If you’re trying to lose weight, you’ve probably heard that including harder runs in your training will help, because your metabolism will stay more revved up post-run than after an easy jog. A new small study provides a reminder that a hard run isn’t carte blanche to eat everything in sight.
For the study, 18 women did four 30-minute treadmill sessions. The workouts’ intensity ranged from low to moderate to vigorous.
After the workouts, the women were asked to estimate how many kilojoules they had burned during each. After the hardest of the four workouts, the women overestimated their energy expenditure by 18 per cent.
“The ability to accurately estimate energy expenditure seems to be compromised when engaging in vigorous exercise,” the researchers who conducted the study concluded. “This mismatch could have deleterious effects on weight management over the long term.”
Many runners, of course, find that they have little or no appetite immediately after a hard run. This study suggests that, once you regain your appetite, you might feel justified in eating significantly more than after a lower-intensity run of the same length.
One way to avoid this weight-loss-sabotaging sequence of events is to take in a small amount of kilojoules as soon as your stomach feels settled after a hard run. This should lessen the chance of feeling famished later, and will also help speed your recovery from the hard workout.
The research was presented at the annual meeting of the American College of Sports Medicine.