Margen
Exercise releases BDNF, a protein that works like fertilizer for your neurons: it helps them survive, connect with one another, and helps new ones be born, especially in the hippocampus, the region key to memory.
That's why moving doesn't just change the body. In a trial with older adults, a year of moderate aerobic exercise (walking at a brisk pace three times a week) increased hippocampal volume by around 2%, effectively reversing one or two years of the shrinkage that comes with age.
You don't need to run marathons: the effect shows up with steady, achievable aerobic exercise. If you have to study something hard or you've been stuck on a problem for hours, take a brisk half-hour walk beforehand. Moving your body is also a way of studying.
Source: Erickson et al., PNAS (2011), University of Pittsburgh