Can Exercise Extend Lifespan?
By John Abdo
I would like to begin this article by setting aside for a moment and instead using a bit of plain common sense. I'd like to discuss the relationship of exercise and longevity in a logical manner.
I've always felt that the healthier one is, the longer that person is likely to live. If one is weak and out of shape, and prone to pain, illness, and disease, it isn't likely that such a person will live very long, and if they did, they'd have a miserable life.
Most people who exercise on a regular basis report that they feel better perform better in both work and leisure activities, and enjoy life more than most people who do not exercise regularly. The vast majority of those who start exercising after living a sedentary lifestyle report marked health, performance and lifestyle benefits from engaging in regular exercise.
Lifespan Extension is Difficult To Prove In Humans
There have been studies showing that regular exercise over long periods of time reduces the risk of heart attacks, improves lung function, lowers blood glucose, cholesterol, and triglyceride levels, and improves muscle and bone strength with advancing age. These studies suggest that exercise can extend lifespan, but do not prove it, especially for the individual
It is exceedingly difficult to prove, or even to provide strong evidence in specific individuals for the common sense theory that exercise can extend lifespan. Lifespan extension is difficult to measure or predict in humans because we live so long and because we have yet to come up with a method to measure the rate of human aging over short periods of time.
We have no hard evidence, for example, that supplemental nutrients and drugs can extend lifespan in humans, although a number of these agents have extended lifespan in laboratory animals. We know that calorie restriction can extend both mean and maximum lifespan in rats and mice, but don't yet have such evidence in monkeys or humans.
The evidence for the effect of exercise on lifespan is stronger than for nutrient or drug supplementation because a few large-scale studies have been conducted comparing mortality in groups of individuals who have been physically active to similar groups of sedentary individuals. The results of these studies can be used to predict life expectancy in individuals whose exercise habits are similar to the subjects in the studies, but without any certainty that the findings apply to any particular individual.
Studies of How Exercise Affects Mortality in Humans
In general, the results of these studies show that regular, lifelong exercise reduces mortality and increases life expectancy in humans, but does not extend maximum lifespan, There are also studies showing that the initiation of regular exercise in sedentary individuals may increase their life expectancy at any age, but only if it is done in a gradual and prudent manner
In fact, there are studies indicating that extreme variations in exercise habits over one's lifespan, as well as the failure to exercise in a responsible manner may increase mortality and shorten life expectancy. More about that later. First, let's take a look at the studies of exercise and longevity in humans.
The Harvard Alumni Health Study
One of the most comprehensive studies to look at how exercise affects life expectancy is the Harvard Alumni Health Study, which was started in 1962 with 16,936 male Harvard alumni aged 35-to-74, under the direction of Stanford University epidemiologist R.S. Paffenbarger, Jr.. A series of reports on the findings of this study have been published in medical journals since 1986 when the New England Journal of Medicine carried a report entitled "Physical activity, all cause mortality, and longevity of college alumni".
In that report the scientists said they had obtained data over a 12-16-year period (1962-1978) about the extent and kind of exercise engaged by the Harvard alumni including activities such as walking, stair climbing, and sports such as swimming, tennis, basket ball, and golf. They found that 1,413 of the study subjects died during this period and that mortality rates (primarily from cardiovascular and respiratory causes) declined as physical activity increased, with mortality rates being "one quarter to one third lower among alumni expending 2,000 or more kcal during exercise per week than among less active men."
They concluded that "with or without consideration of hypertension, cigarette smoking, extremes or gains in body weight, or early parental death, alumni mortality rates were significantly lower among the physically active...By the age of 80, the amount of additional life attributable to adequate exercise, as compared with sedentariness, was one to more than two years."
In an update in 1994, the Stanford scientists reported a follow-up of 14,786 of the Harvard alumni aged 45-84 -- who had been originally surveyed by questionnaire in 1962 (or 1966) and again in 1977. They followed these Harvard alumni until 1988, or to age 90, a period in which 2,543 of them died. They found a major delay in mortality from all-causes and extended longevity in subjects who exercised regularly, did not smoke, and had normal blood pressure in contrast to sedentary men, men who smoked, and men who had elevated blood pressure.
In their most recent update, in JAMA (Apr 19,1995) there was another report on the data obtained from the Harvard alumni up to 1988 when the study was terminated. They compared men who had engaged in intense, vigorous activity over the years with those who had engaged in non-vigorous activity.
They concluded that:
The Framingham Study
A survey of the effects of exercise on mortality in 1,404 women, aged 50-to-74, in the famous Framingham study was reported in the American Heart Journal in Nov 1994. The scientists found that after 16 years of follow-up, 319 (23%) of the women had died, but that the mortality rate was lowest in women who had exercised most vigorously. They found that this increase in longevity was not due to reduced cardiovascular mortality.
Dutch Ice Skaters
In a 32-year follow up of 2,259 participants in the Dutch Eleven Cities Ice 8kating Tour, who were all athletes engaging in regular vigorous physical activity, were compared to members of the general population, who had a much lower activity level.
They found that the ice skaters lived IO%-to-25% longer than members of the general public.
Male Finnish World Class Athletes
In a study at the University of Helsinki, 2,613 men who had been either Finnish team members in the Olympic games, world or European championships or intercountry competitors during 1920-1965 in track-and-field, cross-country skiing, soccer, ice hockey, basketball, boxing, wrestling, weight lifting, and shooting were compared to 1,712 men selected from the Finnish Defense Forces.
They found that the world-class athletes who engaged in endurance sports (long distance running and cross-country skiing) and who had continued to exercise regularly throughout their lives, lived several years longer than athletes who had engaged in power sports (boxing, wrestling, weightlifting, etc.) or the control subjects. The increased mean life expectancy of these athletes was explained mainly by a decrease in mortality from cardiovascular diseases. No difference in maximum lifespan were noted in any of the groups.
Effects of Exercise on Longevity in Animals
In the 1960's, there was a study by Charles Goodrick of the Baltimore Gerontology Research Center in which exercise shortened the lifespan of laboratory mice. The reason for this negative finding was that the mice were forced to engage in heavy exercise (on an exercise wheel) in mid-life after exercising very little earlier in life. The stress of interrupting their leisurely existence and suddenly being subjected to heavy exercise is the reason the lifespan of the mice was shortened, not the exercise itself.
Numerous later studies, in which laboratory animals were allowed to exercise voluntarily, or conditioned on a lifelong basis, extended their lifespan. In recent years the effect of exercise on longevity in animals has been explored extensively by J.O. Holloszy of the Washington University School of Medicine in St Louis.
In one study, Holloszy showed that exercise in female rats, starting at 5 months of age, led to a "significant prolongation of average longevity without on increase in maximal life span"
The average age at death for the sedentary rats was approximately 924 days compared to 1009 days in the exercise rats. In this experiment, the exercised rats were fed more than the sedentary rats, but were similar in body weight because of their increased energy expenditure.
Exercise Slows Premature Aging And Prevents Diseases
Since exercise has not been shown to extend maximum lifespan in animals or humans it appears likely that exercise does not affect the underlying processes that cause us to grow old and die. However its ability to extend mean lifespan suggests that it is effective in slowing premature aging and in helping to prevent heart disease, arthritis, osteoporosis, and other diseases of aging.
Strengthening Bones and Muscles
Studies have shown that exercise strengthens bones and slows the progression of osteoporosis, a bone-thinning disease that commonly occurs in older women. Weight bearing exercise, especially from lifting weights and using resistance machines places a healthy stress on the bones and encourages new bone growth.
Additionally, with a well-conditioned muscular system, the body is kept in proper alignment. Since muscles hold the skeletal system in place, weak and out-of-shape muscles cause the body to be poorly aligned anatomically. Such malalignment can lead to degenerative joint disorders as bones and their connections, compress together. When joints become crowded, their natural gaps and lubrication is reduced, so that grinding during movement wears them down even further.
Extending Lifespan in Diabetics
Insulin-dependent ("juvenile") diabetics suffer from faulty pancreatic function, which keeps them from producing the insulin they need for carbohydrate metabolism. Such diabetics suffer a higher than normal rate of cardiovascular diseases and other pathologic complications that lower the quality of their lives and shorten their lifespan.
A study of the effects of exercise in 548 insulin-dependent diabetics at the University of Pittsburgh compared to non-diabetic controls between 1981 and 1988 showed that exercise level varied inversely with the occurrence of diabetic complications and mortality Sedentary male diabetics were three times more likely to die than physically active male diabetics. A similar but lower correlation was found in female diabetics.
The Risk of High Intensity Training
I believe many athletes may actually shorten their lifespans due to the high intensity with which they train. Intense training is a necessity in competitive sports but the frequency of training sessions, and the lack of recuperation time between sessions, is not adequate enough to repair damage from overly heavy training.
The athlete who constantly trains beyond his or her metabolic capabilities is subject to a variety of ailments including tissue damage hormone imbalance immune system dysfunction, and depression. Combined with the use of performance-enhancing drugs such as anabolic steroids and amphetamines many athletes are destroying their health in their quest for glory.
Studies have shown that athletes who to continue to exercise on a regular basis after their career is over often have lower life expectancy that members of the general public. ] A recent study in Japan looked at the longevity of 3,113 male graduates of a national university. The subjects were according to their academic majors, which physical education, the humanities and the sciences.
The results showed that the physical education majors died significantly sooner than the humanities and science majors. These findings suggest physical activity in youth is not necessarily correlated with and longevity.
Exercising For Health and Longevity
It is important to approach exercise as a regular activity designed to improve your health, rather than as a means to competitive success. Exercise must be part of a healthy lifestyle, including a good diet, nutrient and life extension drug supplementation, avoidance of smoking and excessive alcohol intake, reduction of environmental stress, and a positive attitude towards life.
Contrary to popular belief exercise does not have to be vigorous or difficult. As long as an extra demand is placed upon you above that which is normally experienced, your body will adapt to the new (good) stress and become conditioned, stronger and healthier. With this strategy year-round progress is assured as your activities are paced within your body's metabolic capabilities and recovery ability. Training for a marathon might not be your answer for health and longevity, especially if a 2 mile walk or run is your best prescription for health.
Learn how to Exercise
The necessity of learning the correct ways to exercise cannot be overemphasized. I encourage you to write down your goals, your strengths, and your weaknesses, and discuss them with a knowledgeable advisor or personal trainer, Start at your own pace and move forward when you feel capable. If you perform below your expectations on some days, don't be alarmed. your body has its own biorhythms and will fluctuate in energy and strength from one day to another Just get out there and enjoy yourself. You don't have to measure up to one else or to your previous performances.
Exercise sessions do not have to last several hours to be productive. If you exercise correctly, sessions well under an hour will be sufficient for all your needs. However if you like taking long walks or bike rides, or playing tennis, go ahead and enjoy yourself. To prepare and better endure your workouts, bring some water or maybe a good carbohydrate this will keep you hydrated and protect you form mineral imbalances
You Can Start At Any Age
Scientists have shown that exercise can be beneficial even if you start late in life, provided that you In a sensible manner. Remember you're never too old to start an exercise program. Start now! I don't care how old you are. Exercise isn't just for the young. It's for everyone!
Aging successfully relates to how well you have Iived our life. I've met many life extensionists who are searching for a "miracle" drug that will banish all the neglect of their previous year. White I believe there some great products out there that contribute to health and well-being, I feel that a foundation of good eating habits and sensible exercise must be laid if you truly plan to live life to its fullest and longest.
What I'm talking about is fitness for longevity.A science made simple once you tie the laces of your gym shoes grab that tennis racquet or lift that barbell. Whatever activities you select pursue them with joy and confidence that greater health and longevity will be the just rewards for your efforts.