Brain chemical decides whether to snack or exercise or how do we get to temptation-resistant voluntary exercise

Good news! Towards a better understanding of obesity! It is not dopamine!

"... The chemical orexin, which also mediates sleep, prompted mice to choose exercise over a snack more frequently. ...

“Our brain releases dopamine both when we eat and when we exercise, which does not explain why we choose one over the other.” ...

About 1 in 2,000 people have genetic conditions that restrict their orexin systems, which causes the sleeping disorder narcolepsy. Conversely, some people with insomnia are prescribed drugs that block orexin. Both of these populations may be helpful for studying the effect in people."

"In brief

• The chemical messenger orexin and the orexin neurons in the brain mediate the decision between exercise and snacking. Researchers ... made this discovery in mice. The results are likely to be transferable to humans.
• In the experiment, mice with a blocked orexin system opted more frequently for the milkshake offered them and less for exercise.
• These results could help in researching and developing new strategies to promote physical activity in people.

..."

From the abstract:

"Despite the well-known health benefits of physical activity, many people underexercise; what drives the prioritization of exercise over alternative options is unclear. We developed a task that enabled us to study how mice freely and rapidly alternate between wheel running and other voluntary activities, such as eating palatable food. When multiple alternatives were available, mice chose to spend a substantial amount of time wheel running without any extrinsic reward and maintained this behavior even when palatable food was added as an option. Causal manipulations and correlative analyses of appetitive and consummatory processes revealed this preference for wheel running to be instantiated by hypothalamic hypocretin/orexin neurons (HONs). The effect of HON manipulations on wheel running and eating was strongly context-dependent, being the largest in the scenario where both options were available. Overall, these data suggest that HON activity enables an eat–run arbitration that results in choosing exercise over food."

Brain chemical decides on eating or exercise

Sport or snack? How our brain decides (original news release) "The brain chemical orexin is crucial when we choose between sport and the tasty temptations that beckon everywhere we turn. This research finding could also help people who find it difficult to motivate themselves to exercise."

Orexin neurons mediate temptation-resistant voluntary exercise (open access)

Fig. 1: TRVE [temptation-resistant voluntary exercise] in mice.