Get off the computer and out to exercise in your free time!

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Get off the computer and out to exercise in your free time!

03 May 2005 Medical News Today

Do you - like millions of full-time workers - surf TV channels, play

video games or boot up the computer in what little free time you

have? If so, there's a good chance you're skimping on heart-healthy

physical activities, scientists report at the American Heart

Association's 45th Annual Conference on Cardiovascular Disease

Epidemiology and Prevention.

In their study of nearly 4,500 men and women, a subset of full-time

workers who spent more of their down time engaged in sedentary

activities had significantly less exercise than part-time workers

with the same amount of sedentary leisure pursuits.

" Many full-time workers say that one of the biggest barriers to

getting enough exercise is that there's not enough time in the day, "

said study author Meghan Warren, P.T., M.P.H., a pre-doctoral fellow

in the division of epidemiology and community health at the

University of Minnesota, Minneapolis. " If they shift their interests,

they would have more time for physical activity. "

Many studies found that exercise can help prevent obesity, heart

disease and other health problems. Warren's team evaluated the

association between sedentary behaviors, physical activity and

fitness using data from the large, population-based 1999-2000

National Health and Nutrition Examination Survey (NHANES) conducted

by the National Center for Health Statistics, one of the Centers for

Disease Control and Prevention. The survey asked the 4,498 adults if

they participated in 48 different leisure-time physical activities,

including walking, basketball, swimming and cycling, in the past 30

days. The 2,353 participants who indicated they participated in at

least one of these activities were also asked how many minutes, on

average, they engaged in each activity per session.

As part of NHANES, participants were also asked about three sedentary

activities: watching TV, playing video games and leisure-time

computer use. " The 1999-2000 survey was one of the first to ask about

computer use and video games so that gave our study a more complete

assessment of sedentary activities than studies in the past, " Warren

said.

The researchers assigned each activity a metabolic equivalent or MET,

a standard, published measure of physical activity intensity. A MET

level of 1-3 corresponds to low-intensity activity such as watching

TV or sleeping; a MET value of 3-6 corresponds to moderate-intensity

activity such as walking or cycling; and a MET value of 6 and over

corresponds to vigorous activity such as running or skiing. Then, for

each leisure-time activity, Warren's team calculated the MET-hours

per day, based on frequency, duration and intensity of activities.

When the researchers looked at all 2,353 participants who reported

any leisure-time physical activity, the analysis showed no

statistically significant association between the amount of time

spent in sedentary leisure activities and that spent exercising.

But when they compared two subgroups, 1,573 full-time workers and 508

part-time workers, a different picture emerged for those who spent

the most time in sedentary activities.

Full-time workers with five or more hours of sedentary activity per

day engaged in about 11 fewer minutes of physical activity such as

walking or cycling each day compared to full-time workers who didn't

spend any time watching TV, playing video games or using the computer

in their off hours, a statistically significant finding.

In contrast, part-time workers who spent five or more hours per day

engaging in sedentary activities showed a trend toward engaging in

about 11 more minutes of physical activity each day than part-time

workers who avoided sedentary activities in their free time. The

finding did not reach the level of statistical significance, perhaps

because of the smaller number in that group, she said.

" Full-time workers have less free time, so the more time spent in

sedentary activity, the less time they have to exercise, " Warren

said. " Part-time workers have more discretionary time -- so it could

be that those that watched more TV, exercised more too. "

Some studies in children reveal a trend similar to that seen in part-

time workers, she said. " That makes sense as both have more free

time. " Nearly 30 percent of the participants also took a treadmill

test to determine their physical fitness, as measured by VO2 max, the

maximal volume of oxygen exchanged during exercise. In this subgroup

of 1,319 men and women, those who spent five or more hours watching

television or using the computer during their time off were slightly

less physically fit than those who didn't spend any time engaging in

leisure-time sedentary activities.

All the analyses took into account factors that could skew the

results, such as gender, body mass index, age, race, education and

marital status.

Since this was an observational study, Warren said she doesn't know

whether full-time workers exercise less because they are watching too

much TV or vice versa. " But either way, they need to think about

shifting their interests. "

Co-authors include J. M. Oakes, Ph.D., and H. Schmitz, Ph.D.,

M.P.H.

Statements and conclusions of study authors that are presented at

American Heart Association scientific meetings are solely those of

the study authors and do not necessarily reflect association policy

or position. The American Heart Association makes no representation

or warranty as to their accuracy or reliability.

NR05 - 1050 (Epi/Warren)

Abstract P284 (EPI)

American Heart Association

http://www.americanheart.org