Question: I understand that running, swimming and other endurance exercises can help treat depression. Can working out on weight machines do the same thing? Answer: An extensive literature (perhaps a thousand or more studies) clearly indicates that for many normally healthy people, exercise has an antidepressant effect. That is, regular, moderately vigorous activity tends to reduce stress and anxiety and increase one's general feeling of well-being. As you suggest, most of the research supporting this has focused on endurance activities. But several recent studies have considered weight training, and the results have been similar.
These psychological benefits are attributed to factors ranging from improved self image to an exercise-induced release of endorphins (morphine-like substances produced by the brain, pituitary gland and other tissue). Or, it may simply be, as some psychologists suggest, that exercise provides a healthy distraction from the daily grind of making a living, taking care of a home or getting an education. Whatever the reason for the pay-off, there is little doubt that most of us feel pretty good after a hard workout _ and this alone often makes it worth the effort.
It's important to stress that a key phrase in this answer is "normally healthy people." In terms of clinical depression, the therapeutic effects of exercise are not clear. And the value of exercise in such cases is sometimes stretched well beyond the available data.
Red meat and health
Question: When my son came home from college for the summer he announced that he has stopped eating red meat, and that his father and I should do the same. Our informed freshman says that red meat causes colon cancer, particularly in older folks. It seems that every time I turn around, I'm told not to eat something because it causes this or that. Does red meat really cause colon cancer?
Answer: Studies suggest that regularly eating red meat may increase the risk of developing colon cancer. In countries such as Japan and Greece, where inhabitants eat much less red meat than we do, the incidence of colon cancer is comparatively low. Also, American groups who traditionally eat little or no red meat, such as Seventh Day Adventists (most are vegetarians), have fewer occurrences of colon cancer. In addition, a study published recently in the New England Journal of Medicine that followed over 120,000 nurses for 15 years, found that the female nurses who ate red meat every day had more than twice the colon cancer risk of women who ate it less than once a month.
In spite of this evidence, it's really not necessary to give up red meat altogether. Beef, pork and lamb are very nourishing, and no one has shown that it will do you any harm _ in moderation. The U.S. Department of Agriculture, which is responsible for educating the public about nutrition, recommends that we eat only two to three servings of meat a day (that's all meat, including fish and chicken). You may want to go even further and limit your red meat consumption to one or two servings a week, as some nutritionists suggest.
Your son is correct about the incidence of colon cancer increasing with age _ beginning at age 40 and peaking at 60 to 75. This disease kills about 600,000 Americans each year. So, in addition to monitoring your diet, have regular rectal examinations.
Write with questions to Dr. Patrick J. Bird, Dean of the College of Health and Human Performance, University of Florida, Gainesville, Fla. 32611.
The Health & Fitness pages are coordinated by Jim Melvin. Comments may be addressed to: Jim Melvin, St. Petersburg Times, Floridian, P.O. Box 419, St. Petersburg, Fla. 33731-0419.