How much exercise matters more than how hard you exercise

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How much exercise matters more than how hard you exercise

http://www.medicalnewstoday.com/medicalnews.php?newsid=31875

The amount of exercise a person engages in per week may be more

important than the intensity of the exercise. A study in the October

issue of CHEST, the peer-reviewed journal of the American College of

Chest Physicians (ACCP), shows that adults who participate in mild

exercise, such as walking briskly for 12 miles or exercising for 125

to 200 minutes a week at moderate intensity can significantly improve

their aerobic fitness and reduce their risk of cardiovascular

disease. Unlike most exercise interventions, this finding suggests

that amount may be equally or more important as exercise intensity.

" The classic exercise regimen has a component of intensity up to 80

percent of someone's maximum for health benefits. Our study

demonstrates that you can exercise at an intensity much less than

that and still achieve fitness benefits, " said lead author D.

Duscha, Duke University Medical Center, Durham, North

Carolina. " People find exercise `hard' and few people want to

exercise at an intensity higher than they have to. Walking briskly

for 12 miles a week per week is realistic and does not require anyone

to incorporate a hardcore training regimen. Increasing your mileage

or intensity will give you even greater health benefits. "

Researchers from Duke University Medical Center examined the effects

of different exercise training regimens on 133 sedentary, overweight,

nonsmoking patients, ages 40 to 65 years, who had abnormal levels of

fat in their blood. Patients were divided into four exercise groups:

high-amount/high-intensity (HAHI), the equivalent of jogging 20 miles

per week at 65 to 80 percent peak VO2; low-amount/high-intensity

(LAHI), the equivalent of jogging/walking up an inclined treadmill

approximately 12 miles per week at 65 to 80 percent peak VO2; low-

amount/moderate intensity (LAMI), the equivalent of walking

approximately 12 miles per week at 40 to 55 percent peak VO2; and a

control group of nonexercising patients. All patients underwent

cardiopulmonary exercise testing twice at baseline and after 7 to 9

months of exercise training.

All exercise groups significantly improved their absolute and

relative peak oxygen consumption and time to exhaustion (TTE)

compared to baselines scores. Although the HAHI group showed the

greatest improvements in peak VO2 overall, increasing exercise

intensity from 40 to 55 percent to 65 to 80 percent (at a controlled

amount of 12 miles/week) did not significantly improve peak oxygen

consumption, yet increasing the amount of exercise did produce

improvements. An increase in exercise amount also demonstrated a

graded increase in TTE between groups, although data were not

statistically significant.

" Although our results did point toward amount being more important,

it is very likely fitness levels can be improved by increasing either

amount or intensity, " said Duscha. " This is illustrated by the tiered

effect the exercise dose had on fitness improvements across our

groups. We believe with more people in the study, increasing

intensity would also have been significant. "

Body mass index (BMI) was reduced in the LAHI and HAHI, groups but

remained unchanged in the LAMI group. All exercise groups lost an

average of 2.87 pounds after exercise. Baseline characteristics of

age, BMI, weight, peak and relative VO2, and TTE were not different

between the groups.

" A second very important message is that subjects enjoyed fitness

benefits in the absence of weight loss. Many people exercise with the

purpose of losing weight. When they do not lose weight, they do not

think the exercise is benefiting them and they stop exercising, " said

Duscha. " The truth is, you can improve your cardiovascular fitness

and reduce your risk for heart disease by exercising without losing

weight. Even if individuals do not lose weight, it is likely that

they will lose body fat and increase lean muscle mass while reducing

other risk factors. "

Researchers stress that adherence to exercise requires motivation and

making exercise a priority. When beginning an exercise regimen,

researchers recommend starting slow, choosing an activity that you

like, and making exercise a social activity. For individuals with a

known illness or medical problems, consulting a physician before

starting an exercise program is also recommended.

" If you distill our results down, the public health message is: You

only need to walk briskly for 12 miles per week or for approximately

125 to 200 minutes per week to improve your health, " said

Duscha. " This sheds more light on the question, What is the minimum

amount of exercise I need to do to get a health benefit?'

" Regular exercise is an important part of a well-balanced lifestyle, "

said A. Kvale, MD, FCCP, President of the American College of

Chest Physicians. " Physicians and other health-care providers should

encourage their patients to engage in regular exercise in order to

obtain pulmonary and cardiovascular benefits. "

CHEST is a peer-reviewed journal published by the ACCP. It is

available online each month at www.chestjournal.org. ACCP represents

16,500 members who provide clinical respiratory, sleep, critical

care, and cardiothoracic patient care in the United States and

throughout the world. The ACCP's mission is to promote the prevention

and treatment of diseases of the chest through leadership, education,

research, and communication.

For more information about the ACCP, please visit the ACCP Web site

at http://www.chestnet.org