New Research: Exercising at This Hour of Day Helps You Lose the Most Weight

Updated: Oct. 12, 2023

New research uncovers fascinating new science showing how even if you sit all day, exercising at this time might yield the trimmest result.

Just as winter draws near, new research might have just delivered the motivation you need to start those chilly days with some movement. A September 2023 study published in the peer-reviewed journal Obesity suggests that the best time to exercise for weight management might be in the early morning, with the researchers even narrowing the science right down to the hour. Their research explores the connection between patterns of physical activity and obesity, offering that the timing of exercise could have a notable impact on health outcomes.

Why morning is the best time to exercise

Tongyu Ma, PhD, assistant professor at The Hong Kong Polytechnic University, and his team discovered something intriguing: Those who get moving early in the morning (between 7 a.m. and 9 a.m.) might have a leg up when it comes to managing their weight.

Their study, which analyzed data from more than 5,000 participants in the Center for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES) from 2003 to 2006, found that individuals who engaged in moderate to vigorous physical activity in the early morning had a lower body mass index and waist circumference.

Not only that, but they also tended to follow a healthier diet and consumed fewer daily calories relative to their body weight.

Dr. Ma and his team suggest that exploring the “diurnal pattern”—the daily frequency—of this type of physical activity could offer a new way to understand the impact of regular movement on human health.

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The intricacies of movement

The study didn’t just highlight the potential benefits of a morning workout, and why it might be the best time to exercise—it also explored the complex relationship between daily movement patterns and obesity. Even though participants in the morning exercise group spent more time being sedentary, they still maintained lower body mass index and waist circumference, revealing a fascinating paradox that warrants further exploration.

The early exercisers were generally older (by 10 to 13 years) than their counterparts in other groups and were predominantly non-Hispanic White females with at least a college education. Interestingly, they were also likely never to have used tobacco or alcohol.

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Expert insights

Rebecca Krukowski, PhD, a clinical psychologist specializing in behavioral weight management from the University of Virginia School of Medicine (who was not involved in the study), finds the research exciting and consistent with the standard advice that the best time to exercise is in the morning to help you avoid distractions.

However, Dr. Krukowski also emphasizes a crucial point: The study tells us about an association between time of day for exercise and weight management, but it doesn’t tell us about causality. Dr. Krukowski notes in a news release, “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.”

In other words, it’s possible those who exercise first thing in the morning tend to follow that same type of discipline throughout their day, which can influences diet habits.

Also, unmeasured factors like sleep quality and stress levels—which play into metabolic health—might have significant roles in weight management and need to be studied further.

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