A recent animal study suggests that intense exercise may unexpectedly contribute to weight gain by reducing subsequent physical activity and lowering body temperature. This effect may be linked to disruptions in the circadian rhythm of the stress hormone corticosterone, which influences physical activity and body temperature. The findings highlight the impact on overall activity levels and hormonal rhythms when designing weight-loss programs. Regular physical activity plays an essential role in maintaining physical and mental well-being and is frequently recommended as an effective strategy for weight loss, whether individuals opt for light activities like walking or more intense exercises such as uphill cycling or weight lifting. Engaging in daily exercise of any intensity is vital for preventing various diseases and health problems. However, a recent mouse study suggests that intense exercise sessions may lead to reduced subsequent physical activity and lower body temperature, which may contribute to weight gain.
The researchers evaluated how the circadian rhythm, the body’s natural sleep and wake cycle, played a role in activity by examining the stress hormone corticosterone, which regulates the circadian rhythm. While exercise has numerous health benefits, its impact on weight loss can sometimes be less than anticipated, possibly due to a decrease in physical activity following exercise, though the exact mechanism remains unclear. Corticosterone, which follows a circadian rhythm, regulates both physical and mental activity levels. The study hypothesized that even a single session of high-intensity exercise could disrupt this rhythm, leading to decreased physical activity, lower heat production, and diminished weight loss effects. The researchers monitored physical activity and core body temperature before and after exercise in mice divided into high-intensity exercise, moderate-intensity exercise, and rest groups, noting a disruption in the synchrony between physical activity and body temperature.
Lead researcher Takashi Matsui, PhD, explained that a single session of high-intensity exercise can disrupt corticosterone’s circadian rhythm, leading to decreased physical activity, lower body temperature, and weight gain. Matsui emphasized the importance of considering not just the calories burned during exercise but also the subsequent activity levels and circadian rhythm when designing exercise regimens for effective weight loss. The study findings suggest that vigorous exercise may have complex effects on metabolism that are not fully understood, potentially leading to reduced activity levels outside of exercise sessions and impacting body temperature regulation, ultimately counteracting weight loss efforts if not managed properly. Matsui added that the research supports the theory that animals, including humans, tend to compensate for the energy expenditure of exercise by reducing energy use in other activities. Glatt, a senior brain health coach, recommended rethinking the focus on intense exercise for weight loss and considering the potential benefits of moderate and consistent activity instead.
Mark A. Anton, MD, described the study as fascinating and highlighted the importance of recognizing the potential impacts of vigorous exercise on activity levels and body temperature regulation. He recommended a balanced approach that includes a mix of moderate-intensity aerobic exercises and resistance training for weight loss and weight management. It is crucial to incorporate rest and recovery to prevent burnout and ensure sustainable progress. Matsui emphasized the importance of engaging in moderate exercise regularly to sustain the benefits without inadvertently leading to weight gain. The research suggests that a balanced approach to exercise, including both moderate and intense activities, may be more beneficial for weight loss and overall health. However, it is essential to consider individual factors and preferences when designing exercise regimens to ensure long-term success.
