As Little as 72 Weekly Minutes of Moderate Exercise May Help
May 15, 2007 -- Short on time for exercise? Getting fitter may not put as much of a dent in your schedule as you think.
That's nearly half the minimum amount of moderate exercise recommended by the CDC and other health organizations.
When it comes to exercise, the rule of thumb appears to be that "even a little is good; more may be better!" exclaims an editorial published with the new study in The Journal of the American Medical Association.
First, the women tested their aerobic fitness on a stationary bike, pedaling as hard as they could while cranking up the resistance on the bike.
Next, the researchers -- who included Louisiana State University's Timothy Church, MD, PhD, MPH -- randomly split the women into four groups.
Three of the four groups were assigned to get moderate-intensity exercise on a stationary bike or treadmill three or four times per week for six months.
Those three groups varied in their amount of prescribed weekly exercise. One group exercised for 72 minutes per week. Another group worked out for 136 minutes per week. The third group worked out for 192 minutes per week.
For comparison, women in the fourth group weren't assigned to exercise.
Assigned workouts were done under expert supervision. That way, the researchers made sure that the women followed their exercise assignments.
The women also got up to $350 in financial incentives to stick with the study. They got less money if they missed a week of workouts. Most women saw the study through to the end.
At the end of the six-month study, the women repeated the fitness test. The results show that all of the exercise groups had boosted their aerobic fitness.
Compared with the no-exercise group, average scores on the fitness test improved by 4% for the women who worked out for 72 minutes per week, by 6% for women who worked out for 136 minutes per week, and 8% for women who worked out for 192 minutes per week.