Authors: Jörg Blech
Today’s brain researchers are correcting that devastating view. The body builds the mind as well as itself. If you exercise your muscles, you practically flood your gray cells with fresh nutrients and growth factors. These make new nerve cells grow. The new cells are easily stimulated and particularly capable of learning. But if we don’t make use of them, they die after a few weeks.
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“Exercise is the strongest known stimulus to grow new nerve cells,” says Henriette van Praag, an expert on neurogenesis at the Neuroplasticity and Behavior Unit of the National Institute on Aging in Baltimore.
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Once nerve cells are produced, mental activity is needed for these newcomers to survive. When used, the neurons are permanently integrated into the brain and able to increase its ability to learn.
That means we can train the brain just like a muscle, at any age. “Fitness training improves neuronal efficiency and performance,” says the psychologist Arthur Kramer at the University of Illinois in Urbana-Champaign. “Older brains are a lot more flexible and plastic than we have been led to believe.”
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No one has to work up much of a sweat to benefit from the healthy effects: People who exert themselves physically for half an hour three times a week, as researchers at Duke University discovered in a comparative study, protect themselves just as effectively against bad moods and attacks of depression as those who take mood enhancers every day.
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A study led by the University of Melbourne showed that walking for two and a half hours per week improves memory for older people and may stave off dementia.
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These encouraging findings are being made because doctors around the world are starting to study and measure the actual effects of physical exercise and evaluate its benefits. Many of these studies show that moderate training can be seen as a form of medicine in its own right, which can be confidently prescribed like a tried and tested drug. Medicine has reached a turning point, say researchers at the University of Copenhagen: The accumulated knowledge on the blessings of exercise “is now so extensive that it has to be implemented.”
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This paradigm shift to advising activity rather than rest involves the major diseases in particular. Osteoporosis, asthma, osteoarthritis, chronic back pain, and type 2 diabetes, for example, can all be improved and even overcome by exercise. In addition, hyperactive schoolchildren are being prescribed physical activity at playtime instead of pills. Tablets like Viagra can be replaced—by moderate exercise. A long-term study carried out on more than 500 men led researchers to conclude the only behavior that helps impotence patients is regular physical activity.
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Exercise also has a therapeutic effect on heart patients. If you raise the number of calories you burn, you reduce the probability of blockages in your coronary arteries. The cardiologist Rainer Hambrecht from the Bremen Heart Centre is studying this phenomenon at the level of single cells. “Patients with stable coronary heart disease,” he sums up his findings, “can increase their life expectancy by taking up a sport.”
Yet many doctors still recommend rest for various illnesses or even advise patients against any kind of physical activity. Especially for metabolic diseases such as diabetes and osteoarthritis, doing nothing can worsen the patients’ quality of life. The more researchers are finding out about these effects, the louder they’re calling for a change to the traditional advice for sick people to stay in bed.
“We are getting better, but there is still a long way to go,” says Robert Sallis, a family doctor in California and a past president of the American College of Sports Medicine. “Physicians increasingly acknowledge that exercise is good, but I do not think they are trained to think about it as a remedy. They much more quickly pull out their pad and write prescriptions for drugs, and they don’t have the training to help their patients to get more active.”
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Cancer patients in particular are still often advised against physical activity—because doctors believe that that helps them to cope better with the strenuous treatment. But it appears that the opposite is the case.
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Some physicians are now placing stationary bicycles next to the sickbeds of even seriously ill patients—and they find exercise cheers patients up and gives them back the energy they thought they had lost forever. Physical activity can strengthen the body’s own defenses against cancer—and even prolong the life of cancer patients.
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Strangely, these exciting findings have hardly made the rounds. The therapeutic value of sport in aftercare for cancer patients appears comparatively unknown and is often rather neglected. Melinda Irwin, a researcher at the Department of Epidemiology and Public Health at Yale School of Medicine in New Haven, says: “The leap has not been made that physicians recommend exercise for cancer patients.”
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Unfortunately, doctors’ advice for patients to rest is often likely to shorten many of the patients’ lives. Take heart failure, for example: The physiological processes that cause the problem of weak heart muscles are only made worse if the patient stops taking exercise, on their doctor’s advice. Well-informed physicians are now recommending the opposite: According to recent studies, sport can reduce the likelihood of dying from stable chronic heart failure by about 35 percent.
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KEEP MOVING TO LIVE LONGER
Researchers have also taken a new look at the effects of inactivity on healthy people. They have shown that office workers who make only minimal use of their muscles put themselves at almost as much risk as smokers. The mortality rate of inactive people is up to one-third higher than that of people who take regular exercise. A 65-year-old who walks less than one mile per day might die seven years earlier than a neighbor of the same age and the same risks otherwise who walks more than two miles per day.
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The rule is the same for everyone on the planet: If you engage in regular physical activity and push your muscles, you trigger adaptive processes that have a positive effect on your health. That doesn’t just go for sports that revolve around top performance, winning, and losing. It’s true for any way we bestir ourselves, including walking and such everyday activities as climbing stairs, cycling, weeding the garden, and cleaning the house. It’s this kind of healthy exercise that keeps us young and lengthens our lives, if we keep doing it in later life. The reward for burning an extra 500 to 2000 kilocalories a week is living longer; the mortality risk is 28 percent lower for 60- to 69-year-olds, and 37 percent for 70- to 84-year-olds.
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Evolutionary physiologists like Frank Booth from the University of Missouri in Columbia say it’s a fallacy to believe that physical inactivity does no further harm, as long as you keep a steady weight and eat sensibly. Modern human beings are still genetically programmed for life as hunters and gatherers because our genetic composition has hardly changed in the 10,000 years since the Stone Age. Back then, our ancestors were in top athletic form every day, looking for food, hunting wild animals, and building shelters. Those who weren’t able to keep up simply died out. Those who survived passed down the biological equipment needed under these conditions over the millennia. That means we all have perfectly functioning bodies—but only as long as we take exercise on a daily basis.
Presently, however, a large part of the world’s population makes a living in ways for which their genetic inheritance was never designed: Billions of people spend most of their lives sitting, at work and after.
We do of course live much longer lives than the cavemen, thanks to improved hygiene, obstetrics, and antibiotics. But “the average office worker would be much more healthy,” according to the American evolutionary biologists Randolph Nesse and George Williams, “if he or she spent the day digging clams or harvesting fruit in scattered tall trees.”
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Because the biochemical cycles get sluggish in inactive bodies, fats in the blood tend to form gallstones more often, for example. People who don’t take exercise have their gall bladders removed more often than the rest of the population. And because digestion slows down in bodies that don’t move much, the period of contact with carcinogenic substances in our food is lengthened; inactive people have a 50 percent higher risk of contracting bowel cancer. Even the genes became affected because being lazy appears to make us genetically old before our time. Researchers in Newark, New Jersey, and London found that pieces of DNA called telomeres shorten faster in physically inactive people, making them prone to quicker cellular aging.
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Frank Booth puts most diseases of modern life down to the fact that our metabolisms are going off course because of chronic lack of activity. He and other scientists recommend a minimum of 30 minutes of moderate exercise a day—walking or swimming, for example. Everything below that is defined as inactive. “Without that threshold of physical activity expected by our genomes,” says Booth, “physiological dysfunction is likely to occur from pathological gene expression, eventually leading to chronic health conditions.”
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If this sounds gradual, and not that threatening, put it this way: The body of anyone who doesn’t take at least half an hour of exercise every day is in a state of emergency. Pathological processes are constantly taking place in the cells and tissues, and it’s only a matter of time until irritations and complaints break out.
According to the evolutionary biologists, we have to rethink the old view of exercise: movement is by no means just a useful added way to improve our health. In fact, it is absolutely necessary for the human body to work normally. That goes for all ages: Children can develop their mental abilities properly only if they do enough running, jumping, and physical playing as well. Motor and cognitive skills develop in unison and stimulate each other within the brain. Researchers in the field of neuroanatomy at the University of Bielefeld sum up what that means for parents, children, and teachers: “Learning needs movement.”
The new findings suddenly put what we think of the aging process in a different light: many of the changes are to a great extent the result of inactivity.
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We spend vast amounts of money on the products of the antiaging industry, but so far all the pills, hormones, live cell injections, vitamin cures, and orthomolecular procedures have been an abject failure. But don’t despair: A fountain of youth is at hand—but it just takes a little effort. Only regular physical activity can slow up the biological aging process. In other words, being active is the only way not to look old.
We don’t age chronologically but biologically. If we keep our bodily functions vital, we can slow down or stop the biological aging process—over decades. That’s practically a law of nature, and you and I can make it work for us.
Of course, physical exercise can never guarantee that an individual won’t get sick. The author James Fixx remodeled long-distance running as “jogging” and popularized it around the world—only to collapse and die at the age of 52 while out on a jog on a lonely country road. However, atherosclerosis was running in his family, and he might have died earlier without picking up the habit of exercising.
No one is claiming we can literally run away from sickness. The Norwegian Grete Waitz won the New York City Marathon nine times and has recently been battling cancer. The cyclist Lance Armstrong contracted testicular cancer after becoming the world road race champion. These stories illustrate that fate and bad luck also play a role in disease, especially tumors.
We all know the feeling: whenever we come down with an illness, we always look for explanations, for reasons why it got so far. But doctors have long since found evidence that the course of health disorders is influenced by not only genetic and environmental factors, but also by pure coincidence.
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By the time Lance Armstrong was diagnosed with cancer, he had metastases in the whole of his body and brain. The doctors estimated his chance of survival at below 50 percent. Armstrong himself puts the fact that he was still healed and made a spectacular recovery down to “a lucky coincidence.”
But at the same time, the likelihood of many healthy decades of life can be improved by living an active lifestyle. Epidemiological studies indicate one factor again and again: Daily physical activity is linked with a lower risk of cardiovascular diseases, strokes, loss of memory, depression, type 2 diabetes, obesity—and with a longer life. It also reduces the risk of breast and bowel cancer. There is no doubt: If we could put the positive effects of moderate exercise in a bottle, we’d all take a good swig from it every morning. Canadian doctors reported that the elixir is even stronger and more effective than previously assumed. “Recent investigations have revealed even greater reductions in the risk of death from any cause and from cardiovascular disease. For example, being fit or active was associated with a greater than 50 percent reduction in risk.”
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Ninety percent of over-50s would benefit from regular training—and the good news is, it works just as well if we take it slowly. It doesn’t always have to be jogging—even brisk walking has proven effective.