Punch line: Medical experts are offering an additional reason to exercise: Regular workouts may help fight off colds and flu, reduce the risk of certain cancers and chronic diseases and slow the process of aging.
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Excerpted from WSJ: The Hidden Benefits of Exercise, Jan. 5, 2010
Physical activity has long been known to bestow such benefits as helping to maintain a healthy weight and reduce stress, not to mention tightening those abs. Now, a growing body of research is showing that regular exercise—as simple as a brisk 30- to 45-minute walk five times a week—can boost the body’s immune system, increasing the circulation of natural killer cells that fight off viruses and bacteria. And exercise has been shown to improve the body’s response to the influenza vaccine, making it more effective at keeping the virus at bay.
“No pill or nutritional supplement has the power of near-daily moderate activity in lowering the number of sick days people take.”
The Centers for Disease Control and Prevention says 36% of U.S. adults didn’t engage in any leisure-time physical activity in 2008.
“We need to refocus the national message on physical activity, which can have a bigger impact on health than losing weight.”
Regular exercise has been shown to combat the ongoing damage done to cells, tissues and organs that underlies many chronic conditions. Indeed, studies have found that exercise can lower blood pressure, reduce bad cholesterol, and cut the incidence of Type 2 diabetes.
Scientific studies are now suggesting that exercise-induced changes in the body’s immune system may protect against some forms of cancer.
Studies suggest that women who exercise regularly can expect a 20% to 30% reduction in the chance of getting breast cancer compared with women who didn’t exercise. Walking the equivalent of three to five hours per week at an average pace reduced the risk of dying from the disease by 50% compared with more sedentary women.
Researchers are also investigating whether exercise can influence aging in the body. In particular, they are looking at whether exercise lengthens telomeres, the strands of DNA at the tips of chromosomes. When telomeres get too short, cells no longer can divide and they become inactive, a process associated with aging, cancer and a higher risk of death.
Studies have concluded that physical activity has an anti-aging effect at the cellular level, suggesting exercise could prevent aging of the cardiovascular system.
“Exercise can be used like a vaccine to prevent disease and a medication to treat disease … If there were a drug with the same benefits as exercise, it would instantly be the standard of care.”
Starting an exercise program can have benefits at any age, but is particularly important for those over 40, when physical strength, endurance, flexibility and balance begin to decline.
During exercise, two types of immune cells circulate more freely in the blood, neutralizing pathogens. Although the immune system returns to normal within three hours, the effect of the exercise is cumulative, adding up over time to reduce illness rates.
But, high-intensity exercise over long periods, like running a marathon, can “take a good thing too far.” Such exertion can induce the release of stress hormones in the body that damp some functions of the immune system temporarily, increasing susceptibility to infection for short periods. In one five-year study, one out of four ultra-marathoners reported sickness in the two weeks following their races.
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