A single bout of intense exercise can reduce physical activity and body temperature, leading to weight gain.

Exercise is often recommended as an effective strategy for weight loss. However, a recent animal study conducted at the University of Tsukuba revealed that an intense exercise session can reduce subsequent physical activity levels and body temperature, ultimately leading to weight gain. This observation may be associated with a disruption of the circadian rhythm of the stress hormone corticosterone, which may interfere with the synchronizing effect of physical activity and body temperature.

Although exercise has many health benefits, it may not result in the weight loss you expect. This may be secondary to reduced physical activity after exercise, but the mechanisms underlying this are not yet fully understood.

The stress hormone corticosterone follows a circadian rhythm – low at bedtime and peaking during awakening – which regulates physical and mental activity levels, so the researchers hypothesized that even a single bout of high-intensity exercise could disrupt this rhythm, reducing physical activity and thermogenesis, potentially reducing weight loss outcomes.

To test this hypothesis, mice were divided into three groups: high-intensity exercise, medium-intensity exercise, and rest, and their physical activity and body temperature (an indicator of heat production) were monitored before and after exercise. Medicine and Science in Sports and Exercise.

In the high-intensity exercise group, both physical activity and core body temperature were significantly reduced after exercise, leading to weight gain, despite no change in food intake.

Additionally, the researchers observed a desynchronization of physical activity and body temperature. Taken together, these findings confirmed a positive correlation between lower circulating corticosterone levels during waking hours and reduced physical activity.

Research shows that a single bout of high-intensity exercise can disrupt circadian corticosterone rhythms, leading to reduced physical activity, reduced body temperature, and weight gain.

This study highlights the importance of considering not only the calories burned during exercise but also activity levels and circadian rhythms afterward when designing an exercise plan for effective weight loss.