Exercising between 7 a.m. and 9 a.m. has been associated with having a lower waist circumference and body mass index than people who work out during midday or evening, according to a study published Tuesday in the journal Obesity.
“This is exciting new research that is consistent with a common tip for meeting exercise goals — that is, schedule exercise in the morning before emails, phone calls or meetings that might distract you,” said Rebecca Krukowski, a clinical psychologist with expertise in behavioral weight management who wasn’t involved in the study, in a news release.
Based on previous studies, the authors noted, morning exercisers have been more likely to have a lower daily caloric intake and passively expend more energy when they’re not exercising. That may sound contradictory, but this tendency likely occurs because working out in a fasted state in the morning means your body is relying on stored fat for energy rather than stored glucose from food. This may mean early birds’ bodies are better equipped for increasing fat oxidation, or burning, both during the exercise and over the following day, even if they’re sedentary post-workout.
