The joy of running. That sense of well-being, freedom and extra energy that runners often experience is not just a matter of endorphins. A study at the University of Montreal Hospital Research Centre (CRCHUM) shows that the “runner’s high” phenomenon is also caused by dopamine, an important neurotransmitter for motivation.
“We discovered that the rewarding effects of endurance activity are modulated by leptin, a key hormone in metabolism. Leptin inhibits physical activity through dopamine neurons in the brain,” said Stephanie Fulton, a researcher at the CRCHUM and lead author of an article published in the journal Cell Metabolism.
Secreted by adipose tissue, leptin helps control the feeling of satiety. This hormone also influences physical activity. “The more fat there is, the more leptin there is and and the less we feel like eating. Our findings now show that this hormone also plays a vital role in motivation to run, which may be related to searching for food,” explained Stephanie Fulton, who is also a professor at Université de Montréal’s Department of Nutrition.
Hormone signals that modulate feeding and exercise are in fact believed to be closely linked. Endurance running capacity in mammals, particularly humans, is thought to have evolved to maximize the chances of finding food. This study suggests that leptin plays a critical role both in regulating energy balance and encouraging behaviours that are “rewarding” for the person’s metabolism, i.e., engaging in physical activity to find food.
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