Your calf muscles may be doing more than helping you walk. They could be talking to your brain through a protein that may influence mood and trigger the growth of new neurons

Scientists identified apelin, a protein signaling from leg muscles to the brain. Exercising mice showed increased apelin levels in their bloodstream and hippocampus. This protein appears crucial for exercise-induced behavioral improvements in mice. Apelin may influence mood by affecting new neuron growth in the brain. Further research is needed to confirm these findings in humans.