The Importance Of Exercise and How To Incorporate It Into Your Lifestyle
by Jeffry S. Life, M.D. Ph.D.
The United Nations, the World Health Organization, and 37 countries including the United States have proclaimed 2000-2010 as the Bone and Joint Decade to promote the importance of a healthy musculoskeletal structure for a lifetime. The number of people older than 50 will double between 1990 and 2020. Advances in medicine continue to make it possible for more people to live longer, but today most want to live stronger and maintain their quality of life. Each year, musculoskeletal conditions and injuries account for about 102.3 million visits to physician offices, 10.2 million hospital outpatient visits, 25 million emergency department visits, 3 million hospitalizations, and 7.5 million procedures, and they cost an estimated $300 billion.1
As the baby boom generation ages, people in their 50s begin to notice more aches and pains after performing the same activities that were painless in their 40s, and those in their 60s can't do as much as they did in their 50s. Roy Shephard, MD, PhD, professor emeritus of applied physiology at the University of Toronto, points out that, "Both aerobic power and muscle strength decline by as much as 10% for every decade of adult life, but a progressive exercise prescription can enhance function by 10% to 20%; thus, in terms of functional capacity, conditioning can reduce biological age by 10 to 20 years."2
In 1998, the American College of Sports Medicine issued its first position statement on aging and exercise,3 in which it recommended strength training for frail older people. Petrella says, "We now know that older patients can perform to very high levels, so exercise prescription does not differ for older and younger persons, and training effects for the elderly can exceed those of younger people at the upper end of VO2max."
Exercise is the key to maintaining quality of life, as well as extending the number of years of life expectancy. It's never too late to start, and an early start is better. Even 90- and 100-year-olds can do strength training.
Exercise is really a form of medicine that can prevent or treat many disabling or fatal diseases. Seventy percent of deaths (1.5 million) each year in the United States are a result of eight killers: heart disease, cancer, stroke, hypertension, chronic obstructive pulmonary disease (COPD), diabetes, and osteoporosis4. Other diseases treatable with exercise--obesity, arthritis, depression, and dyslipidemia--contribute considerably to disability and premature death
The health rewards of exercise extend far beyond its benefits for specific diseases. Exercise reduces blood clotting, enhances self-image, elevates mood, reduces stress, improves appearance, increases energy, gives the feeling of well-being (probably by stimulating endorphins). It reinforces other positive life-style changes, such as healthier eating habits and smoking cessation5. It also stimulates creative thinking 6.
Furthermore, the ability of exercise to restore function to organs, muscles, joints, and bones is not shared by drugs or surgery. Paradoxically, conventional medical practice favors physical rest and inactivity during recovery from illness.
Aerobic Exercise vs. Resistance Training
For many years doctors have advised middle-aged and older people to get plenty of aerobic exercise—that is, exercise that requires the rhythmic movement of their arms and legs. This form of exercise, which includes walking, jogging, swimming, bicycle riding and so on, has always been thought to be the best exercise to help prevent and/or treat heart disease. Doctors have traditionally discouraged people with heart disease or older people from engaging in strength training with weights or exercise machines because they believed that this would put dangerous stress on their hearts.
Recently, an expert panel of scientists, organized by the American Heart Association, has finally put to rest that age-old myth that weight training and other forms of resistance exercise are bad for the heart. In fact, this committee has advised doctors to actually start recommending this form of exercise for their healthy older patients, as well as those with heart disease, including some people with recent heart attacks as long as they are closely monitored and supervised by experienced health professionals.
Aerobic exercise and resistance training clearly work hand-in-hand to prevent, reduce, or even eliminate heart disease by preventing or controlling diabetes, high cholesterol and high blood pressure. Aerobic exercise does a great job lowering systolic blood pressure, and both aerobic and resistance exercise help reduce diastolic blood pressure. This makes it much easier for the heart to do its job of pumping blood throughout the body. Both forms of exercise also strengthen the heart muscle making it work much more efficiently.
Obviously, this is great news. Now doctors can encourage their patients with healthy hearts (no matter what their age or gender) and those with unhealthy hearts (under medical supervision) to start using resistance training along with their aerobic training as an integral part of their heart-disease prevention and/or treatment program.
The following table, by Pollock and Vincent, from The President’s Council on Physical Fitness and Sports Research Digest, is found in my article entitled “Why Everyone Should Lift Weights” in this website. This table helps us better understand the differences in aerobic (cardio) training and resistance training.
Comparison of the Effects of Aerobic Endurance Training to Strength (Resistance) Training on Health and Fitness Variables
Variable
Aerobic Exercise
Resistance Exercise
Increases Bone Density
Decreases Body Fat
Increases Muscle Mass very little effect
Increases Strength
Decreases Insulin Response to Glucose
Decreases Basal Insulin Levels
Increases Insulin Sensitivity
Increases HDL very little effect
Decreases Resting Heart Rate very little effect
Increases Stroke Volume of the Heart very little effect
Decreases Systolic Blood Pressure very little effect
Decreases Diastolic Blood Pressure
Improves Cardio/Vascular Fitness
Increases Endurance time
Improves Physical Function
Increases Basal Metabolism
Dr. Kenneth Cooper, who coined the term aerobics in 1968 and a staunch advocate of aerobic exercise, now believes a mix of aerobic conditioning and strength training is the best exercise program for aging adults. He proposes an “aerobic-strength axis” with the balance changing depending on how old you are. At age 40 and younger, he suggests 80% aerobics and 20% strength; age 41 to 50, 70/30; 51 to 60. 60/40; and at 61 and older, 55/45. So he still favors aerobics, but the bias practically disappears after age 60. “A good rule of thumb, “ says Cooper, “is that you should always include at least 50 percent aerobic/endurance work in your personal fitness routine, regardless of your age and sports interest.”
As individuals age they need more strength training. In Regaining the Power of Youth At Any Age, Cooper writes: “Up to age 50, people lose about four percent of their strength and muscle mass per decade. After that, the loss increases to about 10 percent per decade.” “By age 60”, he goes on to say, “the average man will have lost about one third of his muscle mass—unless he makes an effort to reverse the process through weight training.” Women have a similar decline as they age.
Cooper still leans toward aerobics because he believes the supporting evidence at this time is stronger. He cites a number of impressive studies showing that endurance training slows the steady erosion of oxygen uptake capacity with age that appears to occur for both trained and untrained individuals. He cites one study, which indicates that it may even be possible to stop the decline with hard consistent training. That study, reported in the Journal of Applied Physiology, followed a group of track athletes, age 50 to 82, who remained highly competitive for 10 years – and found that their aerobic capacity remained unchanged during the entire time.
Individuals who aren’t satisfied with a moderate level of fitness can take heart from a study published March 14, 2002, in the New England Journal of Medicine. The researchers concluded that exercise capacity is perhaps the most powerful predictor of mortality. They found a direct relationship between greater fitness and longer survival.
Most previous studies have emphasized that the least fit have the most to gain from exercise, that the most striking reduction in mortality results when one becomes active and moves out of the poor fitness category. An earlier study reported in 1989 by the Institute for Aerobic Fitness in Dallas highlighted that those in the high-fitness group were only slightly less likely to die than those in the medium-fitness groups, but this study shows that people benefit in proportion to their level of fitness.
As in other studies, the researchers found a "striking difference" in mortality rates between the least fit 25 percent and the next quintile of fitness. "This observation concurs with the consensus," the researchers wrote, "that the greatest health benefits are achieved by increasing physical activity among the least fit." They also demonstrated that there is a nearly linear reduction in risk with increasing quintiles of fitness. With each 1-MET increase in exercise capacity there was a 12 % improvement in survival. Participants whose exercise capacity was less than 5 MET were roughly twice as likely to die as those with exercise capacity of more than 8 Met.
Absolute exercise capacity measured in METs predicted risk of death better than percentage of age predictions. In both healthy participants and those with cardiovascular disease, peak exercise capacity was found to be a stronger predictor of death than risk factors such as hypertension, diabetes, obesity, heart arrhythmia, high cholesterol, and even smoking. Poor fitness proved to be the deadliest risk factor of all. Lead author Jonathan Myers, a professor of medicine at Stanford University, told the Washington Post "No matter how we twisted it, exercise came out on top."
Exercise pays big dividends. It’s even more important than smoking in its impact on life span. Greater fitness means longer life. What could be a bigger dividend than that? Doctors who don’t encourage their patients to exercise are missing the boat.
Gary J. Balady, M.D., summarized the message in an editorial which accompanied the report: "The data from the study compel the clinician to go beyond the identification of risk to the initiation of interventions, such as the prescription of increased physical activity and exercise, in order to modify risk, particularly in patients with low levels of fitness."
Benefits of Exercise Therapy for the Common Serious Diseases
Coronary artery disease7-11. Coronary artery disease (CAD) is our number one killer, responsible for 2,000 deaths in the United States each day. About twice as many heart attacks occur every day. CAD claims many people who are at the peak of their career.
Exercise combined with diet therapy can reverse established heart disease. Furthermore, exercise improves heart function, reduces several coronary risk factors (hypertension, high cholesterol, low high-density lipoprotein (HDL) cholesterol, and obesity), enhances psychosocial wellbeing after a heart attack, and improves survival.
In summary, exercise is an effective strategy for preventing heart disease, and it is a beneficial, low-cost, pleasure-giving treatment without the side effects of drugs or the risks, pain, and expense of surgery.
Cerebrovascular disease12-14. Vigorous exercise in early adulthood confers considerable protection from strokes in later life. This effect is independent of other risk factors. Furthermore, exercise is essential for restoring function following a stroke--again, a benefit not shared by drugs or surgery.
Hypertension15-19. Substantial evidence shows that exercise is an effective treatment for mild and moderate high blood pressure and is a useful adjunct for the treatment of severe hypertension. Many patients who adhere to a regular, specifically prescribed aerobic exercise program can reduce their blood pressure without taking drugs. Thus, they avoid the potentially toxic effects and considerable expense of long-term drug therapy. Drug and exercise compliance are reported to be similar. Postexercise blood pressure reduction in normal and hypertensive patients disappears 2 weeks after exercise stops.
The degree of blood pressure reduction depends on the type, duration, and intensity of the exercise, as well an individual's genetics. Therefore, the prescription must be carefully individualized. Among non-pharmacologic means for lowering blood pressure, physical activity provides better patient compliance and quicker results than weight reduction or alcohol and salt restriction.
Diabetes20-22. Exercise can prevent or delay the serious complications of diabetes, namely, the vascular disease of the brain, heart, kidney, eyes, and legs that commonly occurs in diabetics who are under age 40. The same benefits of exercise are seen in those who develop the disease in later life.
Exercise improves the abnormal blood lipid pattern and reduces the high blood pressure common in people who have diabetes. In addition, exercise increases insulin effectiveness and the metabolism of sugar, thereby reducing the insulin requirement, which in turn reduces the risk of vascular disease. Elevated blood insulin has been implicated in the pathogenesis of arteriosclerosis.
The complexity of diabetes treatment requires a combination of methods to achieve healthy blood sugar levels and to prevent or reduce the serious complications of the disease. An exercise regimen, properly taught and followed, helps accomplish this goal and allows diabetic patients to lead healthy, active lives.
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