As millions of Americans flock to the gym armed with New Year’s resolutions to get in shape, 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.
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.
Medical experts say inactivity poses as great a health risk as smoking, contributing to heart disease, diabetes, hypertension, cancer, depression, arthritis and osteoporosis. The Centers for Disease Control and Prevention says 36% of U.S. adults didn’t engage in any leisure-time physical activity in 2008.
Even lean men and women who are inactive are at higher risk of death and disease. So while reducing obesity is an important goal, “the better message would be to get everyone to walk 30 minutes a day” says Robert Sallis, co-director of sports medicine at Fontana Medical Center, a Southern California facility owned by managed-care giant Kaiser Permanente. “We need to refocus the national message on physical activity, which can have a bigger impact on health than losing weight.”
Building on that earlier research, scientific studies are now suggesting that exercise-induced changes in the body’s immune system may protect against some forms of cancer. For example, Harvard Medical School’s consumer Web site (hms.harvard.edu/public/consumer) notes that more than 60 studies in recent years taken together 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. While researchers are still studying the molecular changes caused by exercise and how they affect cancer, the studies suggest the outcome could be due to exercise’s ability to lower estrogen levels.
One study of 3,000 women being treated for breast cancer, published in the Journal of the American Medical Association, showed that for those patients with hormone-responsive tumors, 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.
In a study published in November in Circulation, the medical journal of the American Heart Association, German researchers compared two groups of professional athletes (32 of whom were in their early 20s, and 25 who were middle-aged) with two groups (26 young and 21 middle-aged) who were healthy nonsmokers, but not regular exercisers. The athletes had significantly less erosion in telomeres than their more sedentary counterparts. The study concluded that physical activity has an anti-aging effect at the cellular level, suggesting exercise could prevent aging of the cardiovascular system.
Dr. Court’s Comments:
To summarize, exercise can boost your immune system, decrease your risk of cancer and slow the aging process. That’s great news. I have many patients who ask me what can they do to reduce their risk of disease. Along with a healthy diet and supplement regime, I always recommend exercise. The benefits of exercise seem to be endless. As human beings, we were not designed to be sedentary. We evolved to move and be physical. To think that being a couch potato is not going to have an effect on overall well being, not just cardiovascular health, is naive.