all exercise stories

Too much water can be life-threatening for marathoners

Tue, 10 Jul 2007 12:43:55 -0400

Runners who consume too much water or sports drinks during a marathon can develop a life-threatening condition called exercise-associated hyponatremia (EAH). Beyond drinking, however, researchers at Harvard-affiliated McLean Hospital report in the May 2007 issue of the American Journal of Medicine that this complication during endurance exercise is also the result of a hormonal stress response, which decreases urine formation and prevents the excretion of excess water.

Humans hot, sweaty, natural-born runners

50443248 — Tue, 02 Oct 2007 15:39:11 -0400

Hairless, clawless, and largely weaponless, ancient humans used the unlikely combination of sweatiness and relentlessness to gain the upper hand over their faster, stronger, generally more dangerous animal prey, Harvard Anthropology Professor Daniel Lieberman said Thursday (April 12).

Just days before Monday’s 111th running of the Boston Marathon, Lieberman presented his theories of the importance of running to ancestral humans to explain why we’re the only species that voluntarily runs extraordinarily long distances, such as the 26.2 miles in the marathon.

Marathon running can damage a heart

Wed, 11 Jul 2007 14:56:27 -0400

Running 26.2 miles is not for the faint of heart.

Abnormalities in heart structure and function were found in men and women who ran the Boston Marathon in 2004 and 2005 by Harvard Medical School researchers.

For some 2,500 years, scientists have written about possible unhealthy outcomes of running for tens of miles when nothing is chasing you. But more and more people are doing it. In 2005, 382,000 runners completed a marathon, 80,000 more than in 2000. That has not led to a massive increase in heart attacks. In fact, Arthur Siegel, an assistant clinical professor of medicine, says the risk of dying from a heart attack is a scant one in 50,000 runners.

Exercise boosts health of HIV-infected women

Thu, 12 Jul 2007 16:41:57 -0400

Betsy Lincoln felt pregnant all the time. Loss of muscle tone in her face, arms, and legs made her look so bad, she didn't want to leave her apartment. She had little strength or endurance. Lifting one of her children or climbing a flight of stairs exhausted her.

Lincoln (not her real name) is representative of many of the estimated 250,000 women in the United States infected with HIV (human immunodeficiency virus), or the deadly AIDS it causes. And that number is rising. In this country, most of the women are minorities and poor, with limited access to medical care. Recent research also suggests that they may be at increased risk for heart disease. Even the drugs they take to keep their infection under control can cause unwanted changes in body fat and loss of energy.

Exercise cuts risk of sudden cardiac death

70652986 — Mon, 26 Mar 2007 06:25:47 -0400

Exercise improves your health, but can you kill yourself with too much snow shoveling, yard work, jogging, or playing tennis?

"Despite all of the known benefits of exercise, there are also well-documented associations between acute episodes of exertion and sudden cardiac death," notes Christine Albert, an assistant professor of medicine at Harvard Medical School. "Although relatively rare, these deaths commonly occur in an unexpected fashion among those who appear quite healthy."

In the largest study ever done to get a better handle on this question, Albert and her colleagues followed the exertions of almost 85,000 women for 24 years, while keeping track of their hearts. The women, selected from an ongoing study of registered nurses known as the Nurses Health Study, were between 34 and 59 years old in 1986. From then until 2004, the women filled out questionnaires about how much time they spent jogging, running, bicycling, swimming, playing tennis or squash, and undertaking other activities that require moderate to vigorous exertion.

"To our knowledge, this analysis is the first to assess both the transient and long-term risk of sudden cardiac death associated with physical activity among women," says Albert, senior author of the study and also director of the Center for Arrhythmia Prevention at the Harvard-affiliated Brigham and Women's Hospital in Boston. Results of the study appeared in the March 22/29, 2006 Journal of the American Medical Association's theme issue on Women's Health.

The findings are encouraging. Out of almost 85,000 women, only nine died while doing yard work, housework, swimming, or physical therapy. To put this in numbers, as scientists always like to do: Their investigation covered 1.93 million person years of exercise and recorded only one death for each 36.5 million hours of exertion. In other words: Sudden cardiac death during exertion is an extremely rare event in women.

And there's still more good news. Regular exercise may significantly minimize this small risk, in both the short and long term.

Exercise shown to promote breast cancer survival

50443248 — Tue, 24 Jul 2007 11:15:24 -0400

Exercise plays a role in preventing breast cancer, and research strongly suggests that breast cancer patients who are more physically active improve their self-esteem and body image. Now, a landmark study from the Brigham and Women's Hospital (BWH) finds that exercise after diagnosis may help breast cancer patients live longer. The study appears in the May 25 issue of the Journal of the American Medical Association.
According to lead author BWH researcher Michelle D. Holmes, "It is well established that exercise plays an important role in preventing many diseases, including breast cancer. However, we found that women who are physically active after breast cancer diagnosis may lower their risk of death from breast cancer and cancer recurrence."

Study finds that both weight and exercise are key to longevity

70652986 — Mon, 26 Mar 2007 05:38:51 -0400

Over 115,000 participants who were free of cardiovascular disease or cancer, who were between the ages of 30 and 55 and had filled out biennial health and lifestyle questionnaires between 1976 and 2000, were chosen for the study from the Brigham and Women's Hospital-based Nurses' Health Study. The women answered questionnaires that asked on average how much time was spent per week on moderate physical activities and vigorous physical activities. Women who spent 3.5 hours per week or more exercising were considered physically active. The researchers found that both obesity and physical activity significantly and independently affected mortality. A high level of physical activity did not eliminate the risk of premature death associated with obesity and leanness did not counteract the increased risk in mortality conferred by inactivity. Compared to physically active, lean women, there was nearly a two-and-a-half- fold increase in risk of death for inactive and obese women. The researchers estimated that excess weight (BMI over 25) and physical inactivity accounted for 31 percent of all premature deaths among the study participants with 59 percent of the deaths attributable to cardiovascular disease and 21 percent from cancer among the non-smoking women. "It is clear that both weight and exercise are important for health and longevity," said Frank Hu, lead author of the study and an associate professor of nutrition and epidemiology at the Harvard School of Public Health.

Sudden death among military personnel often caused by exercise and an identifiable cardiac abnormality

70652986 — Mon, 26 Mar 2007 06:19:53 -0400

According to the study's lead author BWH's Robert E. Eckart, D.O., they had expected that most of the sudden deaths would stem from structural heart abnormalities, but that in actuality, a large number of the deaths defied this theory and could not be identified by today's screening methods. "The findings suggest genetic abnormalities that affect the heart's electrical system are likely to be a significant cause of death."

Researchers reviewed cases of 126 non-traumatic sudden deaths that occurred among 6.3 million military recruits, male and female, aged 18 to 35 years from 1977 through 2001. After examining medical records of the 126 cases, researchers found that most individuals did not suffer from structural abnormalities of the heart that might have shown up during physical examination or an echocardiogram. Instead, researchers found that 86 percent of the sudden deaths were related to exercise. In addition, researchers found after autopsy that while 51 percent of the deaths were caused by one of many potential cardiac abnormalities, the single leading cause of sudden death in this population was a structurally normal heart. The cardiac abnormalities identified most frequently included coronary artery abnormalities, followed by inflammation of the heart muscle and an enlarged muscular wall of the heart that can block normal blood flow during heavy exercise.

Walking improves cognitive functions in older women

70652986 — Mon, 26 Mar 2007 05:35:24 -0400

In a study, elderly women who engaged in the most activity -- for example, walking at least 6 hours per week -- had a 20 percent decrease in risk of cognitive impairment compared to those who were inactive. they also demonstrated the cognitive functioning of someone three-years younger than their actual age. The findings were published in the Sept. 22, 2004, issue of the Journal of the American Medical Association. “Walking is a popular, accessible and inexpensive activity for older adults that appears to provide many health benefits. In addition to studies showing a reduced risk of heart disease, pulmonary disease and diabetes, a moderate level of walking also appeared to reduce the rate of cognitive decline in our study,” said lead author Jennifer Weuve of the Harvard School of Public Health. “What is most striking is that for older women who are able to engage in several hours per week of physical activity, their cognitive function seemed to be comparable to that of a woman several years younger.” Researchers analyzed the data from 18,766 U.S. women, aged 70 to 81 years, from the Nurses' Health Study.

Study finds leptin plays a key role in women's health

70652986 — Mon, 26 Mar 2007 07:10:15 -0400

Senior author Christos Mantzoros, M.D., director of the Human Nutrition Research Unit and clinical research overseer of the Department of Endocrinology at BIDMC and associate professor of medicine at Harvard Medical School explains that the three groups of women who can most benefit from this study are very thin women who are infertile, serious athletes and dancers in danger of bone loss, and women with eating disorders. What these women have in common is their extremely low levels of body fat.

Leptin functions to signal the brain and other organs about dangerous states of very low energy availability. In so doing, he adds, leptin regulates several key physiological functions that depend on adequate energy balance.

Consequently, Mantzoros adds, in situations in which body fat is severely diminished, a woman's body enters a state harmful to her reproductive and metabolic health.

To test leptin's ability to restore positive energy balance, the researchers recruited 14 competitive female athletes, all of whom had been diagnosed with amenorrhea.

Eight of the 14 subjects received doses of leptin that raised their levels to normal. Six subjects served as controls, receiving no treatment.

Mantzoros says the leptin therapy restored the women's reproductive activity to normal and improved the women's bone density. The control group showed no change in their condition.

Dramatic gains shown with moderate weight loss, exercise

70652986 — Mon, 26 Mar 2007 05:34:19 -0400

A study of 35 obese people included three groups of volunteers; all were obese and had a body mass index above 30 kg/m2 and had insulin resistance. The first group in the study did not have diabetes; the second group had a condition known as impaired glucose tolerance and was at high risk for developing diabetes; and the third group had type 2 diabetes. The three groups were put on a calorie-restricted diet, simply by cutting 500 caloriesfrom their daily caloric consumption. The participants also exercised in the gym at Joslin Diabetes Center in Boston two to three times per week. Exercise was moderate in intensity and for 30 minutes each session. “After 6 months, the study participants had lost an average of about 7 percent of their initial weight or approximately 16 pounds in a 220-pound person,” researcher Osama Hamdy said. The researchers found significant improvement in the function of the major blood vessels; the risk of developing arteriosclerosis and heart disease was reduced, Hamdy said. The study was published in Diabetes Care.

Generous portions of TV make women fat

70652986 — Mon, 26 Mar 2007 05:29:10 -0400

The first study to compare the effects of inactivity on obesity and diabetes concludes that being a couch potato significantly raises the risk of both diseases. "Our data provide strong evidence that sedentary behaviors, especially prolonged TV watching, are directly related to the risk of obesity and type 2 diabetes," reports Frank Hu, leader of a team from the Harvard School of Public Health and the Harvard Medical School that did the research. "In contrast, even light to moderate activity, such as walking and housework, substantially lowers the risk." Previous studies have shown that children who watch too much TV gain too much weight. A different Harvard investigation, called the Health Professionals Follow-up Study, found a positive link between heavy TV viewing and type 2 diabetes.

Specific types of exercise can significantly reduce risk of heart disease among men

70652986 — Mon, 26 Mar 2007 05:24:12 -0400

A pool of 44,452 men from the Health Professionals' Follow-Up Study were monitored via questionnaire every two years from 1986 to 1998 to determine potential coronary heart disease risk factors and type and intensity of leisure time activity. While studies have been conducted on the beneficial relationship of exercise and risk of CHD, there is a scarcity of information on what role exercise type and intensity level play in reducing CHD risk. Researchers found that men who trained with weights for 30 minutes or more per week reduced their risk for CHD by 23 percent compared to those who didn't train with weights.

Cardiovascular risks seen from marathon running

70652986 — Mon, 26 Mar 2007 05:16:18 -0400

Researchers analyzed the blood of marathon runners less than 24 hours after they had finished a race. They found abnormally high levels of inflammatory and clotting factors of the kind that are known to set the stage for heart attacks. "My concern is for people who exercise thinking 'more is better,' and that marathon running will provide ultimate protection against heart disease," said Arthur Siegel, director of Internal Medicine at McLean Hospital in Belmont, Mass., and an assistant clinical professor of medicine at Harvard Medical School. "In fact, it can set off a cascade of events that may transiently increase the risk for acute cardiac events." That doesn't mean that runners should stop running marathons, "But it does mean we need to understand more about marathon training and how the human body reacts to stress," said Charles Schulman, president of the American Running Association and an assistant clinical professor of medicine at Harvard Medical School. "Dr. Siegel's research may lead us to conclude that running a marathon is not a panacea. In fact, coupled with poor or improper training, it could lead to consequences much more serious than just the usual running injury."

Determining colon cancer risk is becoming easier

70652986 — Mon, 26 Mar 2007 05:07:19 -0400

More than 50 percent of colon cancers can be prevented through lifestyle changes and regular screening tests. The lifestyle changes are the same ones that reduce your risk of heart disease and other cancers. Be more physically active by getting at least three hours a week of physical exercise. Eat less red meat and more fruit and vegetables. Cut alcohol consumption down to one to two drinks a day and take a daily multivitamin pill that contains folic acid. Most important of all is to get screened regularly after age 50, when most people develop colon cancer. The Harvard Center for Cancer Prevention provides risk evaluations not only for colon cancer but for breast, prostate, lung, bladder, skin (melanoma), uterine, kidney, pancreatic, ovarian, stomach, and cervical cancers online at http://www.yourcancerrisk.harvard.edu/