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Moderate Exercise: No Pain, Big Gains

Harvey Simon, MD

Medscape Internal Medicine. 2006;8(1) ©2006 Medscape
Posted 03/28/2006

Introduction

America is in the grip of an energy crisis. The rising costs and dwindling
supplies of fossil fuels get all the press, but from a medical point of view,
the real crisis involves human energy -- or the lack thereof. In the United
States, and throughout the industrial world, insufficient exercise is a major
cause of morbidity and mortality. In America, it is an important contributor to
4 of the 6 leading causes of death: heart disease, cancer, stroke, and diabetes.
In all, a sedentary lifestyle accounts for some 250,000 premature deaths
annually.[1] That means that 12% of all the deaths in America are caused by
sloth, as are 23% of our chronic illnesses. It's a staggering burden of death,
disability, and expense, and it's all the more tragic because it's unnecessary.

Modern epidemiologic, clinical, and laboratory studies have been documenting the
health benefits of exercise for nearly 50 years, but fewer than 25% of Americans
get the exercise that they need. What accounts for the gap between theory and
practice?

In part, we are victims of our own success. Before the industrial revolution,
about a third of all the energy used in American agriculture and manufacturing
was provided by human muscles; now, that contribution is minuscule. We don't
exercise because we no longer have to.

Cultural preferences and economic pressures add to the problem. The average
American adult spends 170 minutes a day watching TV and movies and 101 minutes a
day driving, but less than 19 minutes a day exercising.[2] Spectator is a kind
word for it; we are truly a nation of couch potatoes.

Healthcare professionals can't do much about our entertainment industry,
advertising empire, or economic imperatives. And even if we could turn back from
the information age, few would want to. But we can, and should, deal with
another set of barriers to healthful exercise. In fact, our profession has
erected some of these barriers. The first is the confusing mix of exercise
guidelines and recommendations; for example, the US Surgeon General currently
advocates 30 minutes of moderate exercise a day, whereas the Institute of
Medicine calls for 60 minutes a day and the 2005 Dietary Guidelines for
Americans recommends 30-90 minutes a day. The second barrier has its roots in
the very movement that puts exercise on the map, the aerobics revolution.
The Aerobics Doctrine

The scientific study of exercise blossomed in the 1960s and 1970s. Its principal
research tool was the maximum oxygen uptake test, which measures the amount of
oxygen taken up by the lungs, pumped by the heart, and delivered to the muscles
during maximal exertion on a treadmill or bicycle ergometer. Improvements in the
maximum oxygen uptake, or VO2 max, quickly became the gold standard for judging
the efficacy of exercise.

Research in many labs demonstrated that optimal improvement in VO2 max depends
on rather vigorous exercise. The best results come from exercise that is intense
enough to raise the heart rate to 70% to 85% of its maximum, prolonged enough to
sustain that intensity for 20-60 minutes continuously, and frequent enough to
occur 3-7 times a week. The aerobics doctrine was born.

In 1975, the American College of Sports Medicine issued its first exercise
guidelines. They called for all healthy adults to exercise at aerobic intensity
(60% to 90% of maximum) continuously for 20-30 minutes at least 3 times a week.
These standards were soon adopted with only minor modification by the American
Heart Association and the US Department of Health, Education, and Welfare, and
they remained in effect for more than 2 decades.
Unintended Consequences

The aerobics doctrine gained acceptance just as Frank Shorter, Bill Rodgers, and
Joan Benoit Samuelson showed that Americans could run. Running became the emblem
of aerobic exercise, and the marathon was installed as the icon of success.
Despite extraordinary individual achievements, however, the aerobics revolution
did not succeed in getting our nation off its duff.

The aerobics doctrine inspired the few but discouraged the many. I was one of
the lucky ones who discovered the benefits (and pleasures) of distance running.
But I also was one of the guilty parties. On the basis of the data at hand and
with the best of intentions, I proclaimed that the only way to benefit from
exercise was to exercise aerobically. In many publications, both professional
and popular, I wrote that golf was the perfect way to ruin a 4-mile walk -- but
I was wrong.

The aerobics doctrine was based on sound studies that showed that aerobic
training is required to build optimal aerobic fitness. Epidemiologic studies
soon confirmed that fit people are healthy people, with a reduced risk for
coronary artery disease, hypertension, stroke, and diabetes and a reduced
mortality rate. These data remain valid today: Aerobic-intensity training is
excellent for fitness and health.[3]
Health Benefits of Moderate Exercise

Without contradicting the value of aerobics, new data show that it is possible
to attain nearly all of the health benefits of exercise without attaining high
levels of aerobic fitness. Moderate exercise is the way to do it. In this
formulation, intensity is less important than the net amount of exercise, and
intermittent exercise is as effective as continuous activity. In fact, golf is
very beneficial indeed, as long as players walk the course and play 2-3 times a
week.[4]

For most people, aerobic exercise is daunting. Moderate exercise should be much
more appealing and accessible, but the message has not yet produced results.
Part of the problem, I think, is the lingering belief that moderate exercise is
a distant second-best to aerobics, that walking is a pale imitation of running.
I suspect that when most people think of exercise, be they healthcare
professionals or other folks, they hear the distant voice of their old coach
barking, "No pain, no gain." For the 100-yd dash, your coach was right, but for
achieving and maintaining health moderate, painless exercise is extraordinarily
beneficial.

Table 1 summarizes 22 studies showing how moderate exercise influences the risk
for cardiovascular disease and mortality. Encompassing more than 320,000 people
from around the world, the studies are eye-opening.

Because all but one of the studies summarized in Table 1 are observational
studies, they cannot prove a cause-and-effect relationship between a particular
physical activity and an observed benefit. Still, I think that it's highly
likely that a causal relationship exists. Scientists have demonstrated clear
health benefits of exercise in animal models. Randomized clinical trials in
humans prove that regular exercise can produce a broad range of physiologic
changes and improvements in risk factors (cholesterol, blood sugar, body fat,
blood pressure, etc) that can be expected to improve health and reduce the risk
for many diseases.[3] Moreover, the large number of observational population
studies from around the world suggest strongly that the biological plausibility
of benefit is a clinical reality.

Although we don't have the advantage of randomized clinical trials that evaluate
the effects of exercise on cardiac events and mortality in healthy people, 48
such trials have been conducted in patients with proven coronary artery disease.
According to a meta-analysis of these studies, about half of the 8940 patients
were randomly assigned to receive the best medical and surgical care available,
whereas the others got the same standard of care plus enrollment in cardiac
rehabilitation programs that were based on moderate exercise. The exercisers
came out on top; in all, they enjoyed a 26% reduction in the risk for death from
heart disease and a 20% reduction in the overall death rate.[5] It's powerful
evidence that exercise protects the heart -- and what's good for ailing hearts
should be at least as beneficial for healthy ones.

If cardiovascular risk reduction was the only benefit of moderate exercise, it
would still be vitally important for every physically able individual. But there
are many other benefits. Exercise is an essential partner with diet for people
who need to lose weight. And many observational studies also suggest that
"no-sweat" exercise can help reduce the risk for stroke (by 21% to 34%),
diabetes (16% to 50%), dementia (15% to 50%), fractures (40%), breast cancer
(20% to 30%), and colon cancer (30% to 40%).[2,3]

If that's not enough to get Americans moving, consider that exercise is also the
only known way to slow the physiologic changes associated with the aging process
in humans.[6] None of these benefits require aerobic intensity; in science, as
in the fable, the tortoise will do very nicely indeed.

A 2005 analysis of data from the famed Framingham Heart Study reports that
people who exercise regularly enjoy 3.7 years of additional life expectancy as
compared with sedentary individuals.[7] An intensity equivalent to walking at a
pace of 17 minutes per mile was sufficient. And another 2005 study showed that
moderate exercise (walking 8.6 miles a week at 40% to 55% of maximum) will even
increase the VO2 max (although not to the same degree as aerobic training).[8]
Cardiometabolic Exercise

One of the barriers to getting our patients moving is the academic distinction
between exercise (defined as formal structured activity designed to promote
fitness) and physical activity (defined as everything else). In our busy world,
most people do not believe that they are able to set aside time for formal
exercise, especially intense workouts. In fact, the distinction is both
arbitrary and misleading. Any physically active undertaking will contribute to
health if it is part of an active lifestyle. Raking the lawn and cross-country
skiing are at opposite poles of a single spectrum of benefit. For maximum
protection, activities at the low end of the spectrum require more time than
those at the high end, but they also are safer and less likely to produce
injuries -- and the health benefits are remarkably similar.

What should we call the broad spectrum of activities that contribute to health?
The familiar terms (aerobic, anaerobic, endurance, isometric, and isotonic) are
not quite right. That's why I've proposed the term cardiometabolic exercise
(CME) to emphasize the health benefits of everything from moderate activity to
aerobic training, from washing the car to hitting the elliptical.[2] And the
term is meant to emphasize that even at the low end of the spectrum, exercise
has major benefits for the cardiovascular system (coronary artery disease,
hypertension, stroke, arrhythmias, peripheral artery disease, etc) and
metabolism (body fat, glucose homeostasis and insulin levels, lipids, etc).

Coining a term is one thing, but setting realistic goals is another. Health
professionals have access to a rich literature that evaluates the intensity of
exercise in units, such as metabolic equivalent, kilojoules, and kilocalories.
But to help patients (and their healthcare providers) understand the relative
value of various activities, I've translated these units of measurement into a
simple CME point system and assigned the points to various recreational and
daily activities (see Table 2 ).

The CME system should help people set realistic individual goals instead of
wondering what to make of "guidelines" that call for 30-90 minutes of exercise a
day. For general health and gradual weight loss, aim for 150 points a day or
about 1000 points a week. For faster weight loss, reduce dietary calories more
sharply and/or aim for 300 CME points a day.

The system encourages people to view physically active tasks as opportunities,
not punishments. Climbing stairs instead of riding the elevator is but one
example of a healthful choice that incorporates exercise into the fabric of
daily life. We should encourage our patients to choose whatever activities work
for them as long as they get enough exercise to maintain good health. As people
experience the subjective benefits of moderate exercise, some will go on to
aerobic training or sports participation.

People with medical problems or special needs require additional screening and
supervision; guidelines are available for health professionals and the
public.[2]

CME is the key to exercise for health, and many people will get extra benefit by
adding exercise for strength, flexibility, or balance at home for just a few
minutes a day -- not necessarily at a gym under the watchful eye of a
trainer.[2] In addition, a prudent diet is an essential partner in the lifestyle
prevention of many of the chronic illnesses that plague industrial societies.

Medical science continues to make astounding advances, but it has taken the
collective effort of many dedicated scientists to bring us back to the wisdom of
Hippocrates: "If we could give every individual the right amount of nourishment
and exercise, not too little and not too much, we would have found the safest
way to health."

Harvey B. Simon's, MD, FACP, newest book, The No Sweat Exercise Plan. Lose
Weight, Get Healthy, and Live Longer, was published by McGraw-Hill in 2006 (see
Figure).

Figure.



For more information, visit www.health.harvard.edu

Table 1. No Pain, Big Gains: Some Recent Studies of Moderate Daily Activities


Population Group Type and Amount of Activities Observed Benefit
10,269 Harvard alumni Walking at least 9 miles a week 22% lower death rate
Climbing at least 55 flights of stairs a week 33% lower death rate[9]
836 residents of King County, Washington Gardening at least 1 hour/week 66%
lower risk for sudden cardiac death
Walking at least 1 hour/week 73% lower risk for sudden cardiac death[10]
1453 middle-aged Finnish men At least 2.2 hours of leisure time activity
a week 69% lower risk for heart attack
4484 Icelandic men aged 45-80 Spending at least 43 minutes a day on leisure
time physical activity after age 40 16% lower risk for stroke[11]
73,743 American women aged 50-79 Walking for at least 2.5 hours per week
30% lower risk for cardiovascular events[12]
44,452 American male health professionals Walking at least 30 minutes/day
18% lower risk for coronary artery disease
39,372 American female health professionals Walking at least 1 hour/week
51% lower risk for coronary artery disease[13]
72,488 American female nurses Walking at least 3 hours/week 35% lower risk
for heart attack and cardiac death
34% lower risk for stroke[14]
30,640 Danish men and women aged 20-93 Spending 2-4 hours/week on light
leisure time activity 32% lower mortality rate[15]
4311 British men aged 40-59 Performing light-to-moderate physical activity
35% to 39% lower mortality rate[16]
1404 female residents of Framingham, Massachusetts Performing moderate
physical activity 37% lower mortality rate[17]
802 Dutch men, aged 64-84 Walking or biking at least 1 hour/week 29% lower
mortality rate[18]
707 retired Hawaiian men, aged 61-81 Walking at least 2 miles/day 50% lower
mortality rate[19]
9518 older American women Walking up to 10 miles/week 29% lower mortality
rate[20]
229 postmenopausal American women Walking 1 mile/day or more (a 10-year
randomized clinical trial) 82% lower risk for heart disease[21]
7951 pairs of Finnish twins Exercising at least 30 minutes on at least 6
days/month 43% lower mortality rate[22]
6017 Japanese men, aged 35-60 Walking (to work) for 21 minutes or more on
work days 29% lower risk of developing hypertension[23]
1645 Americans aged 65 and older Walking more than 4 hours/week 27% lower
mortality rate
31% lower risk for hospitalization for heart disease[24]
3206 Swedish men and women aged 65 and older Performing physical activity
at least once a week 40% lower mortality rate[25]
3316 Finnish men and women with type 2 diabetes Performing moderate leisure
time physical activity 18% lower mortality rate[26]
1204 Swedish men and 550 women aged 45-70 Walking or performing demanding
household work 54% (men) and 84% (women), lowers risk for heart attacks[27]
2229 European men and women aged 70-90 Performing moderate physical
activity 37% lower mortality rate

Source: Simon HB. The No Sweat Exercise Plan. Lose Weight, Get Healthy, and
Live Longer. New York: McGraw-Hill; 2006.


Table 2. CME Points for Selected Activities


Activity Pace Duration CME Points
Daily Activities
Carpentry Moderate 30 minutes 100
Cleaning Heavy 30 minutes 150
Digging in yard Moderate 30 minutes 190
Dusting Moderate 30 minutes 75
Mowing lawn Pushing hand mower 30 minutes 200
Pushing power mower 30 minutes 145
Raking lawn Moderate 30 minutes 130
Sexual activity Conventional, familiar partner 15 minutes 25
Stair climbing Moderate, upstairs 10 minutes 100
Moderate, downstairs 10 minutes 30
Washing car by hand Moderate 30 minutes 100
Recreational Activities
Aerobic dance Moderate 30 minutes 200
Biking Moderate 30 minutes 250
Calisthenics Moderate 30 minutes 130
Golfing Pulling clubs 30 minutes 145
Jogging 12 minutes/mile 30 minutes 200
Rope jumping Moderate 15 minutes 200
Skiing Downhill or water 30 minutes 200
Cross-country 30 minutes 315
Swimming Moderate 30 minutes 230
Tennis Doubles 30 minutes 160
Singles 30 minutes 200
Walking Moderate 30 minutes 125
Yoga (Hatha) Moderate 30 minutes 130

CME = cardiometabolic exercise
Source: Excerpted from Tables 4.2 and 4.3 in Simon HB. The No Sweat
Exercise Plan. Lose Weight, Get Healthy, and Live Longer. New York: McGraw-Hill;
2006.




References

1. Myers T. Exercise and cardiovascular health. Circulation. 2003;107:e2.
2. Simon HB. The No Sweat Exercise Plan. Lose Weight, Get Healthy, and Live
Longer. New York: McGraw-Hill; 2006.
3. Simon HM. Diet and exercise. In: Dale DC, Federman D, eds. ACP Medicine.
New York: WebMD; 2006.
4. Parkarri J, Natri A, Kannus P, et al. A controlled trial of the health
benefits of regular walking on a golf course. Am J Med. 2000;109:102.
5. Taylor RS, Brown A, Ebraham S, et al. Exercise-based rehabilitation for
patients with coronary heart disease: systemic review and meta-analysis of
randomized controlled trials. Am J Med. 2004;116:682.
6. McGuire DK, Levine BD, Williamson JW, et al. A 30-year follow-up of the
Dallas bedrest and training study: II. Effect of age on cardiovascular
adaptation to exercise training. Circulation. 2001;104:1358.
7. Franco OH, Laet C, Peeters A, et al. Effects of physical activity on life
expectancy with cardiovascular disease. Arch Intern Med. 2005;165:2355.
8. Duscha BD, Slentz CA, Johnson JL, et al. Effects of exercise training
amount and intensity on peak oxygen consumption in middle-age men and women at
risk for cardiovascular disease. Chest. 2005;128:2788.
9. Sesso HD, Paffenbarger RS, Ha T, Lee IM. Physical activity and
cardiovascular disease risk in middle-aged and older women. Am J Epidemiol.
1999;150:408-416. Abstract
10. Lemaitre RN, Siscovick DS, Raghunathan TE, Weinmann S, Arbogast P, Lin
DY. Leisure-time physical activity and the risk of primary cardiac arrest. Arch
Intern Med. 1999;159:686-690. Abstract
11. Agnarsson U, Thorgeirsson G, Sigvaldason H, Sigfusson N. Effects of
leisure-time physical activity and ventilatory function on risk for stroke in
men: the Reykjavik Study. Ann Intern Med. 1999;130:987-990. Abstract
12. Manson JE, Greenland P, LaCroix AZ, et al. Walking compared with vigorous
exercise for the prevention of cardiovascular events in women. N Engl J Med.
2002;347:716-725. Abstract
13. Lee IM, Rexrode KM, Cook NR, et al. Physical activity and coronary heart
disease in women: is "no pain, no gain" passe? JAMA. 2001;285:1447-1454.
14. Manson JE, Hu FB, Rich-Edwards JW, et al. A prospective study of walking
as compared with vigorous exercise in the prevention of coronary heart disease
in women. N Engl J Med. 1999;341:650-658. Abstract
15. Andersen LB. Relative risk of mortality in the physically inactive is
underestimated because of real changes in exposure level during follow-up. Am J
Epidemiol. 2004;160:189-195. Abstract
16. Wannamethee SG, Shaper AG, Walker M. Lancet. 1998;351:1603-1608. Changes
in physical activity, mortality, and incidence of coronary heart disease in
older men
17. Sherman SE, D'Agostino RB, Silbershatz H, et al. Physical activity and
mortality in women in the Framingham Heart Study. Am Heart J. 1994;128:879-884.
Abstract
18. Bijnen FC, Caspersen CJ, Feskens EJ, et al. Physical activity and 10-year
mortality from cardiovascular diseases and all causes: the Zutphen Elderly
Study. Arch Intern Med. 1998;158:1499-1505. Abstract
19. Hakim AA, Petrovitch H, Burchfiel CM, et al. Effects of walking on
mortality among nonsmoking retired men. N Engl J Med. 1998;338:94-99. Abstract
20. Gregg EW, Cauley JA, Stone K, et al. Relationship of changes in physical
activity and mortality among older women. JAMA. 2003;289:2379-2386. Abstract
21. Pereira MA, Kriska AM, Day RD, et al. A randomized walking trial in
postmenopausal women: effects on physical activity and health 10 years later.
Arch Intern Med. 1998;158:1695-1701. Abstract
22. Kujala UM, Kaprio J, Sarna S, et al. Relationship of leisure-time
physical activity and mortality: the Finnish twin cohort. JAMA.
1998;279:440-444. Abstract
23. Hayashi T, Tsumura K, Suematsu C, et al. Walking to work and the risk for
hypertension in men: the Osaka Health Survey. Ann Intern Med. 1999;131:21-26.
Abstract
24. LaCroix AZ, Leveille SG, Hecht JA, et al. Does walking decrease the risk
of cardiovascular disease hospitalizations and death in older adults? J Am
Geriatr Soc. 1996;44:113-120.
25. Sundquist K, Qvist J, Sundquist J, et al. Frequent and occasional
physical activity in the elderly: a 12-year follow-up study of mortality. Am J
Prev Med. 2004;27:22-27. Abstract
26. Hu G, Eriksson J, Barengo NC, et al. Occupational, commuting, and
leisure-time physical activity in relation to total and cardiovascular mortality
among Finnish subjects with type 2 diabetes. Circulation. 2004;110:666-673.
Abstract
27. Fransson E, De Faire U, Ahlbom A, et al. The risk of acute myocardial
infarction: interactions of types of physical activity. Epidemiology.
2004;15:573-582. Abstract


Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School,
Boston, Massachusetts; Physician, Department of Medicine, Massachusetts General
Hospital, Boston, Massachusetts

Disclosure: Harvey Simon, MD, has disclosed no relevant financial relationships.