Vigorous Exercise Linked to Reduced Non-Exercise Activity and Weight Gain, reveals study

Exercise is well-known for its numerous health benefits, including improved cardiovascular health, enhanced mental well-being, and increased longevity. However, its effectiveness for weight loss is often overestimated. One proposed explanation for this is the compensatory decrease in NEPA, which reduces non-exercise activity thermogenesis (NEAT), potentially offsetting the calories burned during exercise. Despite this theory, the specific mechanisms and the impact of different exercise intensities have not been fully understood.

In this study, adult male C57BL/6 J mice were divided into three groups: sedentary, moderate exercise, and vigorous exercise. The exercise groups underwent a 30-minute treadmill session. Researchers used intraperitoneally implanted activity monitors to track NEPA and BT for two days before and three days after the exercise session. The synchrony between NEPA and BT was assessed using a cross-correlation function. Plasma corticosterone levels were measured 6 and 24 hours post-exercise to evaluate stress response and its correlation with changes in NEPA.

• The study revealed that only the vigorous exercise group exhibited a significant decline in both NEPA and BT the day after exercise.

• This reduction was associated with weight gain despite no changes in food intake. Specifically, the vigorous exercise group showed:

• A decrease in NEPA and BT, leading to weight gain the following day.

• A delay in the daily dynamics of NEPA compared to BT, suggesting a disruption in their synchrony.

• A positive correlation between plasma corticosterone levels and changes in NEPA levels before and after exercise, indicating a stress response influencing NEPA.

• The moderate exercise group did not show these declines, highlighting the unique impact of exercise intensity.

The findings suggest that vigorous exercise may inadvertently lead to weight gain due to reduced NEPA and altered BT, potentially mediated by disruptions in circadian rhythms and increased corticosterone levels. This underscores the importance of considering exercise intensity and its broader physiological effects beyond immediate calorie expenditure.

These findings have significant implications for exercise prescriptions aimed at weight loss. While vigorous exercise has many health benefits, it may not be the best strategy for weight loss due to its impact on NEPA and BT. Future research should explore strategies to mitigate these effects, potentially incorporating moderate exercise or mixed-intensity routines to maximize benefits without adverse outcomes.

The study concludes that vigorous exercise can lead to reduced non-exercise activity, decreased body temperature, and subsequent weight gain, likely due to disrupted circadian rhythms of corticosterone. This highlights the need for a nuanced approach to exercise regimens, considering both intensity and the broader physiological impacts to optimize health benefits.

Reference:

Funabashi, D., Dobashi, S., Sameshima, K., Sagayama, H., Nishijima, T., & Matsui, T. (2024). Acute vigorous exercise decreases subsequent non-exercise physical activity and body temperature linked to weight gain. Medicine and Science in Sports and Exercise, 10.1249/MSS.0000000000003487. https://doi.org/10.1249/mss.0000000000003487