Unlock Your Ultimate Weight Loss Potential: Discover the Perfect Time to Exercise

Join CNNs Fitness, But Better newsletter series to receive our comprehensive seven-part guide. With expert backing, this guide will assist you in gradually adopting a healthy routine.

For individuals aiming for weight loss, it is advisable to carefully choose the time of day for exercising. Recent research provides valuable insights that can optimize your fitness endeavors.

A study published Tuesday in the journal Obesity found that exercising between 7 a.m. and 9 a.m. is linked to a lower waist circumference and body mass index compared to those who work out later in the day. Rebecca Krukowski, a clinical psychologist specializing in behavioral weight management, commented in a news release that this new research supports the recommendation to schedule exercise in the morning to avoid distractions from emails, phone calls, or meetings.

Beautiful woman running in city street.

Rossella De Berti/E+/Getty Images

Rucking is an easy way to fitness

Previous researchers have reported positive connections between moderate-to-vigorous physical activity and weight loss. However, there is inconsistent evidence on the optimal time to exercise for losing weight. Therefore, the authors of the latest study investigated the impact of exercising at different times on the relationship between physical activity and obesity. To conduct their research, the authors analyzed health and activity data from 5,285 individuals who participated in the US Center for Disease Control and Prevention's National Health and Nutrition Examination Survey during the 2003 to 2006 cycles. These specific years were selected because they marked the initial use of accelerometers, or activity trackers, in the survey.

After recording their BMI and waist circumference, participants were instructed to wear activity trackers on their right hip for at least 10 hours a day for a period of four to seven days.

The findings indicated that individuals who exercised in the morning, specifically between 7 a.m. and 9 a.m., had an average BMI of 27.5. Comparatively, those who exercised during midday (9 a.m. to 4 p.m.) and evening (5 p.m. to 8 p.m.) had an average BMI of 28.3.

When accounting for factors such as diet quality and calorie intake, the average waist circumference for the three groups was determined to be 96 centimeters (37.7 inches), 97.8 centimeters (38.5 inches), and 97.5 centimeters (38.4 inches), respectively.

READ MORE: Optimal timing for fueling your workouts

These findings remained consistent regardless of gender, race, level of education, tobacco or alcohol habits, or sedentary lifestyle. Moreover, even individuals who successfully met the recommended physical activity guidelines by engaging in at least 150 minutes of exercise per week, experienced the lowest BMI and waist circumference when they exercised in the morning.

"This research provides valuable evidence, based on a national sample of US participants, which has not been previously explored in relation to the timing of exercise and weight loss," stated Dr. Tongyu Ma, the lead author of the study and a research assistant professor of rehabilitation sciences at the Hong Kong Polytechnic University, via email. However, the participants' BMI and waist size were only measured prior to the activity tracking period, and there was no subsequent measurement taken, making it impossible for the authors to directly establish a causal relationship between exercising in the morning and its impact on these measurements."

Ma said he intends to conduct further studies to validate the results and determine if there is a direct link between morning exercise and a reduced BMI and waist size. The significance of the timing will be assessed.

Experts attributed the underlying causes of these findings to factors related to both physiology and lifestyle habits.

Due to the limitations of the study design, it remains uncertain whether individuals who consistently exercise in the morning may possess distinct characteristics, not accounted for in this study, compared to those who exercise at different times. Krukowski, a professor of public health sciences and co-director of the Community-Based Health Equity Center at the University of Virginias School of Medicine, highlighted this ambiguity.

Siam Pukkato/Adobe Stock

According to a study, walking for just 2 minutes after a meal can improve blood sugar levels. Additionally, the research suggests that individuals who engage in regular morning exercise may have more consistent schedules and fewer responsibilities that may hinder their ability to exercise in the morning. These predictable schedules could potentially have other positive impacts on weight management, including sleep quality, duration, and stress levels.

Experts have suggested that morning people may have biological differences compared to night owls. Previous studies have shown that individuals who exercise in the morning tend to consume fewer calories throughout the day and passively burn more energy when they're not exercising. This may seem contradictory, but it is likely because working out in a fasted state in the morning forces the body to use stored fat for energy instead of stored glucose from food. As a result, early birds may have bodies that are more efficient in increasing fat burning both during exercise and throughout the day, even when they are inactive after their workout.

In the latest study, morning exercisers were the most sedentary even though they had the lowest BMI and waist circumference.

(add caption)

Boris Jovanovic/iStockphoto/Getty Images

According to experts, engaging in fascia training can assist in reducing pain levels and improving overall well-being. "Personally, I find this concept appealing as it assures me that by dedicating my mornings to exercise, I can comfortably concentrate on work throughout the day without being concerned about gaining weight," Ma shared in an email.

The authors also noted that a more focused or organized exercise can lead to a greater weight loss. They found this to be true among individuals who exercised in the morning. Additionally, "early morning aerobic exercise, such as biking, running, or brisk walking, is a promising method for weight loss," stated Ma. He also mentioned that most people are more inclined to adhere to a workout routine in the morning compared to midday or evening.