Exercise has health benefits at all ages! From Medical Xpress:
Study indicates exercise sharpens the young adult brain
Regular physical activity improves brain function even in young adults considered in their prime and at the height of cognitive ability, according to a new University of Otago study.
They took 52 tertiary students, aged from 18 to 30, and put them through a series of cognitive tests on a computer while measuring oxygen availability in the frontal lobe of their brains, as well as their self-reported exercise frequency. Dr Machado says their "surprising" findings, just published online in the journal Psychophysiology, show that both blood supply to the brain and cognitive functioning appear to benefit from regular exercise in young adults.
"This provides compelling evidence that regular exercise, at least 5 days per week, is a way to sharpen our cognitive ability as young adults – challenging the assumption that living a sedentary lifestyle leads to problems only later in life," she says... "The exercise could involve brisk walking or more vigorous activity, and could be made up of a few 10 minute bouts of exercise, rather than one single block of exercise," she says.
The researchers also found that body mass index was not a key factor in how well the brain functioned, indicating that regular engagement in physical activity may be more important than body weight.