It's that time of year when resolutions are on people's minds. As we all know, one of the most common New Year's resolutions is to exercise--often for the stated purpose of losing weight. But exercise is good for so much more. For those who want to keep score, here's a quick tabulation of the documented health benefits of exercise.
Cardiovascular Benefits of Exercise
Lower blood pressure. There is ample evidence that physical activity is associated with lower blood pressure measurements in the general population. Moreover, exercise can be used to reduce the blood pressure (by 5-15 mm Hg) among those with high blood pressure (hypertension). In fact, an exercise program is often a component of the initial treatment of those with borderline or newly diagnosed hypertension.
Better cholesterol profile. Moderate amounts of exercise favorably affect the lipid profile by lowering the LDL ("bad") cholesterol, total cholesterol, and triglycerides and by increasing the HDL ("good") cholesterol. This more favorable lipid profile is associated with reduced risk of coronary artery disease (CAD).
Less chance of stroke. Although there has been conflicting evidence over the years, it is now generally accepted that moderate and high levels of exercise are associated with reduced risk of most types of stroke.
Maintaining an appropriate weight. I'm listing this benefit among the cardiovascular benefits because it is so intertwined with these benefits. Exercise is associated with less obesity and a lower prevalence of metabolic syndrome (a collection of problems such as diabetes, high blood pressure, and abnormal lipid profile).
Other Benefits of Exercise
People who exercise live longer. It doesn't get much better than that! Given the cardiovascular benefits mentioned above, this isn't surprising. It's true for men and women, for smokers or nonsmokers, for the lean or overweight, and for those who are otherwise healthy or not.
In a study of middle-aged men in Sweden who were studied prospectively for a period of 20 years, investigators found that, after controlling for other relevant variables, work-related or leisure-time physical activity was associated with a protective effect on the death rate due to coronary heart disease (CHD), cancer, and, in fact, all causes.
Less chance of cancer. The National Cancer Institute reports that there is very strong evidence that physical activity is associated with reduced risk for colon and breast cancer. Although the data are not conclusive, studies have also shown that there is probably a reduced risk of endometrial (uterine), lung, and prostate cancers as well.
Increased muscle strength. Perhaps this is obvious; it takes muscles to exercise. This benefit is likely more pronounced with resistance than aerobic exercise.
Better immune system. There is accumulating evidence that moderate exercise improves the body's immune system--its ability to fight off colds and infection. The underlying mechanisms are still being investigated. This is a double-edged sword, though. Studies have also shown that "too much" exercise may lead to the opposite effect.
Less diabetes. Adult-onset, or type 2, diabetes mellitus is associated with obesity and a sedentary lifestyle. Those who are physically active are much less likely to develop diabetes. Moreover, a moderate program of exercise is often prescribed as an effective intervention to prevent the development of diabetes among individuals who already show signs of glucose intolerance. Exercise is known to reduce blood sugar levels and to improve the body's handling of insulin.
Better learning and memory. It has been shown that adults who exercise perform better on tests of memory, decision-making, and problem solving. The underlying mechanisms are still being studied, but exercise may increase blood flow to regions of the brain that are particularly involved in these cognitive skills. There is also preliminary evidence, at least in animal models, that physical activity may stimulate the growth of new brain neurons that may be involved in learning and memory.
Better sexual function. There is ample evidence that the incidence of erectile dysfunction is less among men who exercise. Moreover, sexual function and enjoyment are improved among individuals who avoid the problems of the metabolic syndrome, obesity, and diabetes--all of which can be mitigated by exercise.
Less osteoporosis. Especially among older women, continued exercise can help avoid the problems of osteoporosis (loss of bone density) and chronic back pain.
Better sleep. The relationship between exercise and sleep has been studied extensively. In many patient groups, those who exercise have less insomnia and better quality of sleep.
Better mental health. Lastly, there's been increasing awareness and investigation of the mental health benefits of exercise. In a commonly mentioned study, researchers at Duke University found that among 202 individuals suffering from major depression who were treated for 16 weeks, 60% of participants who exercised for 30 minutes three times each week (and received no anti-depression medication) saw improvement in their depression symptoms--the same percentage as for those who used medication(s) alone.
I find almost universally among my athlete friends the opinion that exercise makes us "feel better." That observation is borne out in the various scientific studies that have shown that even small amounts of exercise have been associated with incresed happiness, better energy levels and confidence, and decreased anxiety and tension.
How Much Exercise is Needed?
We've all heard the adage that "if some's good, more's better." That's likely true for exercise, too, at least to some reasonable extent. We'll leave for another day the discussion about the potential adverse effects of too much exercise. But how much exercise is needed to enjoy the good benefits? I'll bet there's no exact amount for any single individual. If the truth were known, there are probably benefits that begin to accrue with even the first few minutes of exercise. After review of the available accumulated evidence, the American Heart Association (AHA) has formulated recommendations for both children and adults. Regarding physical activity and children, the AHA has adopted the following Scientific Position:
"Physical inactivity is a major risk factor for developing coronary artery disease. It also increases the risk of stroke and such other major cardiovascular risk factors as obesity, high blood pressure, low HDL ("good") cholesterol and diabetes. The American Heart Association recommends that children and adolescents participate in at least 60 minutes of moderate to vigorous physical activity each day."
Using similar reasoning, the AHA has adopted the following Scientific Position regarding physical activity in adults:
"Physical inactivity is a major risk factor for developing coronary artery disease. Coronary artery disease is characterized by deposits of fatty substances, cholesterol, calcium, and other substances in the inner lining of arteries that supply blood to the heart muscle. It also contributes to other risk factors, including obesity, high blood pressure, high triglycerides, a low level of HDL ("good") cholesterol and diabetes. Even moderately intense physical activity such as brisk wallking is beneficial when done regularly for a total of 30 minutes or longer on most or all days."
I suspect that most readers here have embraced exercise and made it part of their daily and weekly routine. Most of us have come to recognize a final benefit of exercise--it's fun! This is the time of year when a few encouraging words might help a friend, family member, or co-worker stick with their New Year's resolution to exercise. Look for that opportunity.
Happy New Year!
