, Ph.D., study co-author and professor of epidemiology and community health at the University of Minnesota School of Public Health. "The study further confirms evidence that physical activity is related to hypertension."

Jacobs and colleague Emily Parker, lead author of the study and doctoral student at the University of Minnesota School of Public Health, analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which tracked physical activity and measured blood pressure levels in nearly 4,000 men and women over a 15-year period.

Overall, 634 adults developed cases of hypertension over the 15 years of follow-up. After adjusting for race, age, sex, education, and family history, data showed that those participants who were more physically active experienced a reduced risk for hypertension compared with those who were less physically active. "This study shows that physical activity should be considered in the prevention of hypertension in young adults," said Jacobs. "This link gives people another reason to increase their levels of exercise and remain physically active."

###
This study was supported by the National Health, Lung, and Blood Institute.
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PostPosted: Fri May 04, 2007 9:22 am    Post subject: Vigorous Exercise Keeps People Thin with Age Reply with quote

Vigorous Exercise Keeps People Thin with Age
Berkeley Lab
3 May 2007

BERKELEY, CA -- The old adage “use it or lose it” is truer than ever. People who maintain a vigorously active lifestyle as they age gain less weight than people who exercise at more moderate levels, according to a first-of-its-kind study that tracked a large group of runners who kept the same exercise regimen as they grew older.

The study also found that maintaining exercise with age is particularly effective in preventing extreme weight gain, which is associated with high blood pressure, high cholesterol, diabetes, and other diseases.

The study, conducted by Paul Williams of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), followed 6,119 men and 2,221 women who maintained their weekly running mileage (to within three miles per week) over a seven-year period. On average, the men and women who ran over 30 miles per week gained half the weight of those who ran less than 15 miles per week.

“To my knowledge, this is the only study of its type,” says Williams, a staff scientist in Berkeley Lab’s Life Sciences Division. “Other studies have tracked exercise over time, but the majority of people will have changed their exercise habits considerably.”

The research is the latest report from the National Runners' Health Study, a 20-year research initiative started by Williams that includes more than 120,000 runners. It appears in the May 3 issue of the journal Medicine and Science in Sports and Exercise.

Specifically, between the time subjects entered the study and when they were re-contacted seven years later, 25-to-34-year-old men gained 1.4 pounds annually if they ran less than 15 miles per week. In addition, male runners gained 0.8 pounds annually if they ran between 15 and 30 miles per week, and 0.6 pounds annually if they ran more than 30 miles per week.

This trend is mirrored in women. Women between the ages of 18 and 25 gained about two pounds annually if they ran less than 15 miles per week, 1.4 pounds annually if they ran 15 to 30 miles per week, and slightly more than three-quarters of a pound annually if they ran more than 30 miles per week. Other benefits to running more miles each week included fewer inches gained around the waist in both men and women, and fewer added inches to the hips in women.

“As these runners aged, the benefits of exercise were not in the changes they saw in their bodies, but how they didn’t change like the people around them,” says Williams.

Although growing older and gaining weight is something of a package deal, it isn’t the same in everyone. The lucky few remain lean as they age, most people pack on several pounds, and some people become obese. The latter group is particularly at risk for high blood pressure, high cholesterol, and diabetes. Fortunately, Williams’ results show that maintaining exercise can combat such extreme weight gain.

“Getting people to commit to a vigorously active lifestyle while young and lean will go a long way to reducing the obesity epidemic in this country,” says Williams.

Another paper published in the November 2006 issue of the journal Obesity by Williams and Paul Thompson of Hartford (CT) Hospital found that runners who increased their running mileage gained less weight than those who remained sedentary, and runners that quit running became fatter.

“The time to think about exercise is before you think you need it,” says Williams. “The medical journals are full of reports on how difficult it is to regain the slenderness of youth. The trick is not to get fat.”

Williams’ research was funded by the National Heart, Lung and Blood Institute. The May 3 paper in the journal Medicine and Science in Sports and Exercise is entitled Maintaining Vigorous Activity Attenuates 7-yr Weight Gain in 8,340 Runners.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our Website at http://www.lbl.gov.
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PostPosted: Mon May 28, 2007 8:01 am    Post subject: Inactive kids storing up illness for the future Reply with quote

University of Leicester
28 May 2007

Inactive kids storing up illness for the future

University of Leicester academics publish results of one of the largest studies of physical activity among inner city school children
A new University of Leicester study funded by the British Heart Foundation reveals that the level of physical inactivity among children today has reached epidemic levels. Researchers from Leicester -Professor Kamlesh Khunti, Professor Melanie Davies and Dr Margaret Stone- have just published one of the largest studies of physical activity levels of inner city school children.

They surveyed over 3500 pupils from five inner city secondary schools in Leicester. They identified low levels of physical activity in both South Asian and white children. For example only half the children walked to school although south Asian children were less likely to walk to school compared to white children. Furthermore, half the pupils spent 4 hours or more a day watching television or videos or playing computer games. Family history of diabetes or heart disease in parents is a risk factor for development of diabetes or heart disease in their children. However, the researchers found that children of parents with a family history of diabetes or heart disease were just as likely to have sedentary behaviours as those without a family history.

Professor Khunti said: “People of South Asian origin comprise significant-sized minority ethnic populations in many countries worldwide. A consistent finding in South Asian migrant populations, wherever they are located, is a higher incidence and prevalence of premature coronary heart disease compared with the local population.

“Metabolic abnormalities precede the development of diabetes by some years and risk factors for cardiovascular disease in children often persist into adulthood. There is also evidence of increased risk of cardiovascular risk factors in children of South Asian origin compared to white children. The need to implement prevention strategies for childhood obesity is therefore a major target for the government and health care professionals.

“Inactive behaviour, such as watching television, may predict subsequent adult overweight and obesity in children and adolescent. However, there is a lack of data on physical activity levels of South Asian children despite them having a higher cardiovascular risk profile.

‘This study shows that overall the physical activity levels in inner city school children are very low and parents, schools and community health providers need to address the results of these findings to reduce their future risks of developing diabetes and heart disease in children ”.
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PostPosted: Wed May 30, 2007 11:11 am    Post subject: Research shows aerobic exercise helps maintain muscle in eld Reply with quote

University of Texas Medical Branch at Galveston
30 May 2007

Research shows aerobic exercise helps maintain muscle in elderly
Crucial muscle-building insulin response restored with a 45-minute walk
GALVESTON, Texas — Why do older people tend to lose muscle mass and grow frail? One important factor identified by medical science is the reduced ability of the elderly to respond to the muscle-building stimulus of the hormone insulin.

Insulin is best known for its link to diabetes — a condition in which either a complete lack of insulin or systemic resistance to the hormone's activity (as in type 2 diabetes) causes blood sugar levels to soar out of control. Recent studies have shown, however, that insulin also provides crucial assistance in building muscle, and that its ability to do so drops off dramatically in the elderly.

Now, a small but provocative study by medical researchers in Texas and California suggests that a simple, cost-free therapy appears to largely overcome that drop-off in insulin response: moderate aerobic exercise such as walking.

Experiments at the University of Texas Medical Branch at Galveston (UTMB) and the University of Southern California, Los Angeles conducted on 13 healthy volunteers in their late 60s showed that 45 minutes of walking 20 hours before exposure to insulin restored the muscle-growth-stimulating effects of the hormone to levels comparable to those seen in normal young adults.

Prior research had suggested that a large part of the problem older people experience lies in the tiny blood vessels that feed the muscles protein-building amino acids, glucose and insulin (which itself also works within muscle cells as a powerful protein growth factor). In young adults, these normally closed vessels open wide in response to the insulin increase generated by a meal, providing clear passage for muscle-making materials. In elderly people, however, this process, known as "vasodilation," is much less pronounced.

"We thought, let's see what happens if we use aerobic exercise, one of the interventions that has been shown in the past to improve vasodilation, to find out whether we can get insulin to stimulate muscle synthesis in older people," said UTMB professor Elena Volpi, senior author of a paper on the experiments appearing in the June issue of the journal Diabetes. "It turned out that a fast walk restored the insulin response quite well."

To test their hypothesis, the researchers first required six of their 13 subjects to walk for 45 minutes on a treadmill quickly enough to keep their hearts beating at 70 percent of their maximum rate —the same aerobic intensity level recommended to maintain cardiovascular fitness. The other seven subjects simply rested.

On the following morning, the researchers sampled the blood going into and coming out of thigh muscle in each of the volunteers, while supplying via the femoral artery a concentration of insulin similar to that released after a typical meal. They also took three small muscle tissue samples from each subject.

Tracer techniques enabled the scientists to track amino acids (the building blocks of muscle proteins) and determine muscle-protein synthesis and breakdown rates from the blood and muscle samples, while measuring blood flow at the same time. These revealed that the volunteers who exercised had both higher blood flow and net muscle protein growth. In addition, the researchers screened the muscle biopsy samples for signals associated with insulin's ability to stimulate the assembly of muscle protein from amino acids. This test also showed that exercise boosted insulin's role as a muscle protein growth factor.

"We already know that moderate aerobic exercise reduces cardiovascular disease, improves glucose uptake, and improves endurance," Volpi said. "Now it looks like it may also slow the rate of muscle loss in aging. We need to test this hypothesis further with larger trials, but still, it's one more reason why elderly people ought to be regularly walking, swimming or cycling."


###
Other authors of the Diabetes paper are UTMB postdoctoral fellows Satoshi Fujita and Jerson Cadenas, associate professor Blake B. Rasmussen, physical therapy graduate students Micah J. Drummond and Erin L. Glynn, and USC-Los Angeles professor Fred R. Sattler.

This research was supported by two grants from the National Institute on Aging, including UTMB's Claude D. Pepper Older Americans Independence Center; the Robert E. and May R. Wright Foundation; the National Institute for Arthritis and Musculoskeletal and Skin Diseases; and the NIH-funded General Clinical Research Centers at UTMB and USC.

-UTMB-
The University of Texas Medical Branch at Galveston
Public Affairs Office www.utmb.edu
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PostPosted: Tue Jun 12, 2007 9:37 am    Post subject: Light activity can help avoid chronic disease Reply with quote

Research Australia
11 June 2007

Light activity can help avoid chronic disease

This is according to new research undertaken by The University of Queensland and Melbourne's International Diabetes Institute.

The research, published this month in the international journal, Diabetes Care, has not only confirmed that a sedentary lifestyle is associated with high blood glucose levels, but for the first time has shown that light intensity physical activity, like washing dishes, ironing and other routine domestic or occupational tasks, was associated with lower blood glucose levels.

High glucose levels are a precursor to diabetes and cardiovascular disease.

School of Population Health researcher Mrs Genevieve Healy said this was good news for the general population, but particularly for those who are overweight and at higher risk of developing chronic disease.

Associate Professor David Dunstan, senior research fellow from the International Diabetes Institute and co-author on the paper, said the message that 30 minutes of moderate to vigorous exercise a day was important for good health, still stood.

"This research suggests that there are also real benefits from reducing sedentary time and increasing the time spent on normal daily activities,” Dr Dunstan said.

Mrs Healy suggested that ”folding clothes or ironing as you watch TV, standing while on the phone or walking to see an office colleague rather than emailing them, are simple and easy ways to do this.”

The study recruited participants from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) and involved measuring the glucose levels and daily activities of 173 men and women over a week.

Accelerometers were used to measure the intensity, frequency and duration of the activities.

The new evidence provided by this research points to a preventive strategy that may be more achievable for people who are at risk of type 2 diabetes and cardiovascular disease, but are not exercise conscious.
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PostPosted: Sat Jun 16, 2007 6:03 am    Post subject: Runners: Let Thirst Be Your Guide Reply with quote

Runners: Let Thirst Be Your Guide
16 June 2007
Georgetown University

Experts advise endurance exercisers to rely on thirst as a way to limit excess use of water



Washington, DC--Many people are drinking too much water, including sports drinks, when exercising, a practice that could put some individuals engaging in prolonged types of endurance exercise at risk of potentially lethal water intoxication, say international experts who study disorders of water metabolism. Such exercise includes marathons, triathlons, and long distance cycling.



This serious condition, known as exercise-induced hyponatremia (EAH), could be prevented if only people would respect their personal thirst “meter,” or would undertake a “sweat test” to determine how much water they actually need to drink in order to replace just the body fluids lost during exercising, the researchers say.



A group of experts in this condition has issued a number of papers and recommendations, including an international consensus statement on this disorder published in the Clinical Journal of Sports Medicine in 2005. Joseph Verbalis, M.D., Professor and Interim Chair of the Department of Medicine at Georgetown University Medical Center and a member of this group, recently updated the scientific community on the causes of this disorder in the May issue of Sports Medicine.



Verbalis says the goal of the group is to understand the biological basis of EAH, and in that way, assure that no athlete ever succumbs to it again. A number of marathon runners have died from EAH, including one at this year’s London Marathon in April. One recent study found that 13 percent of Boston marathon runners suffered from EAH, though most cases are mild enough so that they are not noticed by the athletes themselves.



“The tragic aspect of the deaths that have occurred from EAH is that these are healthy young people who otherwise would have lived normal, long lives,” says Verbalis, who is also Chief of the Division of Endocrinology and Metabolism at Georgetown.



“The data clearly indicate that EAH is caused by excess drinking during endurance exercise activities, and that it can be prevented by limiting fluid intake while exercising, he says. But despite this knowledge, Verbalis points out that “unfortunately, we are not seeing this condition go away."



“The public’s impression of the amount of water that is necessary to drink for good health is not based on real factual data,” he says. “Many in our society have promoted the idea that you need to continually drink a large amount of fluid, such as 8 ounces of water eight times a day. But most people don’t really need that much.”



Verbalis points out that EAH predominantly afflicts exercisers engaging in endurance activities of 4 hours in duration or longer. But “the average person who goes out for an hour or two of strenuous exercise is not going to be at risk for this,” he adds.



Verbalis also says that sports drinks, which contain some sodium and potassium and carbohydrates, are basically water with a few additives. “There’s a misconception among the sports community that consuming sports drinks rather than water will protect you from becoming hyponatremic. That’s simply not true,” he says. “Drinking too much of anything puts some people at risk for potentially dangerous levels of hyponatremia.”



The disorder occurs when endurance exercisers drink more fluid than their kidneys can excrete. The hormone that determines how much fluid a kidney can excrete is arginine vasopressin (AVP), which is released from the pituitary gland when a person is becoming dehydrated in order to force the kidneys to conserve water. At rest, a person’s AVP level is low and can be suppressed to zero when sufficient fluids are ingested so that the kidney can excrete, rather than retain, excess water. But AVP levels can rise in people who exercise strenuously over a number of hours, even if they are not dehydrated.



“A kidney can normally excrete up to a liter an hour with an AVP level of zero, but when you’re exercising, the AVP is telling your kidney to excrete a volume of fluid that is markedly less than the maximum the kidney can excrete at rest,” Verbalis says. Too much water intake in an endurance exerciser whose AVP levels are on the rise means that some of the ingested water will be retained, and that excess water can dangerously dilute the level of sodium in the blood that is needed for organs to function, he adds.



Investigators have been researching the triggers that stimulate AVP secretion during exercise, and have found several. One is a loss of fluid from the body and blood as a result of sweating during prolonged exercise. Another is nausea, a common reaction to extreme sports, which makes the body think vomiting will ensue, so water needs to be conserved, Verbalis says. Finally, a research team that included Verbalis recently reported in the American Journal of Medicine that release from muscles of a cytokine known as interleukin-6 (Il-6) is also capable of stimulating AVP secretion.



Verbalis noted in his Sports Medicine paper that since 1985, “well over 100 individual cases” of EAH have been reported from physical exercise activities as diverse as forced military marches, prolonged hiking and marathon, ultramarathon and triathlon races, and there have been at least 8 documented fatalities. Some people have been known to gain up to 6-7 pounds during a marathon due to retention of water that the kidneys cannot excrete, he says. “No one should be gaining any weight during these events,” according to Verbalis, “and if they do, it can only be due to fluid retention.”



The hyponatremia consensus panel has recommended that everyone, including endurance exercisers, should “drink to thirst” ? that is, drink only when you feel you need to. Verbalis acknowledges that this advice is controversial, because some trainers and sports physiologists contend that “by the time you’re actually thirsty, you have lost enough fluid to already be dehydrated, so they say you need to drink in anticipation of becoming dehydrated.



“We dispute that notion, and contend that thirst is a good indicator of your body’s need for fluids, and that there is a window of time over which you can rehydrate safely,” he says. While a person “needs to lose about 1-2 percent of body water before thirst will reliably remind you to drink, losing that little is not sufficient to cause any significant health problems,” Verbalis says. “Many of us are often dehydrated to such small degrees, and it does not significantly affect us.”



But he adds that endurance exercisers who don’t want to rely on their body’s thirst meter have another excellent option, and that is undertaking a sweat test. This involves recording a person’s weight digitally, then running on a treadmill for an hour and recording their ending weight after toweling off the body sweat. “Most people don’t know how much they really sweat while exercising, but this simple test can tell you approximately how much fluid losses you are generating from sweat,” he says. “There is no need to drink significantly more than that, because sweat represents the major source of fluid loss during exercise.”



A healthy person needs to be dehydrated in the range of 4-6 percent loss of body water before there’s a significant health risk problem from dehydration, Verbalis says. “So, really, if people just do things in moderation, especially including re-hydrating by drinking, they’re not going to be at risk of either dehydration from excessive sweat losses or EAH from excessive fluid ingestion.”



About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through our partnership with MedStar Health). Our mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis -- or "care of the whole person." The Medical Center includes the School of Medicine and the School of Nursing and Health Studies, both nationally ranked, the world-renowned Lombardi Comprehensive Cancer Center and the Biomedical Graduate Research Organization (BGRO).
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PostPosted: Tue Jun 19, 2007 11:12 am    Post subject: Burning fat and carbohydrate during exercise Reply with quote

Blackwell Publishing Ltd.
18 June 2007

Burning fat and carbohydrate during exercise

In a paper published in The Journal of Physiology, Helge, Stallknecht, Richter, Galbo, and Keins from Copenhagen shed light on fat oxidation during exercise and physical activity. Their observations suggest that fat oxidation during exercise reflects a fine interplay between the cardiovascular, neurological, endocrine and muscle metabolic systems.

During exercise and physical activity, the primary fuels used by muscles are carbohydrate and fat. When mild exercise is performed there is a tendency to burn relatively more fat and less glucose, but as exercise becomes more intense, a higher fraction of the energy demands of the muscle are supplied by glucose, until at the highest intensities almost only carbohydrates are used. Is this shift in fuel source a property of the muscle itself, or does it represent the interplay between what is happening in the muscle and the exercise-related responses in the rest of the body"

The study, performed at the Copenhagen Muscle Research Centre at the University of Copenhagen, examined muscle fuel utilisation in response to graded exercise performed with only one leg. Nine healthy males performed one-leg exercise at 25, 45, and 85% of maximal workload. Their results showed that, when only a small mass of muscle is contracting, and blood flow and oxygen supply are not limited by central circulatory capacity, the shift in fuel source from fat to glucose as exercise intensity increases does not occur.

Helge et al.’s findings show that the adaptations in the rest of the body are the key to this fuel source shift during whole body exercise. They also help scientists understand why athletes "hit the wall" during events like the marathon, and they have implications for the adaptations made in middle-aged adults who are using exercise to prevent or treat conditions like diabetes and obesity. If the mechanisms can be fully understood, it may be possible to develop agents that allow fat oxidation to be maintained even during intense exercise with a large muscle mass.
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PostPosted: Tue Jun 26, 2007 10:58 am    Post subject: Increasing physical activity with a little boost Reply with quote

Temple University
26 June 2007

Increasing physical activity with a little boost

Simple personalized program delivered by mail more effective than one-on-one phone counseling

As Americans struggle to become more physically active, simple programs that provide feedback and motivation can play a crucial role in getting people off to a good start, according to a study of the July issue of Health Psychology.

Researchers found feedback delivered via mail was equally as effective at increasing physical activity in the short-term and potentially more effective long-term than feedback delivered via phone counseling.

The study enrolled 239 healthy, underactive adults into two individualized programs either with telephone-based or print-based feedback for one year. A control group received generic health information with no physical-activity specific information. They then could chose either the print or phone program after one year. Study participants submitted data about their physical activity in personal logs and surveys.

The print and telephone based programs incorporated social cognitive theory and the transtheoretical model both of which emphasize the importance of increasing motivational readiness for physical activity, balancing the pros vs. cons of activity, and developing strategies for becoming and remaining physically active, said Melissa Napolitano, Ph.D, an author of the study at Temple University and expert in physical activity initiation, adoption and maintenance.

“Both programs offer a cost-effective way to promote healthy behaviors, such as exercise,” Napolitano said.

Feedback, whether delivered via phone by a health educator or via a printed letter, pointed out areas for improvement and recognized successful efforts by the participants.

Researchers designed the program to encourage participants to reach the national guidelines for physical activity at 150 minutes per week. They completed a physical activity log and brief survey each month, and two in person visits. Compensation was provided for each completed activity.

Currently, people can find phone counseling programs through outlets such as their health insurance providers. Other programs are available online and in print-based formats. For example, the American Heart Association has a program designed for women, Choose to Move (www.choosetomove.org, print materials available by calling 1-888-MY-HEART), which promotes healthy eating and physical activity.

Inactive adults nearly double their risk for cardiovascular disease. Only 25 percent of Americans meet the recommended levels of physical activity, defined by engaging in moderate intensity activity four days or more each week for 30 minutes or vigorous activity for 30 minutes for 3 days or more each week, according to the Centers for Disease Control and Prevention.

However, CDC data suggests more Americans are trying to increase their physical activity levels. People engaging in no physical activity decreased from about 31 percent in 1989 to 25 percent in 2005 in an analysis of 36 states.

“With print, computer and telephone-based programs it is possible for larger numbers of inactive and underactive adults to receive critical help, support, and advice for becoming more physically active and ultimately preventing disease and disability,” Napolitano said.

At 6 months, the print group and telephone group reported 129 and 123 minutes of physical activity, respectively. By the end of the study at 12 months, those in the print program reported 160 minutes of physical activity a week compared to 100 minutes in the phone group and 90 minutes in the control group.

While this finding was unanticipated, there are some explanations why the researchers think this might have happened. First, the print group received hard-copies of all the materials which they could use as a resource throughout the 12 months, whereas the phone group only received verbal feedback and information.

Secondly, it is possible that the print group had to develop more internal or intrinsic motivation as they didn’t have the specific social support and contact with a personal health educator. Whereas the phone participants may have been relying more on extrinsic motivation, or the support and encouragement of the counselor. The counseling was helpful in the short-term, but may not have been as effective as the contact tapered off through the maintenance phase.

Future studies should examine whether the combination of the print and phone programs could produce even better results, and different delivery channels, such as email, text messaging and the Internet, Napolitano said.


###
This research was supported in part through a grant from the National Heart, Lung, and Blood Institute by (#HL64342) to Bess Marcus, PhD. Napolitano was a Co-Investigator on the award. Napolitano conducted the research when she was at The Miriam Hospital and Brown Medical School.
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PostPosted: Fri Jun 29, 2007 12:04 pm    Post subject: Exercise Grows New Brain Cells Reply with quote

Exercise Grows New Brain Cells
By Jeanna Bryner, LiveScience Staff Writer

posted: 28 June 2007 12:25 pm ET

Exercise stimulates the growth of new brain cells, a new study on rats finds. The new cells could be the key to why working out relieves depression.

Previous research showed physical exercise can have antidepressant effects, but until now scientists didn’t fully understand how it worked.

Astrid Bjornebekk of the Karolinska Institute in Sweden and her colleagues studied rats that had been genetically tweaked to show depressive behaviors, plus a second group of control rats. For 30 days, some of the rats had free access to running wheels and others did not.

Then, to figure out if running turned the down-and-out rats into happy campers, the scientists used a standard “swim test.” They measured the amount of time the rats spent immobile in the water and the time they spent swimming around in active mode. When depressed, rats spend most of the time not moving.

For the full article:

http://www.livescience.com/hea.....brain.html
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PostPosted: Sat Jul 07, 2007 7:17 am    Post subject: Research suggests fitness may reduce inflammation Reply with quote

Research suggests fitness may reduce inflammation

Melissa Mitchell, News Editor

Released 7/5/07

Jeffrey A. Woods, professor of kinesiology and community health, and Victoria J. Vieira, a predoctoral fellow in kinesiology and community health and in nutritional sciences, are co-authors of a new study. Their research may help explain some of the underlying biological mechanisms that take place as a result of regular exercise.


CHAMPAIGN, Ill. — Although a number of studies have suggested that regular exercise reduces inflammation – a condition that is predictive of cardiovascular and other diseases, such as diabetes – it’s still not clear whether there is a definitive link. And if such a link exists, the nature of the relationship is by no means fully understood.

A recent study by kinesiology and community health researchers at the University of Illinois provides new evidence that may help explain some of the underlying biological mechanisms that take place as the result of regular exercise. According to the researchers, that knowledge could potentially lead to a better understanding of the relationship between exercise and inflammation.

The objective of their research was to examine the independent effect of parasympathetic tone – in this case, determined by assessing heart-rate recovery after exercise – on circulating levels of C-reactive protein (CRP). Parasympathetic tone and its inverse function – sympathetic tone – are components of the autonomic nervous system. CRP, which is secreted by the liver, circulates in the bloodstream and is a biomarker for inflammation in the body.

“The sympathetic nervous system speeds things up, and the parasympathetic slows things down,” said Victoria J. Vieira, a predoctoral fellow in kinesiology and community health and in nutritional sciences, and the primary author and designer of the study, published in a recent issue of the Journal of the American Geriatrics Society. “So when you’re exercising, your sympathetic nervous system will be on, increasing your heart rate, your respiration, etc. Once you stop, your body always tries to get back to homeostasis. So the parasympathetic nervous system kicks in to get everything back down to baseline levels.”

Co-author and kinesiology and community health professor Jeffrey A. Woods said cardiologists are already routinely gauging CRP levels in much the same way they look at lipids panels to assess cholesterol levels.

“Certainly, that’s being done in the cardiovascular disease realm, but I think (it may be effectively used as a monitor) for other diseases, such as Alzheimer’s, diabetes and metabolic syndrome,” he said.

Woods said the main question motivating the current research was, “What factors are related to CRP in the elderly?”

“We’ve known that as people age, their CRP levels go up,” Vieira said. “That’s one of the reasons why older individuals are more prone to develop inflammation-related diseases such as diabetes and heart disease. So we just wanted to look at what’s predicting those levels of CRP in an average older population that is relatively healthy.”

Perhaps the most notable result of the study, according to the researchers, relates to heart-rate recovery following exercise.

“The quicker the individuals were able to get back to their resting heart rate after a strenuous exercise test was inversely related to their CRP,” Vieira said. “In other words, individuals who had better parasympathetic tone had lower levels of inflammation.

“And the reason we’re excited about this is that exercise is a great way to improve parasympathetic tone. When you exercise – that is the sympathetic/parasympathetic communication – your sympathetic goes up, and when you stop exercising, your parasympathetic kicks in to bring you back to normal. An untrained person will take a while to get their heart rate back down to resting. A trained person’s heart rate will come back down very quickly.”

The cross-sectional study focused on baseline test results from 132 sedentary, independently living individuals aged 60 to 83 (47 males; 85 females) who had been recruited to participate in the Immune Function Intervention Trial (ImFIT), a randomized longitudinal trial designed by Woods and funded by the National Institute on Aging to examine the relationship between exercise and immune function.

Participants included only individuals who did not take medications that included corticosteroids, which could interfere with immune measurements. Smokers and/or those with severe arthritis, a history of cancer or inflammatory disease, chronic obstructive pulmonary disorder, uncontrolled diabetes mellitus, congestive heart failure, recent illness or vaccination, or a positive stress test were excluded.

The physical fitness of subjects was assessed through a battery of tests that measured such variables as fatigue, blood pressure, oxygen intake and carbon dioxide elimination and heart-rate recovery in conjunction with exercise on a walking treadmill. Tests also were administered to determine the subjects’ levels of physical activity, physical fitness, emotional stress and body composition (bone density and body fat). Blood samples also were drawn to measure CRP levels.

“The major criterion we were looking at was their fitness level,” Vieira said. “A strength of our study is that we have very good data on their fitness levels.”

And while other studies have explored the relationship between exercise and inflammation, another unique aspect of the U. of I. research, Vieira said, is that “no other studies have adjusted for fitness and body fat percentages simultaneously to really get at that question, ‘Is exercise independently reducing CRP levels, or is it modulated through a decrease in adiposity (body fat)?’ ”

Because the study was cross-sectional – meaning the researchers essentially took a snapshot of the participants’ reactions and measurements at a single, fixed point only – Vieira said it was important to note that “we can’t say anything about cause and effect relationships.”

However, Woods said, “it gives you some idea of what factors are related, and then you test those in a more rigorous manner.”

Vieira said the research “certainly suggests that fitness may be associated with a decrease in inflammation even independent of body fat and several things, and the mechanism may involve a parasympathetic anti-inflammatory reflex.”

“We know inflammation is bad. We know it increases as we age, with stress and other things,” she said. “So if we can decrease that to protect ourselves somehow by just adopting a physically active lifestyle, that’s definitely an advantage.”

And while the study confirms the conclusions of previous research by others indicating that high body fat is related to high inflammation and high fitness to low inflammation, “the unique part of this paper is that controlling for those, we also show that high parasympathetic tone is related to low inflammation,” Woods said.

“And it’s even independent of their fitness level,” Vieira interjected.

“Fitness, fatness and parasympathetic tone appear to be important,” Woods said, summing up the findings. “And at least according to our results, parasympathetic tone might even be more important than those other factors.”

Co-authors with Vieira and Woods of the study are U. of I. kinesiology and community health professors Ellen Evans and Edward McAuley, and graduate student Rudy J. Valentine.
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PostPosted: Thu Jul 12, 2007 2:17 pm    Post subject: When it comes to walking, it's all good, says Mayo Clinic re Reply with quote

Mayo Clinic
11 July 2007

When it comes to walking, it's all good, says Mayo Clinic researcher

ROCHESTER, Minn. -- These days, it’s easy for people to get confused about exercise -- how many minutes a day should they spend working out, for how long and at what exertion level" Conflicting facts and opinions abound, but one Mayo Clinic physician says the bottom line is this: walking is good, whether the outcome measurement is blood pressure, diabetes, cardiovascular disease, joint problems or mental health.

“Getting out there and taking a walk is what it’s all about,” says James Levine, M.D., Ph.D., and a Mayo Clinic expert on obesity. “You don’t have to join a gym, you don’t have to check your pulse. You just have to switch off the TV, get off the sofa and go for a walk.”

The health benefit associated with walking is the subject of Dr. Levine’s editorial in the July issue of Mayo Clinic Proceedings. Dr. Levine’s piece is entitled, “Exercise: A Walk in the Park"” and accompanies a Proceedings article that showcases the merits of walking as beneficial exercise.

The study, undertaken by physicians from the Shinshu University Graduate School of Medicine in Matsumoto, Japan, determined that high-intensity interval walking may protect against high blood pressure and decreased muscle strength among older people.

Over five months, the Japanese researchers studied 246 adults who engaged in either no walking or moderate to high-intensity walking. The group who engaged in high-intensity walking experienced the most significant improvement in their health, the researchers found.

In his editorial, Dr. Levine says the study lends credence to the notion that walking is a legitimate, worthy mode of exercise for all people. Dr. Levine says it’s a welcome message for his patients, who fight obesity and appreciate that a walk is one way to improve their health.

Unlike a health club membership or personal trainer, walking “is there for everyone,” Dr. Levine says. “Walking doesn’t cost you anything, you can do it barefoot and you can do it now, this minute.”

“Sitting is bad for cholesterol, it’s bad for your back and muscles,” Dr. Levine says. “It’s such a terrible thing for our bodies to do and the less of it you do, the better. But activity is not easy. If it were easy, everyone would do it.”


###
Authors for the study in Mayo Clinic Proceedings on high-intensity walking were Ken-Ichi Nemoto; Hirokazu Gen-No, Ph.D.; Shizue Masuki, Ph.D.; Kazunobu Okazaki, Ph.D.; and Hiroshi Nose, M.D., Ph.D., all from the Shinshu University Graduate School of Medicine.
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PostPosted: Fri Sep 28, 2007 7:59 pm    Post subject: The impact of physical activity on weight-bearing knee joint Reply with quote

John Wiley & Sons, Inc.
28 September 2007

The impact of physical activity on weight-bearing knee joint

Exercise for cardiovascular health keeps knee cartilage healthy, too, suggests long-term, community-based study
The world’s most common joint disease, osteoarthritis (OA) is a major cause of disability among adults over the age of 50. Whether physical activity is beneficial or detrimental to weight-bearing joints, knees in particular, has been open to debate. Some studies implicate physical activity in provoking knee OA, while others suggest that physical activity may actually protect the knee joint from the disease. Confounding the matter is the fact that knee injury is a known risk factor for knee OA. Then, there’s the unclear role of osteophytes in knee OA progression, compounded by the limitations of radiographs for monitoring small yet significant changes in joint structure.

For a clearer picture of the impact of physical activity on the knee joint, a team of researchers in Australia turned to magnetic resonance imaging (MRI). This highly accurate high-tech tool makes it possible to directly visualize joint structures, detect early and pre-disease states of OA, and assess the influence of potential risk factors. Taking advantage of this novel methodology, the researchers studied the effect of physical activity, in various degrees of intensity, frequency, and duration, on knee structures in a total of 257 healthy adults between the ages of 50 and 79, with no history of knee injury or OA. Their findings, presented in the October 2007 issue of Arthritis Care & Research ( http://www.interscience.wiley......hritiscare ), suggest that exercise that is good for the heart is also good for the knee.

Recruited from an established community-based research population, the Melbourne Collaborative Cohort Study, subjects all underwent MRI exams on the tibia bone and tibiofemoral joint of their dominant knee—the one on the leg they first step forward when walking. MRI was used to assess cartilage defects and bone marrow lesions, as well as measure cartilage volume, an indicator of cartilage health and strength. Loss of knee cartilage is linked to worsening knee symptoms in OA sufferers. Subjects also answered specific questions regarding their exercise and walking habits, as well as routine activity at home and at work, to determine their level of physical activity in both the 6 months and 7 days prior to the study. To create a baseline for each subject, past information on weight, height, body mass index, and physical activity, from questionnaires completed between 1990 and 1994, was obtained. Then, the team performed a series of analyses and comparisons.

Among the notable findings, both baseline and current vigorous physical activity— exercise that gets the heart pumping and the body sweating—were associated with an increase in tibial cartilage volume, free from cartilage defects. What’s more, tibial cartilage volume increased with frequency and duration of vigorous activity. Recent weight-bearing exercise was also linked to increased tibial cartilage volume and reduced cartilage defects. Finally, moderate physical activity, including regular walking, was associated with a lower incidence of bone marrow lesions.

“This is the first study to demonstrate a potentially beneficial effect of walking on the reduction in the risk of bone marrow lesions in the knee,” notes the study’s leading author, Dr. Flavia M. Cicuttini. “Bone marrow lesions have been associated with pain and radiograph-defined progression of osteoarthritis, type II collagen degradation, and loss of cartilage volume.”

Demonstrating a protective effect of past and current vigorous physical activity on knee cartilage in healthy adults, this study strongly supports the benefits of exercise for older individuals at risk for OA. Though both the intensity and duration of physical activity had a significant positive impact on cartilage, the ideal amount of physical activity for joint health remains unclear. “Our data suggest that at least 20 minutes once per week of activity sufficient to result in sweating or some shortness of breath might be adequate. This is similar to, if not somewhat less than, the recommendations for cardiovascular health,” Dr. Cicuttini observes.


###
Article: “Effect of Physical Activity on Articular Knee Joint Structures in Community-Based Adults,” Tina L. Racunica, Andrew J. Teichtahl, Yuanyuan Wang, Anita E. Wluka, Dallas R. English, Graham G. Giles, Richard O’Sullivan, and Flavia M. Cicuttini, Arthritis Care & Research, October 2007; (DOI: 10.1002/art.22990).
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