Part 4 (2/2)
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.
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