Why running gives you that high
A good run can be exhilarating. Sure, there are public sensibilities to be considered when contemplating whether to clad yourself in lycra or skimpy short-shorts and heft your body around the footpaths of your neighbourhood. Despite any social drawbacks though, ask any runner and they will tell you what a buzz they get from their run and now researchers have found that the runner’s high is about more than endorphins or even the thrill of the outdoors.
The study centred around the hormone leptin. The primary purpose of leptin is in regulating energy stores and to that end it signals to the brain when the body has enough fuel and energy, and when that happens you feel satiated, or full. We also know that leptin inhibits physical activity via dopamine neurons in the brain.
Although the runner's high is a complex phenomenon it seems that low leptin levels increase motivation to run and make it easier to get that buzz.
To test how leptin might impact the runner’s high these researchers compared normal mice to mice who had the effect of leptin blocked via a molecule stimulated by leptin called STAT3. The researchers compared how much voluntary wheel running the two groups of mice engaged in. Mice can run up to seven kilometres a day and the researchers found that mice with blocked leptin signalling ran much more. So low leptin levels seem to motivate more running.
According to the researchers when you are in motion, your leptin levels may fall, and this could send a hunger signal to the brain’s pleasure centre to generate the rewarding effects of running.
The evolutionary theory of this goes that mice and humans (in fact all mammals) run to chase down food when food is scarce. So low leptin levels drive the desire to run and the satisfaction you get from running. This fits with previous research showing a correlation between marathon run times and leptin levels.
Although the runner’s high is a complex phenomenon it seems that low leptin levels increase motivation to run and make it easier to get that buzz.
No wonder you get hungry for a run.
