ROCKVILLE, Md. — Want to lose weight? It’s time to become an early riser. A new study finds engaging in moderate to vigorous exercise between 7 a.m. and 9 a.m. is the optimal time for weight loss.

Researchers from Franklin Pierce University found that individuals who worked out in the early morning displayed a lower BMI and waist circumference. Interestingly, this group was the most sedentary among the morning, mid-day, and evening exercisers.

“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,” says Rebecca Krukowski, PhD, a clinical psychologist with expertise in behavioral weight management, in a media release.

“Our findings propose that the diurnal pattern of moderate to vigorous physical activity could be another important dimension to describe the complexity of human movement,” adds Tongyu Ma, PhD, an assistant professor in the Health Sciences Department at Franklin Pierce University.

“Our study provided a novel tool to explore the diurnal pattern of physical activity and to investigate its impact on health outcomes.”

Historically, most research focused on the frequency, intensity, and duration of physical activity. Few have considered how the timing of exercise might influence its outcomes. It was also previously uncertain if achieving the recommended 150 minutes of moderate to vigorous activity weekly had the same obesity-reducing effect regardless of when it was performed.

Woman jogging on a sunny day
Woman jogging on a sunny day (Photo by Andrew Tanglao on Unsplash)

To address this, the researchers analyzed data from 5,285 individuals from the 2003-2006 cycles of the National Health and Nutrition Examination Survey by the Centers for Disease Control and Prevention. For the purposes of this study, published in the journal Obesity, participants’ daily activity was segmented into morning, mid-day, and evening categories.

Morning exercisers not only had lower BMI and waist circumferences but also reported healthier diets and consumed fewer calories relative to body weight than other groups. Intriguingly, the morning group recorded more sedentary time, yet their superior health metrics persisted.

Demographically, the morning exercisers were on average 10 to 13 years older than participants in the other two groups. This group also contained a higher percentage of women and was predominantly non-Hispanic White. Most had a college degree or higher, and a significant majority had never used tobacco or alcohol.

“It is not known whether people who exercise consistently in the morning may be systematically different from those who exercise at other times, in ways that were not measured in this study,” says Krukowski.

“For example, people who exercise regularly in the morning could have more predictable schedules, such as being less likely to be shift workers or less likely to have caregiving responsibilities that impede morning exercise,” Krukowski continues.

“Predictable schedules could have other advantageous effects on weight that were not measured in this study, such as with sleep length/quality and stress levels. In addition, the ‘morning larks’ who consistently rise early enough for morning exercise may be biologically different from their ‘night owl’ counterparts.”

Prof. Krukowski, co-director of the Community-Based Health Equity center, University of Virginia, School of Medicine, Department of Public Health Sciences, did not take part in the research.

South West News Service writer Jim Leffman contributed to this report.

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