Activities that maintain cardio fitness - such as running, swimming and cycling lead to better thinking skills and memory 20 years on, according to researchers at the University of Minnesota, Minneapolis.
Researchers tested almost 3,000 healthy people with an average age of 25. They underwent treadmill tests of cardiovascular fitness during the first year of the study and again 20 years later.
They were asked to run for as long as possible before they became exhausted or short of breath.
People who ran for longer on the treadmill performed better at tests of memory and thinking skills 25 years on, even after adjusting for factors such as smoking, diabetes and high cholesterol, 'BBC News' reported.
People who had smaller time differences in their treadmill test 20 years later were more likely to perform better on the executive function test than those who had bigger differences.
"This is one more important study that should remind young adults of the brain health benefits of cardio fitness activities such as running, swimming, biking or cardio fitness classes," said study author Dr David Jacobs.