Physical inactivity is debilitating to the human body. Humans illustrate the biological dictate, “Use it or lose it.” That which we use becomes stronger, while that which we do not use becomes weaker. All body systems and all muscles, including the heart muscle, respond to this principle.
The results of a number of important investigations have concluded that physical inactivity is a major risk for heart disease. Those who exercise consistently, even at low intensity, tend to be healthier and to live longer than people who are sedentary. The ongoing Harvard Alumni Study found that the minimum exercise threshold for increasing longevity was as little as walking 5 miles per week. Those who walked or jogged 20 to 22 miles per week achieved optimal benefits. They lived an average of 2 years longer than sedentary people.
Investigators at the Cooper Institute for Aerobics Research found that physically fit subjects who had high blood pressure or elevated serum cholesterol were less likely to die prematurely from all causes than unfit individuals with normal values of both. The Centers for Disease Control and Prevention concluded that exercise is the one lifestyle change that could most affect health status. This is based primarily on the fact that more than 60 percent of Americans are either sedentary or they exercise too infrequently to enhance their health.
Health enhancement through physical activity does not require a great deal of effort. The requirement is 30 minutes of physical activity at least 4 days per week every week. There are few constraints on the type of activities that can be chosen. All physical activities (including cycling, jogging, walking, and swimming, among many others), most games and sports, many leisure-time activities, and some occupational work have the potential to meet the minimum criteria for improving health. Exercise, in sum, has the following cardiovascular benefits:
1. Increases HDL-cholesterol
2. Decreases LDL-cholesterol
3. Favorably changes the ratios between total cholesterol and HDL, and between LDL and HDL-cholesterol
4. Decreases triglyceride levels
5. Promotes relaxation; relieves stress and tension
6. Decreases body fat and favorably changes body composition
7. Reduces blood pressure, especially if it is high
8. Makes blood platelets less sticky
9. Results in fewer cardiac arrhythmias
10. Increases myocardial efficiency
11. Increases oxygen-carrying capacity of the blood
Exercise on a regular basis has been emphasized because it is the only way to improve fitness and health simultaneously. Another important reason for consistent participation in exercise is that it reduces the risk of sudden death from a heart attack during and immediately after sporadic physical exertion (such as shoveling snow).
Two studies, one completed in the United States and the other in Germany, documented this observation. The U. S. study showed that sedentary people were 100 times more vulnerable to incurring a heart attack during strenuous activity than at other times. In contrast, those who exercise consistently face only a small increase in the risk, but the health and fitness benefits from training far outweigh the minimal risk.
