Intense exercise reduces activity and body temperature, promoting weight gain
Last reviewed: 14.06.2024
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Exercise is often recommended as an effective strategy for losing weight. However, a recent animal study conducted at the University of Tsukuba found that intense exercise may reduce subsequent physical activity and body temperature, which may ultimately promote weight gain. This observation may be related to disturbances in the circadian rhythm of the stress hormone corticosterone and may disrupt the synchronous effects of physical activity and body temperature.
Exercise has many health benefits, but its impact on weight loss is sometimes less than expected. This phenomenon may be secondary to a decrease in physical activity after exercise, but the mechanism is not yet fully understood.
The stress hormone corticosterone follows a circadian rhythm, being low before sleep and peaking upon awakening, and it regulates levels of physical and mental activity. Therefore, the researchers hypothesized that even one session of high-intensity exercise could disrupt this rhythm, leading to decreased physical activity and heat output and reducing the weight-loss effect.
To test this hypothesis, mice were divided into three groups: high-intensity exercise, moderate-intensity exercise, and rest. Physical activity and body temperature, which serve as an indicator of heat production, were monitored before and after exercise. The study was published in Medicine & Science in Sports & Exercise.
In the high-intensity exercise group, both physical activity and body temperature decreased significantly after exercise, despite no change in food intake, resulting in weight gain.
Moreover, the researchers observed a disruption in the synchrony between physical activity and body temperature. Together, they confirmed the positive correlation that relatively low blood corticosterone levels during wakefulness were associated with less physical activity.
The findings suggest that a single bout of high-intensity exercise can disrupt the circadian rhythm of corticosterone, leading to decreased physical activity, decreased body temperature, and weight gain.
This study highlights the importance of considering not only the calories burned during exercise, but also subsequent activity level and circadian rhythm when designing exercise programs for effective weight loss.