Regular exercise may help improve mental function

A study reported in The Lancet shows that

Leisure-time physical activity at midlife is associated with a decreased risk of dementia and AD [Alzheimers Disease] later in life. Regular physical activity may reduce the risk or delay the onset of dementia and AD, especially among genetically susceptible individuals.
The study has followed 1449 individuals over a period of time from 1972 to 1998. This allowed researchers to check on earlier exercise habits of those who later developed dementia or Alzheimers Disease.

The study controlled for age, sex, education, follow-up time, locomotor disorders, genetic pre-disposition, vascular disorders, smoking, and alcohol drinking, finding that exercise was associated with a lower risk of dementia and AD independent of these factors.

Most common types of exercise reported by participants in the study were walking and bicycling.