A new study from ETH Zurich has uncovered the brain mechanism behind our choices to exercise or indulge in tempting snacks. The research, published in Nature Neuroscience, points to a chemical messenger called orexin as the key player in this decision-making process.
Orexin: The Brain’s Exercise Motivator
Scientists have long puzzled over why some people consistently choose exercise over tempting alternatives. This study provides compelling evidence that orexin, a brain chemical discovered just 25 years ago, plays a crucial role.
In experiments with mice, researchers found that animals with a functioning orexin system spent twice as much time exercising and half as much time consuming a milkshake compared to mice whose orexin system was blocked. Importantly, this difference only appeared when both options were available simultaneously.
“Our results suggest that orexin is central to making the decision between exercise and eating when both choices are present,” explains Professor Denis Burdakov, who led the study. “Without orexin, the decision strongly favored the milkshake, and the mice gave up exercising in favor of eating.”
Implications for Human Health
While the study was conducted in mice, the brain functions involved are believed to be nearly identical in humans. This discovery could have significant implications for addressing the global obesity epidemic and related health issues.
Dr. Daria Peleg-Raibstein, co-leader of the study, notes, “If we understand how the brain arbitrates between food consumption and physical activity, we can develop more effective strategies for addressing obesity and metabolic disorders.”
The findings may be particularly relevant given current exercise trends. The World Health Organization reports that 80% of adolescents and 27% of adults don’t get enough physical activity.
Why it matters: This research provides a potential neurological explanation for why some people struggle to choose exercise over less healthy alternatives. Understanding this brain mechanism could lead to new approaches for promoting physical activity and combating obesity.
The team now plans to verify their results in humans. This could involve studying patients with genetic conditions affecting their orexin system or observing individuals taking orexin-blocking medications for insomnia.
As research progresses, these findings may open new avenues for developing interventions to help people overcome exercise barriers. However, the path from lab discovery to practical applications will require extensive further study.
Professor Burdakov and his team are continuing their basic neuroscience research, focusing next on how orexin neurons interact with other parts of the brain during decision-making processes like choosing between exercise and snacking.
