The world is in the grip of an energy crisis.
The rising costs and dwindling supply of fossil fuels get all the press. but from a medical view, the real crisis involves human energy — or to be more specific, the lack of it. In the Philippines and many other countries in the world, it is an important contributor to four of the 10 leading causes of death: heart disease, cancer, stroke, and diabetes.
In all, sedentary living accounts for millions of premature deaths around the world annually. It is estimated that in developed countries, 10 percent of all deaths are caused by sloth, as are about 23 percent of chronic illnesses. It is a staggering burden of illness, death, and expense, and it’s all the more tragic because it’s unnecessary.
The Aerobics Revolution
The scientific study of exercise blossomed in the 1960s and ’70s. Its principal research tool was the maximum oxygen uptake test, which measures the amount of oxygen sucked up by the lungs, pumped by the heart, and delivered to the muscles during maximal exertion on a treadmill or stationary bicycle. Improvements in the maximum oxygen uptake, or VO2 max, quickly became the gold standard for judging the efficacy of exercise.
Research in many labs demonstrated that optimal improvement in VO2 max depends on vigorous exercise. The best results come from exercises intense enough to raise the heart rate to 70 percent to 85 percent its maximum, prolonged enough to sustain the intensity for 20 to 60 minutes, and frequent enough to occur three to seven times a week. The aerobics doctrine was born. Remember the mantra then? “No pain, no gain”!
In 1975, the American College of Sports Medicine issued its first exercise guidelines, calling for all healthy adults to exercise at aerobic intensity (60-90 percent of maximum) continuously for 20 to 30 minutes at least three times a week. These standards were soon adopted with only minor modification by the American Heart Association and the US Department of Health, Education, and Welfare, and they remained in effect for more than two decades. The aerobics doctrine inspired the few but discouraged the many. A relatively small number of lucky people discovered the benefits (and pleasures) of aerobic exercise. But based on the data at hand and with best intentions, doctors discouraged people who found aerobics too hard from getting moderate exercise by proclaiming that aerobic intensity was essential for benefit. For example, the Gospel of Aerobics preached that golf was the perfect way to ruin a four-mile walk, but we now know that’s wrong.
Fitness vs. Health
Epidemiological studies did confirm that fit people are healthy people, with reduced risks of coronary artery disease, hypertension, stroke, and diabetes, and a reduced mortality rate. These data remain valid: Aerobic training is excellent for fitness and health.
Without contradicting the value of aerobics, new studies show that it is possible to get nearly all the health benefits of exercise without reaching high levels of aerobic fitness. The answer is moderate exercise. In this formulation, intensity is less important than the net amount of exercise, and intermittent exercise is as effective as continuous activity. In fact, golf is very beneficial, indeed, as long as players walk the course and play two to three times a week.
The Benefits Of Moderate Exercise
For most people, aerobic exercise is daunting. Moderate exercise should be much more appealing and accessible, but the message has not yet sunk into the consciousness of most people. Part of the problem is the lingering belief that it’s a distant second best to aerobics — that walking is a pale imitation of running. When most people think of exercise, be they health care professionals or other folks, they envision a man or woman breathing heavily, sweating profusely, with tongue protruding out of the mouth. For the 100-meter dash, your coach was right — but for health, moderate, painless exercise is extraordinarily beneficial. Scientists have demonstrated the clear health benefits of exercise in animal experiments. Randomized clinical trials in humans prove that regular moderate exercises (such as walking), can produce a broad range of improvements in risk factors (cholesterol, blood sugar, body fat, blood pressure, etc.) that can be expected to improve health and reduce the risk of many diseases. Moreover, the large number of observational population studies done around the world suggests strongly that the biological plausibility of benefit is a clinical reality.
Although we don’t have the advantage of randomized clinical trials to evaluate the effects of exercise on cardiac events and mortality in healthy people, doctors have performed 48 such trials in patients with proven coronary artery disease. About half of the 8,940 patients were randomly assigned to receive the best medical and surgical care available; the others got the same standard of care plus enrollment in cardiac rehabilitation programs based on moderate exercise. The exercisers came out on top; in all, they enjoyed a 26 percent reduction in the risk of death from heart disease and a 20 percent reduction in the overall death rate. It’s powerful evidence that exercise protects the heart — and what’s good for ailing hearts should be at least as beneficial for healthy ones.
If cardiovascular risk reduction were the only benefit of moderate exercise, it would still be vitally important for every physically able individual. But it has many other benefits. Exercise is an essential partner with a healthy diet for people who need to lose weight. And many observational studies also suggest that “no sweat” exercises can help reduce the risk of stroke (by 21-34 percent), diabetes (16-50 percent), dementia (15-50 percent), fractures (40 percent), breast cancer (20-30 percent), and colon cancer (30-40 percent). If that’s not enough to get you moving, consider that exercise is also one of the two available ways to slow the physiological changes associated with aging; severe caloric restriction is the other. None of these benefits requires aerobic intensity exercises.
A 2005 analysis of data from the famed Framingham Heart Study reports that people who exercise regularly enjoy 3.7 years of additional life expectancy when compared with sedentary individuals. An intensity equivalent to walking at a pace of 17 minutes per mile was sufficient. And another 2005 study showed that moderate exercise (walking 8.6 miles a week at 40 to 55 percent of maximum heart rate) is enough to increase the VO2 max, though not to the same degree as aerobic training.
Physical activity vs. Exercise
One of the barriers to getting people moving is the academic distinction between exercise (formal structured activity to promote fitness) and physical activity (everything else). In our busy world, most people do not feel they can set aside time for formal exercise, especially intense workouts. In fact, the distinction is both arbitrary and misleading. Any physically active undertaking will contribute to health if it is part of an active lifestyle. Tending your plants in your garden and running the marathon are at opposite poles of a single spectrum of benefit. Activities at the low end of the spectrum require more time than those at the high end, but they are also safer and less likely to produce injuries — and the health benefits are remarkably similar.
There is also a need to encourage people to view physical activities as opportunities, not punishments. Climbing stairs instead of riding the elevator is one example of a healthful choice that incorporates exercise into the fabric of daily life. People should choose whatever activities work for them as long as they add up to enough exercise to maintain good health. As they experience the personal pleasures of moderate exercise, some will go on to aerobic training or to participate in sports.
People with medical problems or special needs require additional screening and supervision; in particular, everyone with known or suspected heart disease or major risk factors should have a thorough medical checkup and, in most cases, a stress test before starting an exercise program. Moderate exercise is the key to health but many people will get extra benefit by adding exercise for strength, flexibility, or balance — not necessarily at a gym under the watchful eye of a trainer, but at home in just a few minutes a day. And a prudent diet is an essential partner in the prevention of many chronic illnesses that plague our present society.
Medical science continues to make astounding advances. It has taken the collective effort of many dedicated scientists to bring us back to the wisdom of Hippocrates. Some 2,400 years ago, the father of Medicine said, “If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health.”