Regular exercise reduces activity in the sympathetic nervous system, also known as the 'fight or flight' response in the brain. It can help regulate this response by increasing activity in the parasympathetic nervous system... including lowering blood pressure, regulating breathing, and slowing heart rate.
Spurs the growth of new brain cells as you age
As we get older, the birth of new brain cells slows, and our brain tissue actually shrinks. Exercise may be able to reverse that trend. One brain-scanning study of healthy but sedentary people aged 60 to 79 showed significant increases in brain volume after six months of aerobic fitness training.