Why should one exercise? What are the benefits of exercise? The multitude of reasons includes increase in strength, increase in flexibility, and increase in cardiorespiratory endurance. Exercise also can help to keep us lean, improve our self-image, and give us a sense of general well-being. These reasons can be documented, but to many nonexercising adults, none of these reasons are enough to induce them to exercise. They rationalize that none of these reasons contribute to becoming successful, wealthy, or even more productive. To be more convincing, other benefits of exercising can be incorporated into the list, such as the fact that becoming physically fit enables us to perform better in life's activities such as playing tennis, golfing, swimming, cycling, mountain climbing, or running marathons. However, many nonexercisers who do not participate in any of these activities and are more inclined towards reading, playing bridge, administering and operating businesses or organizations, or being involved with politics continue to be unconvinced. So what does exercise offer these sedentary individuals?
The leading cause of death in the United States is heart disease. More than a million people will die of some form of heart disease this year. However, when the media reports how many people needlessly lose their lives in traffic accidents and that, in some years, more than 60,000 people are killed on the highways, we seem to find this much more frightening. But as devastating as that number is, it is really nothing when compared with the million people who die from heart disease. Heart disease kills 16 to 20 times the number of people killed in traffic accidents. But this fact doesn't seem to concern us as much as traffic accidents.
Heart disease is no longer a disease of old age; it is a disease that affects young adults as well. Studies were done by medical researchers during the Korean War and later during the Vietnam War that involved performing autopsies on very young GIs who were killed during those conflicts. The autopsies showed that in more than 70% of these young men, early signs of developing coronary heart disease were already evident.
The sudden heart attack that is experienced by the 40-year-old man didn't just happen; the degenerative process of the heart and coronary arteries began when the man was in his 20s. Years ago, the scientific literature began indicating that heart disease has a 20-year incubation period. Incubation period? Normally, incubation periods have been associated with communicable diseases. For example, a young boy plays with a neighbor child who has measles, and then 7 to 14 days later, the boy has measles. Those 7 to 14 days are the incubation period for measles. Heart disease is not a communicable disease, but it is a disease that results from a degenerative process that focuses on the coronary arteries. However, that degenerative process may take 10 to 20 years to develop to the point when a coronary accident occurs. So coronary heart disease may well be said to have an incubation period of approximately 20 years.
Therefore, an intervention program to reduce the incidence of heart disease needs to be started when one is young. Heart disease does not have simple beginnings: many factors contribute to the degenerative process that later results in the coronary arteries narrowing or closing completely. The American Heart Association (AHA) has identified these factors and labeled them coronary risk factors (CRF), and has successfully educated the population about the CRF and how they can be minimized or eliminated. Although these risk factors are familiar to most of the adult population, they are important to reiterate (1, 2).
Many individuals, from all walks of life, suffer from elevated blood pressure. High blood pressure makes a significant contribution to the development of coronary heart disease (CHD); individuals with uncontrolled elevated blood pressure have almost three times the risk of developing CHD than individuals with normal blood pressure (1). Today's medicine can control blood pressure.
Dietary fats are energy-rich substances that provide fuel and energy for many body processes. However, dietitians have warned us that the U.S. diet is too high in fat, especially animal fat. Fats in the body are called lipids, which are eaten or formed by the body, mainly in the liver, and are stored in fat cells. Fat is desirable and is used for insulation and protection. However, when the amount of fat stored in the body is in excess, it becomes a health problem. Two major lipids that affect CHD are cholesterol and triglycerides. In the blood, cholesterol attaches to protein and is transported as lipoproteins. Three of these lipoproteins are very low-density lipoproteins (VLDL cholesterol), low-density lipoproteins (LDL cholesterol), and high-density lipoproteins (HDL cholesterol). The names of these lipoproteins include the word density because the early methods of measuring cholesterol involved high speed centrifuging, and the cholesterol migrated because of its density (weight). Each of these lipoproteins serves a different function in the body, and the body regulates the lipoprotein levels either by reducing the manufacture of them or by decreasing or increasing their rate of removal. Abnormally high levels of certain cholesterols (primarily LDL) increase the risk of CHD because LDL is deposited on the walls of arteries. Individuals who have elevated total cholesterol levels more than double their risk of CHD.
Stress is another important risk factor. There are primarily two kinds of stress. The first kind is induced by one's personality-that is, when an individual is a stressful type of person (referred to as a Type A personality). This basic personality is stressful, and these individuals tend to "put themselves under stress" in most situations: driving, walking, working, and just living. The second type of stress is situational; for example, air traffic controllers are often identified as individuals who are in stressful situations. Keeping aircrafts separated around a busy airport with hundreds of passengers in dozens of planes puts the responsible air traffic controller under a great deal of stress. It has been shown that either kind of stress increases the risk of heart disease.
Being overweight, and especially being obese, increases the risk of heart disease. Individuals who are obese have twice the incidence of high blood pressure and three times the risk of heart disease. Obesity was recently classified as a disease by the U.S. Centers for Disease Control and Prevention (CDC).
Sedentary individuals have a greater risk of CHD than physically active individuals (1-4). Several studies have shown that regular exercise protects individuals from heart disease; however, this fact has not been stressed enough by the medical community (3, 5-8). Many of these studies have presented excellent data to indicate that not only does regular exercise protect us against heart disease, but it also beneficially affects several of the other coronary risk factors. Exercise is well accepted as being necessary for dieting and weight loss to be successful. Data also indicate that regular exercise reduces elevated blood pressure. Several studies indicate that regular exercise lowers elevated total cholesterol. More importantly, exercise elevates HDL cholesterol, which is the "good" cholesterol (9).
A longitudinal study of men participating in a 5-day-per-week supervised exercise program showed several changes that occurred in subjects who have participated for several years (9). It is generally assumed by gerontologists that muscular strength decreases with age. However, when individuals exercise regularly, this is not true. Figure 1 shows the changes that occurred in upper body strength, as measured by the bench press, in men who exercised regularly for 20 years. It also must be noted that when these men were measured after 20 years of being in the study, they also were 20 years older, making the data even more significant. The men improved the most during the first year of exercise, but their strength remained high for the balance of the 20 years.
Figure 2 compares the upper body strength of men who were participating in the exercise study with a sample from the general population (10). The "Fit Group" is comprised of the men in the longitudinal exercise study, and the general population is labeled appropriately. It should be noted that after 20 years, the strength of the 65-year-and-older group was slightly better than 20-year-old individuals in the general population. These results were equally true for the strength tests involving arm curls and abdominal crunches, as well as for measures of flexibility (9).
Obesity is a major national health problem. The amount of body fat in the subjects participating in the longitudinal exercise study decreased in men who exercised regularly, even without concomitant dieting (Figure 3). During the first year of exercise, the men reduced body fat significantly from 28% to 19%, then during the ensuing years the percentage of fat remained low (9).
Figure 4 presents the body fat changes in the men in the exercise study compared with the general population. In the general population, the amount of body fat increased steadily from approximately 15% in 18-year-old individuals to 28% in the 65-year-old individuals. However, those in the exercise study who exercised daily for 20 years only increased from 15% fat to 19% (9). Regular exercise helps to maintain low body fat levels.
Figures 1 through 4 support the benefits of regular exercise on a variety of fitness variables, but what about other factors that play an important role in CHD? What about total cholesterol levels, and particularly HDL cholesterol, which actually protects one against CHD?
Figure 5 shows the changes in total cholesterol in the men who were in the longitudinal exercise study. The subjects were primarily upper-socioeconomic business and professional men and began the exercise study with slightly elevated total cholesterol levels, approximately 248 mg/dL. At the end of one year of exercise, this was reduced to 200 mg/dL, and 27 years later, even though they were 27 years older, their total cholesterol was 170 mg/dL. This clearly demonstrates that regular exercise will reduce and keep total cholesterol low (9).
Figure 6 presents the changes in the HDL cholesterol in the longitudinal exercise study. Whereas LDL can be changed by diet, HDL is more difficult to change. It has now been shown that HDL increases with regular exercise. Figure 6 shows that the subjects began the exercise program with an HDL cholesterol level of 35 mg/dL, and at the end of the first year of exercise, HDL had increased to 55 mg/dL. Twenty-seven years later, their HDL was 60 mg/dL (9).
Perhaps the normally identified benefits of exercise, namely increased strength, flexibility, aerobic fitness, and body leanness, will not motivate the chronically sedentary individual to start exercising, but one can only hope that preventing heart disease and living longer and better will impress them. No one wants to die, especially early. We owe a long and good life to ourselves, our families, our children, and our friends.
Exercise does not have to be boring, objectionable, or a waste of time. To many, exercising means lifting weights, getting muscularly sore, sweating, and feeling tired and uncomfortable. This is not necessarily so; for example, walking is an enjoyable and mind-clearing activity. Getting up 30 minutes earlier in the morning and going outside and walking for 30 minutes is a great exercise. It clears the head for the day; the day's plans and activities can be organized, and there is quiet time to think. I know a married couple who were having serious marital problems. Both were overweight and both decided to walk for 30 minutes every morning, and they decided to walk together. During their walks they began to talk, discuss, and solve many of their differences. Walking literally saved their marriage. Walking also can be done in the evening or during the normal lunch period. It's easy, pleasant, and beneficial.
Some individuals have never experienced the feeling of being physically fit, and do not know what it's like to feel healthy and energetic. Once they experience it, further exercise becomes much more attractive and desirable.
Why should we exercise? To live better!
Condensed Version and Bottom Line
It is estimated that 80% of the population is not adequately physically active. Informing nonexercisers that exercise will improve flexibility, strength and muscular endurance, and aerobic fitness has not motivated them to exercise. Everyone wants to be free of disease and live longer. There is available research information that indicates that those who exercise regularly improve their quality of life, live longer, and prevent coronary heart disease. Stressing the health benefits of exercise may be more successful in getting sedentary individuals to exercise.
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. Champaign IL: Human Kinetics, 2000.