Healing Through Exercise Part 4

Another support for the cancer-preventing effects of exercise can be found in studies of diabetes. Insulin produced in the pancreas is needed by cells so that they can absorb glucose from the blood and store it. The level of insulin must correspond to the bodyas needs, and if this balance is destroyed, the likelihood for developing cancer increases.

Patients suffering from type 2 diabetes have been found to produce higher quant.i.ties of a protein called insulin-like growth factor I (IGF-I), which is thought to trigger cancerous growth. The rates of colon, liver, pancreas, endometrium, and breast cancer are in fact higher among people with type 2 diabetes. 12 That does not sound good at all, but luckily one can do something about it: Physical exercise, as we saw, can reverse the symptoms of diabetes and also appears to lower the IGF-I level.

BMI AND CANCER.

As they continue to explore the causes of cancer, doctors ascribe a greater role to obesity than they once did. British scientists reviewing data pooled from more than 140 studies have just confirmed that the risk of developing a number of common and some less common cancers goes up with increasing BMI.13 An earlier study had already revealed that the risk of obese men for developing an extraordinarily aggressive version of prostate cancer is increased by 80 percent.14 Thomas Hawighorst and Gnter Emons, at the University Hospital Gttingen, Germany, published a review article on the subject painting a very somber but realistic picture. By now, there is asufficiently hard evidence for the connection between adiposity and an elevated risk for cancera of the endometrium, the kidney, the breast, the colon, and esophagus, whereas, aThe prognosis for adipose women with breast cancer is worse, and gaining weight after the diagnosis also has a bad prognostic effect.a15 The American Cancer Society published a particularly extensive survey on the subject.16 The study started more than 20 years ago and included more than 900,000 women and men. Their average age was 57, and none had any tumor-based diseases. In the following 16 years, 6.3 percent of them died because of a condition that was caused by cancer. Then, the researchers a.n.a.lyzed the data to see whether there was a link between the death rate and body weight. In order not to distort their findings, they excluded risk factors and used only data from people who never had smoked.

According to the study, the risk for dying from cancer is approximately 10 percent higher for women with a BMI between 25 and 29.9 and three times higher for women with a BMI between 30 to 40. And extremely obese women have a risk for dying from cancer that is elevated by 88 percent, compared to normal-weight women. The data of the men revealed a similarly gloomy picture.

In total, the researchers figure that obesity causes about 20 percent of all deaths of women related to cancer. Among men, the number is about 14 percent. The experts of the International Agency for Research on Cancer in Lyon, France, estimate that 25 percent of cancer cases worldwide are caused by excess weight or obesity and a sedentary lifestyle.17 Apart from overeating, lack of exercise is in most cases the reason why people balloon and develop a pathological condition. Excess fat on the body impairs the whole metabolism and causes several of the risks mentioned earlier. The biochemistry of the estrogens becomes messed up, and the insulin system gets out of balance. The longer an affected person remains physically inactive, the worse everything getsa"because muscle ma.s.s is incrementally replaced with fat.

Love handles and potbellies are by no means pa.s.sive additions to a body; rather, they actively interfere with some processes in the rest of the organism. Certain messenger substances, so called adipocytokines, are produced by fat tissue and can play a role in the development of cancer. The experts Hawighorst and Emons conclude that in obese people athe metabolic-biochemical effects of overweight can cause the formation of a malignant tumor in a multi-level process.a18 Researchers still speculate whether and if exercise affects an already existing tumor. Physical activity increases the demand for oxygen and nutrientsa"which might starve the tumor of these resources. If the blood is primarily pumped into the muscles, one could reason that there is not much left to feed the tumor.

Although evidence continues to acc.u.mulate that being physically active reduces a personas risk for developing certain cancers, to date, the many details of the mechanism remain unknown. Many factors may act together and might vary from individual to individual. However, even though the ideal amount of exercise to prevent cancer has yet to be determined, doctors and physiologists working in the field are convinced that becoming active is worthwhile anyhow. As Kim Westerlind of the AMC Cancer Research Center in Denver, Colorado, concludes, aIt would appear reasonable to suggest that regular moderate physical activity be incorporated into [a] healthy lifestyle for all its already well-established benefits, as well as to potentially reduce cancer risk.a19 EXERCISE AND QUALITY OF LIFE IN CANCER PATIENTS.

The doctrines of few medical fields have been as drastically turned around as they have in cancer medicine. Generations of doctors had been taught that people diagnosed with cancer primarily needed rest. Patients were discouraged from exercising, out of the erroneous belief that this would worsen their health. When the physician Klaus Schle established the worldas first training group for cancer patients in Cologne, Germany, many of his colleagues were outraged. A radiologist warned him: aCan you guarantee you are not going to trigger metastases?a Schle replied: aCan you guarantee that your rays donat trigger growth of new tumors?a20 By rejecting exercise for their cancer patients, medical doctors did more harm than good, says Fernando Dimeo of the Hospital Charit in Berlin. aDuring chemotherapy and the weeks and months to follow patients were put in a pa.s.sive role. Doctors were afraid of overburdening them and advised many of the patients not to partic.i.p.ate in sports and demanding activity even in the long term.a21 But recommending cancer patients to take it easy has severe consequences. At first, people are shocked to learn they have cancer. Then, they are told not to use their bodies much any longera"which makes the situation even more devastating because they now feel completely at the mercy of their illness. On top of this, being confined to rest worsens the impact of chemotherapy and of the cancer drugs, which can cause anemia and heart problems and loss of strength as well as vitality. As a result they are tired, and they become short of breath. aThese symptoms can be worsened by lack of exercise and the subsequent loss of endurance,a warns Dimeo.

In no time the patient is caught in a vicious circle of declining activity and decreasing resilience. Recovery is slowed after each stage of cancer treatment, thereby causing even more inactivity. After a while, a patient enters a phase regarded as a disease in its own right, the so-called fatigue syndrome. Once the cancer treatment is completed, this condition is the biggest problem many patients facea"and can be a direct consequence of medically prescribed lack of exercise.

Too much rest can also worsen the primary disease. As we saw, women diagnosed with cancer have a worse prognosis when they put on five kilograms or more during their cancer treatments. Intriguingly, many patients themselves have intuitively sensed that rest was not good at all for thema"and decided to do something about it. In the United States many people diagnosed with cancer began exercising hard because they hoped this might improve their quality of life and survival chances. One of the pioneers of this movement is Anna Schwartz. When she fell sick with non-Hodgkinas lymphoma, she reminded herself of what had often struck her when she worked as a nurse in an oncology clinic. Those patients who, despite the exhausting treatment, regularly left their rooms and stayed physically active awere in a better mood,a Schwartz recalls. And when she had to go through chemotherapy, she forced herself to exercise. She went jogging and played tennisa"despite a catheter for the cancer drugs in her body.

Since then, this thoroughly fit woman, who is considered as good as cured, has turned her story into a job. Research grants from the National Inst.i.tutes of Health enabled her to carry out scientific studies on the subject. In the resulting publications Schwartz has shown that exercise indeed ameliorates the fatigue syndrome and makes patients stronger again.22 Since then, Schwartz has been offering horse riding for cancer patients in Cave Creek, Arizona, has been giving talks, and has written a book about fitness and cancer.23 The preface was penned by Lance Armstrong who, after overcoming testicular cancer, won the Tour de France seven times. Armstrong himself has declared that he was better and stronger after his illness than before. aWhen people are diagnosed, their first impression is aOh my G.o.d, I am going to die,aa he once said. aOver time, they lose that impression. They get the confidence back, they know they are going to live, they get back to life, they get back to work and they get back to exercise.a24 Encouraged by Armstrongas incredible story, cancer patients began improving their odds and their lives by exercisinga"although many oncologists still dismissed sports, thinking its strain and stress would only weaken patientsa immune systems. By now, however, this patientsa movement has led to a change of thinking among many doctors, says Julia Rowland of the National Cancer Inst.i.tute in Bethesda, Maryland. Many new studies have been initiated to reveal the impact of exercise on cancer patients.

The results, says Rowland, have shown that the oncologistsa worries have been unfounded. In many cases exercise actually does improve the mood of the patients and their strength, while lowering the side effects of radiation and chemotherapy.25 When breast cancer patients try strength training two days per week, both physical and mental strength improve significantly.26 Yet exercise does not need to be a daunting activity or even an organized outing to produce significant rewards for breast cancer survivors, researchers at the University of Texas M. D. Anderson Cancer Center, in Houston, have found. Over the course of six months, they regularly met with women who had gone through breast cancer treatment and led sedentary lives. At the meetings the women were encouraged to integrate physical activities like brisk walking and climbing stairs into their lives, five days per week, at least 30 minutes at a time.

After six months, the mobilized women showed many improvements. In contrast with inactive patients, they felt much healthier and had less pain and fewer handicaps. Their const.i.tutions were substantially strengthened, which was doc.u.mented by a small compet.i.tion at the end of the study: the active women were able to walk faster than the inactive ones. aThe wonderful take-away message from this study is that simple exercises, such as walking during coffee breaks or parking farther away from work, can have beneficial effects on physical health and functioning,a says the studyas princ.i.p.al investigator, Karen Basen-Engquist.27 By now, some doctors prescribe exercise even when chemotherapy is still under way or right afterward. Most patients, it is true, do not feel like working out at all. Chemotherapy and radiation therapy not only destroy cancer cells, but also kill stem cells, which give rise, among other things, to cells of the immune system. Thus, immediately after treatment patients have few bodily defenses and are isolated in separate rooms to protect them from potentially deadly viruses and bacteria.

However, this well-intentioned isolation comes with a price, says the sports physician Klaus Schle. In his pioneering work, he has found that bed rest significantly lowered the physical resilience of these individuals. The more rounds of cancer treatment they receive, the harder it is for them to recover. To change that, Schle and three colleagues did something unheard of: they placed stationary bikes in the rooms of 32 patients and encouraged them to pedal for 10 to 20 minutes once or twice a day. Unlike 32 patients that had been isolated the old, sedentary way, these exercising patients recovered faster and more thoroughly from the side effects of cancer treatment. Even very sick patients actually do profit from exercise. They gain muscle strength and endurance without worsening the primary disease.28 EXERCISE AND SURVIVAL.

Even the most optimistic physicians never seriously expected that physical exercise might prolong the life of cancer patients.

But in recent years data have started to emerge indicating that exercise indeed improves survival rates. The effects seen so far are modest in absolute numbers but relate to two of the most widespread and dangerous cancers. Two of the trials involve patients with colon cancer. One included 823 patients with early-stage or slightly advanced tumors that had surgery and adjuvant chemotherapy.29 Six months after the completion of the therapy, Jeffrey Meyerhardt at Dana-Farber Cancer Inst.i.tute in Boston asked them to report how much physical activity they had engaged in. The data show that exercise corresponding to walking for 60 minutes, six days per week aappears to reduce the risk of cancer recurrence and mortality.a Meyerhardt has produced similar results in another study in which he and his colleagues observed 573 women who had been treated for colon cancer.30 Patients who started exercising after their diagnosis lived longer than sedentary ones; the survival rate was increased by 50 percent. Since that study, Jeffrey Meyerhardt tells his patients that aexercise might be advantageous for them.a Finally, the epidemiologist Mich.e.l.le Holmes of Brigham & Womenas Hospital in Boston has found a similar effect for breast cancer.31 She and her colleagues a.n.a.lyzed the cancer progressions of nearly 3,000 women and found a significant correlation between the level of activity and survival. If a woman walks three to four hours per week, the risk of breast cancer death is lowered by 50 percent.

When an effect in a similar range is seen using a conventional cancer drug, leading doctors are quick to talk about a amajor advancea or a amajor turning point.a32 Meyerhardt and Holmes are much more cautious and say that their findings are not proof at this point. A correlation between cancer survival and exercise level does not prove that exercise was the cause. There is no study yet that would say a person can literally run away from cancer. However, more and more data point to the benefits of physical activity.

Now, many oncologists are eager to explore the cancer-fighting properties of exercise further and to carry out more studies. Which kind of exercise would be the best? What would be the ideal amount? However, will the drug industry fund such research? aThere is no doubt that the pharmaceutical industry would back an agent with potential to reduce cancer recurrence by at least 50 percent,a says Wendy Demark-Wahnefried of Duke University Medical Center in North Carolina. aBut who will back a trial that evaluates the potential benefit of sneakers and sweatpants?a33

13.

Longevity, Potency, and Resilience.

AT AGE 20 THE IDEA OF GROWING OLD IS SOMETHING TO THINK about later in life. The body is still going strong; injuries and wounds and broken bones heal rapidly, and there is no moaning and groaning to be heard first thing in the morning. At age 40 wrinkles and the first aging marks appear and love handles may have established themselves in the midsection, but there is still no time to think about getting old. At age 60, people may have gone through one or two operations, perhaps after an unfortunate fall while on vacation. Among friends and acquaintances, the first deaths occur. Subtly one starts to get accustomed to the fact that the body may not be in the best shape. Hearts may start to beat out of rhythm, legs may be swollen in the evening, sleep is no longer so predictable.

This scenario is true for many peoplea"but not for everyone. Around us are people who hardly seem to age, who look nearly the same in the course of many years. In the science department of my magazine there is a slim female colleague who, in the ten years Iave known her, has never really changed. People guess that her age is about 48, but she is 61. Not long ago, such a woman would have been marveled at. In 1900, life expectancy at birth in the United States was 47 years,1 but now it is 78 years at birth for the total population in the United States.2 This increase in life span is remarkablea"and unevenly distributed among the people. One person struggles with bad health and dies at age 60, while another lives to be 100. Why is it that some peopleas bodies break down, while others remain radiant with health?

When you pose this question to people who are blessed with long and healthy lives, itas striking to see how frequently they mention physical activity. On a campground in Sequoia National Park, in the Sierra Nevada Mountains in California, I met an 83-year-old man, Alan Buckley, and asked him about his secret as we held sticks with marshmallows into the fire. Even though many men of his age live in old peopleas homes, Buckley camps every summer in the mountains and looks in the evenings at the Milky Way before going to bed. So what is his secret? Buckley says he simply always walks when he moves around on his walnut tree plantation. He shakes his head when he thinks about the aweekend warriors,a as he calls them, who sit in their cars and offices and armchairs during the week and try to make up for the missed exercise on the weekend.

Antonio Pierro also was always in motion. He was born in 1896 in Forenza, Italy, and sailed at a young age on a s.h.i.+p of immigrants from Naples to New York. He fought as a soldier for the United States in the First World War and then settled in New England. During his entire life, he was active, raking leaves and shoveling snow until he died at age 110. Antonio Pierro also said exercise was his secret. He once told a reporter: aIf you donat have exercise, you get stiff, youare not worth anything.a3 There are many such examples. In our family, it was grandfather August. He lived in the country outside Cologne, Germany, and worked as a carpenter at a time when craftsmen took a nap in the hay after lunch. Every day, August took an evening stroll for an hour, and he lived to be 98 years old.

These long and fulfilled lives are more than just chance. Epidemiological studies of thousands of men and women have shown that the regular use of our muscles is the only means capable of prolonging the human life.4 Being fit reduces mortality by 50 percent. People who burn 1000 kilocalories per week by additional exercise increase their probability of surviving by 20 percent. And if people become physically active but also quit smoking, they will live eight years longer, on average.

After all, we are born to run. We evolved the ability to run long distancesa"and this, believes the anthropologist Daniel Lieberman at Harvard University, was crucial for our evolution. When it comes to endurance, we are among the best athletes in the animal kingdom. Leopards, for example, might sprint much faster, but over long distances, the big cats will be worn out before long. Actually, most mammals are not capable of running or trotting for longer than 15 minutes. Chimpanzees, with their bowlegs, come off especially badly. In contrast, humans evolved to become true endurance runners. Thanks to our uncovered skin and our sweat glands, we are able to regulate our body temperature even when we move for an extended time in hot weather. And unlike all the other apes, the human body sports a large gluteal muscle, Musculus gluteus maximus, which in biomechanical terms enables us to run. Because our potential for endurance running is genetically hardwired into our bodies, we can utilize it even in old age. aHumans are astonis.h.i.+ng athletes,a Lieberman says. aThey can keep running.a And yet physicians traditionally thought older people would not have these capabilities. When older runners started attempting marathons, doctors and organizers wondered whether they would need additional care. But these runners did just fine: older athletes can reach the finish line just as comfortably as the younger ones. It is not age that matters but preparation and fitness.5 Bob Matteson of Bennington, Vermont, began his running career at age 69. By now this ancient gazelle is in his 90s and belongs to the fastest people of his age group.6 The course of our lives is often set in middle age. Good strength of grip and normal weight are predictors for an unusually long life. Conversely, the risk of dying because of cancer increases by 29 percent among sedentary women. If a person does not exercise at all, basic strength decreases every year by 1 to 2 percent. At some point, strength falls short of a certain threshold, leaving the muscles unable to fulfill their functiona"until finally one day a person is too weak to get up from a chair. Comparing this loss of 1 or 2 percent of strength per year with the gain of 30 to 40 percent that can be achieved by training makes it clear that the potential for renewal amounts to 15 to 20 years, which beats any antiaging remedy by far.

Any person who was born healthy can reap the good effects of exercise. Contrary to common belief, this is little affected by an individualas genetic makeup. The impact of the genes on the life expectancy is much smaller than most people would imagine. A survey among thousands of twins revealed that the physically active member of the pair has a significantly lower mortality than the sedentary sibling.7 The proverb that one should choose oneas parents carefully in order to have a long, healthy life is becoming less true. Genes may determine the way we age by 30 percent;8 the environment determines the rest. To a large extent, we determine how fast we age. Apart from smoking, it is above all disuse of the body that shortens lives. This weakens the potency of men, makes us vulnerable to stress, steals our healthy sleep, and increases the number of illnesses we get.

WORKING OUT FOR POTENCY.

It was the first day of June 1889 when the neurologist Charles Edouard Brown-Sequard declared at the Biological Society of France in Paris that he had discovered a fountain of youth and had already tested it. The result, the 72-year-old professor claimed, was nothing but a sensation. Brown-Sequard said he felt physically strong and mentally awakened. He had gotten rid of his constipation and urinated again like in his young days, in a high arch. The professor was convinced these improvements were due to an extract he had prepared from the testes of guinea pigs and dogs, and subsequently injected into his own body. As it turned out, this supposed antiaging regimen had, if anything, a placebo effect because its recipe was simply too weak to work. Nevertheless, Brown-Sequard had founded a new field dealing with the production and effects of hormones, today known as endocrinology. Furthermore, his hunch that the testes are an important reloading point for hormones was subsequently proven right.9 By 1935, chemists were able to simulate the work of the glands by synthesizing testosterone in the laboratory. Normally, it is produced in the male body but alsoa"in smaller amountsa"in the female body. It promotes the maturation of the male reproductive organs; helps with the production of new sperm; and, in both s.e.xes, strengthens the libido.

Furthermore, testosterone acts as an anabolic hormone and increases the buildup of proteins in cells, enabling muscle growth, for example. Small wonder that testosterone and the similar hormone DHEA are marketed as antiaging products and consumed by many men. Doctors and public-relations people with ties to pharmaceutical companies even invented a disease, which they have named amale menopause,a to generate more sales. Due to an age-related decline of testosterone, men supposedly become sluggish, s.e.xually slack, and grumpy.

But in reality, hormone prescriptions help only the drug manufacturer and the prescribing doctor. A study has just shown that neither testosterone nor DHEA enhance well-being when given as drugs. A two-year study of elderly men (using testosterone plaster and DHEA tablets) and women (taking DHEA tablets alone) tested these products. Although this resulted in higher hormone levels, it did not affect muscle strength, aerobic capacity, or quality of life. There was no trace of an antiaging effect.10 Obviously these hormones are helpful and effective only if produced by the body. This natural buildup is stimulated by exercise. This has been shown time and again by researchers like John McKinlay and his colleagues of the New England Research Inst.i.tutes in Watertown, Ma.s.sachusetts. In the 1980s they randomly contacted more than 1,700 men between 40 and 70 years of age. Over time, the researchers a.s.sessed the health of those men via questionnaires and by measuring their hormone levels. On the one hand, the researchers found that the level of male s.e.x hormones incrementally decreases over the course of time; the testosterone level goes down by about 1 percent every year. On the other hand, testosterone level is significantly influenced by lifestyle. Heavy smokers and people who drink a lot of alcohol have lower hormone levels. Inactive, obese men also have a level 10 to 15 percent below that of physically active men of the same age.11 Men suffering from hot flashes often turned out to be sedentary heavyweights. The impact of obesity and other adverse lifestyle factors is roughly as big as the impact of natural aging.12 Thus, McKinlay concludes that male menopause is nothing but a myth, the symptoms more likely to be caused by laziness and an unhealthy lifestyle.

So if men want to boost their testosterone, they simply have to become active. Several studies examined what happened when men at age of 70 began to work out. Unsurprisingly, their strength increased. But their levels of testosterone and growth hormone rose, too. Whereas the hormone production of fit men responds especially strongly to stimuli, formerly inactive men profit, too. Sedentary men aged 66 to 76 training just for one hour on a stationary bike have seen their level of testosterone go up by 23 percent.13 Physical activity also helps men suffering from impotence. The condition, also called erectile dysfunction, is seldom the only problem of the affected men. An individual with an erectile dysfunction usually has quite a few other health issues, such as coronary heart disease, impaired circulation of the legs, and strokesa"all of which are caused by a lack of physical exercise.

So, is a flaccid p.e.n.i.s an indicator for lack of exercise?

Many findings point that way. An elevated body weight is connected with potency problems. The link between impotence and lack of exercise appears to be the endothelium of the blood vessels, which, as we have already seen, is impaired by inactivity. When that happens, the p.e.n.i.s is not properly supplied with blood any longer.

Common sense as well as scientific data thus tell us that impotent men need workouts rather than v.i.a.g.r.a. Whereas the pills are expensive and have side effects, physical exercise is safe and free.

In the Ma.s.sachusetts Male Aging Study, John McKinlay and his colleagues followed more than 590 men.14 At the start of the study, they were middle-aged and all potent. Eight years later, only 83 percent of them had satisfactory erections and, apart from alcohol abuse and smoking, obesity and lack of exercise were the main reasons for the problem. By contrast, some previously sedentary men in the study had adopted an active lifestyle. In comparison to inactive partic.i.p.ants, their likelihood of impotence was reduced by 70 percent. aEarly adoption of healthy lifestyles may be the best approach to reducing the burden of erectile dysfunction on the health and the well-being of older men,a the doctors conclude. Their recommendation? A brisk two-mile walk every day keeps erectile dysfunction away.15 The physician Katherine Esposito has used this effect to help men from southern Italy.16 The 110 partic.i.p.ants in her study were all impotent and overweight (BMI of 30 to 49).

They were randomly a.s.signed into two groups. The control group received information about improving their diets and exercise, but it was kept rather unspecific. Over the next two years they were visited bimonthly by the researchers, but no specific individualized program was provided. The men of the intervention group, however, were asked to lose 10 percent of their body weight and were given concrete tips, namely that they should not eat more than 1,700 kilocalories per day and should begin an active life with swimming, ball games, and many walks. Every four to eight weeks, these partic.i.p.ants were counseled by nutrition experts and physical educators.

Two years later, Esposito compared the two groups. Although there was no difference between the groups with regard to their eating habits, their activity patterns differed profoundly. Among the men only vaguely instructed about physical activity, the amount of exercise went up from 51 to 84 minutes per week. In the other group, however, the increase was from 48 to 195 minutes per week. The program also affected body weight. Whereas the BMI went down from 36.4 to 35.7 in the first group, the men in the training group lost much more fat; the average BMI declined from 36.9 to 31.2.

This lifestyle change was very beneficial for s.e.xual performance. Whereas 5 percent of the men in the control group were able to overcome their impotence, 31 percent of the exercisers were able to do so. This result fits the data from epidemiological studies, which indicate that 79 out of 100 men with erectile dysfunction are overweight or obese.

Many men do actually intuit the potential exercise has for their potency. That was revealed when the Ma.s.sachusetts Male Aging Study examined the course of erectile dysfunction.

More than 300 men were followed for nine years, and during this time impotence problems worsened among 33 percent of them. But in 35 percent of the cases the condition had disappeared. These latter men had apparently adopted healthier lifestyles, with less overeating and more sports, and thus had reversed their illness.

The study has two important messages. First, natural aging impairs potency to a much lesser degree than thought. Second, men can overcome penile problems without pills. This is probably not only because of the physiological improvements, which lead to a better blood supply to the erectile tissue. It might also be that exercise helps men to deal better with stress. With less psychological pressure, l.u.s.t and libido certainly profit. In a true win-win situation, frequent s.e.x enhances fitness and activates the production of hormonesa"which in turn creates even more desire.

STRIKING BACK AT STRESS.

The reason why exercise keeps bodies young and fit is not as evident as it might appear. After all, even moderate use of the muscles leads to an elevated consumption of oxygena"and thereby to an adverse side effect called oxidative stress. In the wake of this stress, highly reactive chemicals are produced, called free radicals, which can damage a cellas DNA.

Fortunately, we are able to protect ourselves against these dangers. As soon as the body is put in motion, a special program is switched on that can neutralize the adverse effects of exercise as well as psychological stress. The gerontologist Suresh Rattan of University Aarhus in Denmark believes that this protection is created by certain proteins (which, for historical reasons, have the confusing name of aheat shock proteinsa). They act as a s.h.i.+eld against stress and thus enhance well-being. In the bodies of Stone Age people, this program was probably switched on most of the time. All humans living today have the same system hardwired into their bodies, but it is usually switched off because modern people hardly use their muscles.17 The problem is, when this stress s.h.i.+eld is turned off, people are still subjected to stress, of a kind that might be even worse than the stress our Stone Age forebears usually had to deal with. Back then, stress always meant that there was an immediate threat and life was in danger. Those situations involve a swift bodily response: energy is released, and the muscles are supplied with glucose. The heart starts beating faster, and blood pressure and breathing frequency increase so that the body can consume more oxygen. Functions that are not needed in life-threatening situations are suppressed: the s.e.x drive, digestion, and the immune system. At the same time, the body is flooded with stress hormones. They ensure that we do not feel pain and sharpen our senses. This system stood the test when our forebears were escaping from mammoths and saber-tooth tigers, and it helps us to this daya"for example, should we have to flee a burning house or run away from other dangers.

So far, so good. But there is a problem: today, even when it is not a matter of life and death, stress waves keep rolling in, due especially to the acceleration of daily life that does not allow us to take any rest periods. Many employees can be reached day and night because of cellular phones, e-mail, and text messages. American companies in particular a.s.sume they can disturb their employees at any time, even vacations. There has never before been more continuous stress than in the technologically connected job world. Absolute silence and peace, on the other hand, can also be bad. Individuals who have no friends and must live in social isolation are often burdened by stress, too.

In past times, stress lasted only a short while: Either the saber-tooth tiger got you, or not. Nowadays, stress persists the whole day. Furthermore, stress and the corresponding response are uncoupled in sedentary people. The released energy is not converted into action but stays inside the body. Rather than actively defending against threats, the author Tara Parker-Pope concludes: aNow youare just a person with unregulated blood sugar, high blood pressure, blood clots, a depressed s.e.x drive and a buckling immune system.a18 Add to that the effects on the brain. An excess of stress hormones (glucocorticoides from the adrenal gland) impairs nerve cells and causes atrophy in certain brain regions.

The many consequences of stress for the physiology can be measured and expressed in a unit called aallostatic load.a Poor, badly educated individuals usually suffer more stress than people who are affluent and have had extensive education. Sleep deprivation and physical inactivity are also a.s.sociated with an above-average allostatic load.

However, n.o.body is at the mercy of stress. We can take measures either to minimize it or prevent its more dangerous effects. A social network seems to help against it. People who have an intact family life, are on good terms with their relatives, and have friends are found to have comparatively lower levels of stress hormones in the blood and live longer than the average.

If stress cannot be circ.u.mvented or evaded, which is unfortunately often the case, physical activity is the best answer to it. Rodents running on treadmills do not develop brain disorders as quickly as sedentary rodents when put under stress. They appear to be protected by a still poorly understood mechanism against the adverse processes stress can trigger in the brain.19 From the vantage point of evolution, this makes perfect sense: aa.s.suming that the stress response is a neuro-endocrine mechanism that occurs in antic.i.p.ation of physical action, then physical activity should be the natural means to prevent the consequences of stress.a20 That way, the muscles can burn off the excess energy and normalize the glucose level. The immune system starts working better again, probably because exercise increases the number of leucocytes. Though the details of this stress response are not fully understood, its benefits for our health become evident in study after study. Going for a stroll every day keeps rhinitis and sniffles away, for example. Cornelia Ulrich of the University of Was.h.i.+ngton in Seattle and her colleagues have demonstrated this in a study including overweight and inactive women. Those women who picked up the habit of walking reduced the likelihood of catching a cold by half compared to sedentary women. Ulrich concludes these findings aadd a new facet to the growing literature on the health benefits of moderate exercise.a21 Moderate exercise leads also to more relaxed sleep patterns, which further decreases the stress burden. In tests, people allowed only four hours of sleep for several nights appeared to be testy and responded with elevated levels of stress hormones and glucose in their blood. Once these people were allowed extra sleepa"10 to 12 hours per nighta"the stress signs disappeared.

Exerciseas stress-fighting effects amplify each other and prevent us from premature aging. Physical activity reduces the allostatic load, which is connected with a prolonged life expectancy.

MORE HEALTHY DAYS.

The steady increase of the average life expectancy is a triumph of civilization. At the same time, health-care experts and even citizens themselves are afraid of this trend. They believe the extended life expectancy could just mean that people are going to have long periods of sickness, and thus they talk about something they call aexcess age.a In this view, frail seniors would populate nursery homes and hospitals, and the younger generation would have to take care of them.

It was the physician James Fries of Stanford University who most notably began questioning this grim scenario. In the 1980s he published an essay in the New England Journal of Medicine that opened a completely newa"and very comfortinga"view on the fact that we all grow old. If it was possible to push the onset of age-related diseases back, Fries suggested, and if this gain was larger than the time gained by the increased life expectancy, those extra years would be free of disease and full of healthy and happy days. Thus the period of frailty that often precedes a death would not get longer and would occur later. Fries has proposed the term acompression of morbiditya to describe this potential change.

Stay Healthy Longer Runners stay in good health longer When Fries published his ideas, many people dismissed them as wishful thinking. Some even thought it was a downright dangerous view, and that Friesas theory might prevent society from taking measures to deal with an approaching army of sick seniors. By now, many skeptics know better. The compression of morbidity is a valid concept, and we can experience it, if we begin with regular exercise. Fries and his colleagues have shown this in an impressive study22 that compared 538 people who run regularly (most of them members of a running club) to 423 sedentary people, recruited from the employees at Stanford University. The partic.i.p.ants were age 50 or older when the study began. The researchers tracked them for 21 years.

According to their findings, regular running dramatically slows down the effects of aging. Elderly runners, now in their 70s and 80s, have fewer disabilities, a longer span of active life, and were half as likely as non-runners to die early deaths. Nineteen years into the study, 34 percent of non-runners had died compared with 15 percent of runners. At the beginning of the study, the runners ran an average of about four hours a week. After 21 years, their running time declined to an average of 76 minutes a week, but they were still seeing health benefits from running. Both study groups became more disabled after 21 years of aging, but for runners the onset of disability was later. aRunnersa initial disability was 16 years later than non-runners,aa Fries says. aBy and large, the runners have stayed healthy.a23 The data refer to avid runners. But what about white-collar workers who stop using their bodies by age 30? Is there something like a point of no return, after which the disuse of the body cannot be made up for?

The uplifting answer given by science is: no. Study after study has revealed that even old and habitually sedentary people still can reap the benefits of exercise if they simply put themselves in motion. These late bloomers complain less often about ailments and need fewer medical treatments. Even individuals at ages 70 to 80, who were almost disabled because of lack of exercise, can overcome ailments by systematic training.

James Fries got it right. In our aging societies, regular exercise can push the onset of diseases back to a later point in life, thus multiplying the number of happy and healthy days. n.o.body can avoid growing old. But we can do a lot to keep ourselves from growing old in bad shape.

14.

Panacea for Every Day.

IN THE SOUTHERN PART OF THE CANADIAN PROVINCE OF ONTARIO there is a long-lived group of people whose lives involve heavy physical labor. They belong to a Christian denomination whose founders immigrated to America in the eighteenth century from the Alsace region, the German-speaking parts of Switzerland and Germany. To this day they talk in a German dialect and call themselves aAmischea or aamische Leit.a They hold the belief that they are in this world, but not of this world, and live like their ancestors did roughly 200 years ago.

While other Amish people in North America, such as those in Pennsylvania, have incrementally adopted certain technologies, like tractors, the approximately 500 Amish of the Ontario settlement refrain to this day from using any new technologiesa"which has bestowed an enviable vitality upon them.

This was revealed by David Ba.s.sett, of the University of Tennessee in Knoxville, and the anthropologist Gertrude Huntington, of the University of Michigan in Ann Arbor, who studied the level of physical activity in this group. aThe people stay active when they are much older than 80,a says Huntington.

Usually the Amish from this settlement in Ontario avoid any contact with the surrounding world of the aEnglish.a They are happy that their houses and farms, in a spa.r.s.ely populated area approximately 40 miles south of the vibrant city of Toronto, are overlooked by the rest of the world. Here, no visitors show up to gawk at them, and no one takes photos when they travel the gravel roads in their horse-drawn buggies.

But in this case 48 women and 53 men decided to make an exception. The Amish agreed to physical examinations and carried battery-powered pedometers in their skirts and waistbands for a week.1 The result: on average, the men took 18,425 steps per day, the women 14,196.

The Amish also kept minutes of their day. Within the weeklong period, the women spent 42 hours on moderate-to-hard physical work and walked for five hours. The men labored for 52 hours and walked for 12 hours. This means that the Amish are six times more active than the average inhabitants of the industrialized world. Just 9 percent of the Amish women, and none of the men, were obese. That makes them much slimmer than their Canadian neighbors (where 15 percent of the population is obese) and the inhabitants of the United States (where 31 percent is obese), despite the fact that, like their German-speaking ancestors, they love to eat substantial meals, with meat, potatoes, gravy, and homemade cakes.

Few would demand to abandon engine power and electricity, which would mean forgoing the use of laundry machines, dishwashers, computers, and cars. And yet we can learn from these Amish people in Ontario. They are so busy with physical activity in their daily life that it wouldnat occur to them to go to a place called a agyma to do something for their health. The Amish have succeeded in making physical activity a natural part of their daily ch.o.r.es and work. They are puzzled when they find out that there are people around them who die from insufficient use of their bodies.

BUT WHAT ABOUT GENES?.

Although many inhabitants of the industrialized world have integrated physical activity and sports into their daily lives and benefit from an even healthier (because less austere) life than the Amish, millions have yet to discover the healing power of exercise. One reason is that many people simply underestimate the potential of their own bodies. If the good physical condition of healthy people is pointed out to ailing people of the same age, many of them will dismiss this comparison as unfair, saying their healthier peers have always been physically active. But this line of thought ignores the fact that the benefits of physical activity can be reaped by every person who was born healthy. The body is more potent than most people can imagine. There is no medical or biological reason to retire at age 62, 65, or 68 because studies have revealed that people who are aware how important physical activity is stay more or less at the same level of health between age 55 and 75.

To the extent that people misjudge the bodyas capability to rejuvenate, they overrate the influence of their genes on physical const.i.tution. There is no question that, aside from the lifestyle, the genetic makeup affects fitness and physiological reserves. Yet it is revealing how experts view this. The sports physician Aloys Berg of the University Hospital in Freiburg, Germany, concludes that aeven if there is an unfavorable predisposition, the individual range is large enough so that lifestyle changes can beneficially influence the emergence of risk factors and the onset of chronic diseases.a2 Maria Fiatarone Singh, chair of Exercise and Sport Science at the University of Sydney, puts it this way: aHowever, at least partial escape from a genetic predisposition to type 2 diabetes, stroke, coronary artery disease, hypertension, obesity, and other major scourges of modern civilization is possible with the adoption of realistic doses of physical activity. Much of the typical phenotype of the aged persona"a thinning, curved spine, wasted muscles, and bulging abdominal adipose tissuea"is more closely related to time spent in a gym than to the pa.s.sage of years. Furthermore, body composition is still susceptible to change by anabolic stimuli, particularly robust forms of resistance exercise, in the tenth decade of life, despite a lifetime of sedentary behavior.a3 Fiatarone Singh knows what she is talking about. She is the doctor who encouraged people aged 90 and older to do strength training, giving them back their power.

There is no shortage of studies showing the bodyas potential for renewal. In a study done in Texas in 1966, doctors examined five young men and doc.u.mented their fitness levels. Thirty years later the procedure was repeated, and it became evident that years of sedentary living had reduced their fitness. Next, the men, now aged 50 to 51, were subjected to 24 weeks of endurance training of moderate intensity with jogging, walking, bicycle ridinga"with the result that their decline was fully reversed, and they reached the same level as 30 years before.

The general public usually ignores this capacity for rejuvenation. Our society denies that older people have physical reserves. This ageism can be seen any time younger people start talking more loudly and using simpler vocabulary when addressing an older person. This discriminating approach can lead to a self-fulfilling prophecy. As a result of being treated like idiots, older people indeed start to walk slower, have impaired hearing, and become p.r.o.ne to cardiovascular diseases.

The psychologist Becca Levy at Yale University in New Haven, Connecticut, has studied this phenomenon among 90 healthy elderly persons. At first she tested the memories of these volunteers, then showed them positive attributes about aging, such as awise,a aalert,a alearned,a and asage,a and retested them. Afterward, their memories had improved and the partic.i.p.ants even walked faster.

To check her findings, Levy showed her subjects such negative words as adecrepit,a asenile,a adementia,a and aconfused,a and carried out yet another memory test. Now, their memories were worse, and the partic.i.p.ants walked significantly more slowly.4 A NEGLECTED REMEDY.

Although exercise is one of the most potent and effective remedies in existence, it plays only a small role in medical-school training. For this reason, American doctors rarely recommend exercise. Even though some doctors do prescribe exercise, physicians can make a much greater profit with drugs and operations. Faith in the power of medicine is another reason why people tend to underestimate the value of exercise. The number of back surgeries has increased dramatically in recent years, while pills for high blood pressure and drugs to lower cholesterol have sales in the billions of dollars. This fuels the medical industry and might meet the expectations of many patients, but it still amounts to nothing more than tinkering with the symptoms.

This turn toward big pharmacology and invasive medical procedures is promoted by faulty financial incentives in the health-care system. One example is a booming procedure called angioplasty, which is the mechanical widening of a narrowed or totally obstructed blood vessel. In about 80 percent of these procedures a small tube, a stent, is inserted to keep the vessel open. However, in 20 to 40 percent of angioplasties, the affected area becomes narrowed again.

These results are less good than those produced by a landmark trial published in the journal Circulation.5 In this exercise program the patients had fewer complications, less pain, and their treatment was cheaper. Ignoring these impressive results, many physicians continue to recommend and carry out angioplasties. The procedure, introduced in 1977 by a German radiologist, has grown into an $8 billion annual industry in the United States alone, where it is performed 650,000 to 1 million times a year.6 Even when doctors are willing to use the new science of healing through exercise, they often find that patients would prefer an invasive procedure and drug regimen, rather than the supposedly silly advice of bicycling 30 minutes a day. Obese patients and smokers who cannot be coaxed into changing their behavior repeatedly frustrate such doctors.

Many middle-aged people cannot envision the long-term repercussions of complete physical inactivitya"a life of continual ailments and increasing weight gain: aObesity is not like running through a minefield, which kills you all at once or lets you run through it unscathed,a says David Allison, a biostatistician at the University of Alabama, Birmingham. aInstead, your risk increases over time. What you die of is the acc.u.mulated effects from years of obesity.a7 Fiatarone Singh emphasizes the absurdity of medical practices in industrialized countries: aImagine the 85-year-old woman with cachexia [a wasting condition], congestive heart failure, osteoporosis, depression, recurrent falls, type 2 diabetes, hypertension, peripheral vascular disease, osteoarthritis, insomnia, and functional decline. Whereas a pharmaceutical approach to most of these problems is possible, and would be the usual course of action, the potential for iatrogenesis [further problems caused by the medical treatment], burden for the patient, and cost of such treatment is substantial. If exercise were taken seriously by her doctor, however, and used to its full potential, all of her clinical problems could be addressed in part by the prescription of a tailored exercise regime, which could reduce to a minimum the number and doses of medications needed.a8 The uses of exercise to treat diseases are so novel that many physicians are not taking advantage of them. Yet the paradigm is s.h.i.+fting, and many signs indicate that a new mind-set is gaining ground. In Seattle, the YMCA and Fred Hutchinson Cancer Research Center now offer an exercise program for cancer survivors. The 10-week program, called Exercise and Thrive, is available free to adults who have completed cancer treatment, regardless of where they were treated.9 The American College of Sports Medicine and the American Medical a.s.sociation have now joined forces to launch a program called aExercise Is Medicine,a designed to encourage patients to incorporate physical activity and exercise into their daily routines and to urge doctors to prescribe exercise to their patients.10 aWhy physicians are so quick to accept research data on expensive medications while essentially ignoring even stronger data on the benefits of physical activity is at the core of this program,a says Robert Sallis, a past president of the American College of Sports Medicine. aWe already advise against smoking; recommending exercise should be no different.a11 In Great Britain, general pract.i.tioners are turning to exercise therapy to help people with depression. The Mental Health Foundation, based in London and Glasgow, says that 22 percent of doctors now prescribe exercise therapy as one of their most common treatments for depression, compared to only 5 percent three years ago.12 Having a family doctor talk to patients about the importance of exercise appears to be the most effective way to get people going. It just takes some unorthodox but simple steps. What if doctors gathered their sedentary patients on a certain afternoon of the week and took them on a walk? Patients would be astounded how much their glucose level drops after just a few minutes of brisk walking.

In hospitals and nursing homes, the time is also ripe for change. Being bedridden should no longer be regarded as an inevitable fate but as a side effect of bed rest. Mobilizing patients at risk of being bedridden could be achieved with more and better-educated nursing personnel and improved facilities, including better-designed furniture and rooms. In hospitals especially, there should be more time and money available for training to reverse the disastrous consequences of too much bed rest.

LESS IS MORE.

When people decide to change their lives, they often set themselves unrealistic goals they cannot achieve. They want to become athletic and slim in no time. They go out and buy sneakers and sporting clothes, sign up at the gym, and start with great enthusiasm. This period of euphoria usually lasts four weeks. Then exercise turns into a burden. Month after month, gym fees are charged to credit cards whose owners hardly work out anymore.

Energy Expenditure per Hour There is no need to have such ambitious targets. Fortunately, science shows that surprisingly small amounts of exercise suffice to put health and well-being on the right track. Formerly, exercise recommendations were based on the a.s.sumption that sweat-inducing drudgery was needed to achieve therapeutic effects. But a recent review of 44 studies revealed that most of the good effects start appearing at an intensity corresponding to the burning of 1000 kilocalories per week. Among sedentary adults, even the expenditure of just 500 to 800 kilocalories produces slight improvements.13 One general recommendation is to perform 30 minutes of moderate activity, five or more days per week;14 the exercise can be brisk walking, jogging, or bicycle riding. This amount is apparently enough to meet the evolutionary needs hardwired into our bodies, which are still adapted to the Stone Age. If a person walks for 30 minutes, he or she burns 200 to 250 kilocalories. Doing this five times a week, plus some work in the garden and home, and a person uses nearly 2000 kilocalories per week.

This surprisingly low minimal requirement has two advantages. First, the risk of injury is extremely low, and one need not fear sore muscles. The benefit of this low-intensity exercise is much greater than the potential harm. One can start slowly and increase intensity step by step. People who were completely inactive for years, or who are already sick or ailing in some way, can reclaim their bodies through exercise, though they should talk to a physician before starting to set up an individual training program.

Second, one can get small bits of exercise that in turn add up to the recommended daily total. Each errand we run and each ch.o.r.e we do helps. Weeding, vacuuming, sweeping the sidewalk, climbing stairs, walking to the grocery store: if we integrate such activities into our daily lives, we can reach calorie expenditures large enough to improve existing medical conditions and stave off further diseases.

It is fascinating to see that these good effects often multiply and improve other aspects of life. After adopting an active lifestyle, many people abandon other bad habits; they switch to a balanced diet, reduce the number of cigarettes they smoke, or quit smoking altogether. Furthermore, they sleep better anda"because they lead by examplea"increase the activity of their children.

FIT IS MORE IMPORTANT THAN FAT.

Finally, we benefit from exercise even when we are not losing weight. Overweight men are especially protected against heart attacks by physical activity. Similarly, women who are overweight but active have a slightly lower risk for heart disease than slim but inactive women. Being overweight does not harm oneas healtha"as long as a heavy body is kept in motion.

This is also the message of a recent study by doctors and physiologists at the University of South Carolina in Columbia. 15 They measured the body ma.s.s index, waist circ.u.mference, and body fat of more than 2,600 adults aged 60 years or older, a.s.sessed their fitness by a treadmill exercise test, and followed the group for 12 years. aFitness was a significant mortality predictor in older adults, independent of overall or abdominal adiposity,a the scientists reported in the Journal of the American Medical a.s.sociation. Active heavyweights live longer than inactive slim peoplea"fit is more important than fat. And n.o.body needs to become an athlete. According to the study, walking for 30 minutes on most days of the week already increases the chances to aachieve a healthy lifestyle and to enjoy longer life in better health.a To be sure, these effects can be enhanced. Exercise and health are directly correlated; the more we use our muscles, the bigger the gain. Imagine 60 minutes of moderate exercise, five or more days per weeka"what a treat for body and soul that would that be! This program would also be the right one to fully prevent colon and breast cancer, ideally combined with light strength training two or more days per week.

Still, one should not overtrain the body because there can be too much of a good thing. Regular exercise corresponding to an expenditure of 3,500 kilocalories per week or more can lead to adverse effects.16 Those trying to lose weight by starving themselves for long periods are bound to fail. Our Stone Age genes are programmed in such a way that we long for the juiciest ham and the sweetest fruit. Dieting fads have come and gone for the past 50 years, but a miracle regimen has yet to be found. If a person manages to be on a diet for 15 weeks, he or she can lose up to 24 pounds. Yet the effect usually vanishes within three to five years. It would be much smarter to exercise more while keeping food intake the same or reducing it slightly. If we burn 700 kilocalories more than we consume every day, our weight inevitably goes down, by about one pound per week. I would recommend doc.u.menting this by recording oneas weight every morning.

A WAY OF LIFE.

Physical exercise can help us, whatever we do and wherever we go, as long as we allow it to become our permanent companion. The magic formula is to do a little every day and to establish well-being in small but constant steps. At stake is the maintenance of our bodies. If we asked our dentist which teeth we should floss, he would answer: only those you want to keep. The same is true for physical activity: move those muscles you want to keep.

There are easy ways to make family life more mobile. To start with, children should not have their own television sets in their rooms, and the one in the living room should be switched off most of the time. In our house in Arlington, Ma.s.sachusetts, there are three children and no television. Having been brought up in Europe, I am puzzled to see that many American households have one television set in most of the rooms and, even more disturbing, that the television is sometimes used to babysit toddlers. Americans spend nine times as many leisure hours in front of a screen than being physically active. As we saw earlier, the more time people spend in front of a screen, the more likely they are to develop type 2 diabetes.17 The pediatrician Thomas Robinson at Stanford University examined 192 children at two elementary schools. The students at one of the schools were restricted at home to a maximum of one hour per day watching television. The students of the other had no limita"and seven months later they were more than two pounds heavier and their waistlines had increased by an average of one inch.18 Another way to get started is to begin with small changes, like 60 seconds of exercise per day. This might seem ridiculous, but the trick is to train two minutes per day in the second week, three minutes per day in the third week, and so on. Half a year later, you will be a presentable athlete and need only to maintain your level. There are also many ways to integrate muscle use with daily life: walk your children to school; avoid escalators and elevators; switch to public transportation and get off the train or bus a few stops earlier, walking the remaining distance. People living in Manhattan are slimmer than the average American, no doubt in part because they walk more. Also, get rid of your second (and third) car and see if you can commute to work by bike. Or join community groups that engage in walking and other physical activities.

When it comes to judging the amount of exercise we get, itas human nature that we tend to deceive ourselves. We perceive even decades of inactivity as an atypical period that will soon be over: aOnce I get a promotion . . . once the baby is older . . . once we move nearer to the city.a We persistently think of ourselves as more athletic than we actually are. Perhaps we should follow the example of the Amish who agreed to walk around with pedometers. The devices cost around $15 to $20, sense body motion, and count footsteps. This count is converted into distance by knowing the length of your normal stride. Wearing a pedometer and recording your daily steps and distance can be a good motivating tool. If you have taken about 10,000 steps by evening, you can put your feet up and be happya"you have done your daily stint.