Calorie-cutting mice still exercise, challenging exercise-energy belief

A recent study from the University of California, Riverside, challenges the notion that calorie restriction diminishes exercise motivation in mice. Researchers found that reducing calorie intake by 20% did not significantly affect the distance that mice voluntarily ran each day. The study, published in the journal Physiology & Behavior, involved tracking the running activity of both regular and "high runner" mice over three weeks, with subsequent weeks of calorie reductions. While high runner mice showed a slight decrease in running distance with a 40% calorie reduction, regular mice maintained their running levels. The study suggests that the self-rewarding nature of exercise, linked to increased dopamine and cannabinoid levels, may drive continued activity despite reduced food intake. Interestingly, body mass changes were minimal, with only a slight drop observed at the 40% calorie reduction level. The findings imply that exercise motivation may not be as closely tied to energy availability as previously thought, which could have implications for both wildlife conservation and human health. Future research aims to explore the mechanisms behind the resilience of exercise levels and body mass in response to calorie restriction.

- Calorie restriction does not significantly reduce voluntary exercise in mice.

- Mice maintained high levels of running even with a 40% reduction in calories.

- The study suggests exercise may be driven by self-rewarding mechanisms rather than energy availability.

- Minimal changes in body mass were observed despite calorie reductions.

- Findings could inform strategies for wildlife conservation and human health management.