Research Highlights Morning Workouts’ Impact on Waist Circumference and BMI
In the pursuit of effective weight loss strategies, the timing of your exercise routine may be the key to success, according to a groundbreaking study published in the journal Obesity. The research, involving a significant sample of 5,285 participants, discovered that individuals who engage in physical activity between 7 a.m. and 9 a.m. experience more substantial weight loss, as measured by their waist circumference and body mass index (BMI), compared to those exercising during midday or evening.
Clinical psychologist Rebecca Krukowski, a specialist in behavioral weight management, commented on the study’s significance, emphasizing the importance of scheduling exercise in the morning to minimize distractions from emails, phone calls, or meetings that can derail fitness goals.
While prior research has identified a connection between moderate-to-vigorous physical activity and weight loss, determining the most effective time for exercise has yielded mixed results. To address this gap, the researchers examined data from participants in the 2003 to 2006 cycles of the US Center for Disease Control and Prevention’s National Health and Nutrition Examination Survey.
Participants wore activity trackers for extended periods during the day and had their BMI and waist circumference recorded. The study found that those who exercised in the morning, between 7 a.m. and 9 a.m., boasted an average BMI of 27.5, while midday and evening exercisers had an average BMI of 28.3. This difference was consistent even when accounting for factors like diet quality, calorie intake, sex, ethnicity, education, tobacco use, alcohol consumption, or sedentary behavior.
Remarkably, the benefits of morning exercise remained significant among individuals who met the recommended 150 minutes of physical activity per week. The research demonstrated that morning exercise is linked to the lowest BMI and waist size.
However, the study did not measure BMI and waist size after the activity tracking period, making it challenging to establish a direct causal relationship between morning exercise and the observed reductions in these measurements. The lead author, Dr. Tongyu Ma, plans to conduct further studies to confirm these findings and explore potential causal connections.
The factors driving these findings may stem from both physiology and lifestyle habits. People who consistently exercise in the morning may have more predictable schedules, which could have additional positive effects on weight related to sleep quality and stress levels. Additionally, morning exercisers appear to have a lower daily caloric intake and higher passive energy expenditure, likely due to exercising in a fasted state.
Notably, the study found that morning exercisers had the lowest BMI and waist circumference, even though they were the most sedentary post-exercise. This suggests that morning workouts may set the stage for enhanced fat oxidation, potentially contributing to greater weight loss throughout the day.
Furthermore, the study observed that morning exercisers tended to adopt more structured and concentrated exercise routines, contributing to their superior weight loss results. Dr. Tongyu Ma emphasized that early morning aerobic exercises like biking, running, or brisk walking show promise as effective tools for weight loss, as people are generally more likely to adhere to a morning workout routine.