What is the best time for workouts to be most effective for weight loss?

Rsearchers have uncovered a key insight into the optimal timing for engaging in moderate to vigorous physical activity to enhance weight management and improve health outcomes, particularly in relation to obesity.

The study, led by Tongyu Ma, an assistant professor at Franklin Pierce University and The Hong Kong Polytechnic University, challenges previous research that focused on the frequency and intensity of physical activity. Instead, it delves into the diurnal pattern of physical activity to determine when during the day such activity is most beneficial.

Traditionally, research in this field has concentrated on the duration of physical activity, but this study breaks new ground by examining the timing of physical activity and its potential effects on obesity. It also investigates whether meeting the recommended physical activity guidelines of 150 minutes per week, but with different time patterns, has an equal impact on reducing obesity.

The findings, published in Obesity, resuggest that the hours between 7 a.m. and 9 a.m. may be the most opportune time for individuals looking to maximise their weight management efforts through moderate to vigorous physical activity.

To conduct this research, the team analysed data from the 2003–2004 and 2005–2006 cycles of the National Health and Nutrition Examination Survey by the Centers for Disease Control and Prevention. They classified the diurnal pattern of objectively measured moderate to vigorous physical activity into three categories: morning, mid-day, and evening, using the K-means clustering analysis technique.

The results revealed a strong linear connection between morning physical activity and obesity reduction, whereas a weaker, curvilinear association was observed in the midday and evening groups. Participants who met the physical activity guidelines in the morning group displayed a lower body mass index and waist circumference, indicating better weight management. They also reported healthier dietary habits and less daily energy intake per unit of body weight.

Surprisingly, despite spending more time in sedentary behavior, participants in the morning cluster consistently maintained their lower body mass index and waist circumference. This suggests that morning exercise may have unique benefits, even in the face of extended periods of sitting.

Furthermore, participants in the morning group tended to be older and primarily non-Hispanic White, with higher levels of education and lower tobacco and alcohol usage. These demographic factors may play a role in their ability to exercise consistently in the morning.

Rebecca Krukowski, a clinical psychologist with expertise in behavioral weight management, commented on the study’s significance. She noted that scheduling exercise in the morning, before distractions like emails and meetings, aligns with this new research.

However, Krukowski emphasised that since this is a cross-sectional study, it cannot definitively prove causation. Other factors, such as predictable schedules, sleep quality, and biological differences, may also contribute to the observed results.