The study, by researchers at the University of Copenhagen, looked at the effects of increasing aerobic exercise in healthy, inactive, moderately overweight young men.
Three groups were established and assigned to remain inactive, exercise 30 minutes day or exercise 60 minutes a day, respectively. According to the New York Times, they were also asked not to change their diets, and to keep detailed daily food diaries, as well as being monitored on random days with a motion sensor to determine how active they were when not doing their assigned exercise.
Researchers then looked at participants’ percentage of fat and muscle and compared how much exercise they did to what they actually achieved in terms of weight loss.
The results were surprising.
While both the moderate and high-intensity exercisers did lose some weight, those who worked out only 30 minutes a day actually lost more weight than those exercising 60 minutes a day. Those who were sedentary (not surprisingly) didn’t lose any weight.
“A similar body fat loss was obtained regardless of exercise,’ the study’s authors wrote.
While the researchers could not confirm why the group who worked out 30 minutes each day lost more weight (7 lbs on average, compared to 5 lbs), they suggest that the group who worked out for 60 minutes each day was eating more. (Food diaries for this group did indicate an increase in calories, however, it wasn’t necessarily enough to account for the lack of weight loss.) A second theory suggests that the group working out for 60 minutes each day was fatigued, and as a result, less active throughout the day. (This was confirmed by motion sensors that the study participants were asked to wear, which showed that the 60-min group was sitting more.)
Whatever the reason, it seems as though 30 minutes of exercise is the perfect amount for weight loss’it’s enough to burn calories, but not enough to make a person feel as though they need to refuel and replace the calories spent during a workout. [*Updated added on Sept. 21, 2012]
Personally, I’m glad this study shows it’s not necessary to exercise an hour a day to achieve results. I love exercising’but not for an hour at a time. I find that biking to work, going for a walk at lunch and doing yoga a few times a week is more sustainable than trying to exercise too much, which just makes me feel overwhelmed.
What about you? Do you exercise 30 minutes a day, or more? What do you find has the best results/is the most sustainable?
-Katharine Watts, Associate Web Editor; Image:iStock