Data from a publicly available database of 1206 MRI brain scans from the Human Connectome Project has revealed that physical fitness is associated with better brain structure and brain functioning in young adults.

A study in which 64 sedentary older adults (aged 60-88) participated in a 12-week exercise program found that those who engaged in high-intensity interval training (HIIT) saw an improvement of up to 30% in memory performance while participants who engaged in moderate-intensity aerobic exercise s

A small study involving 12 very fit older adults (aged 50-80; average age 61) found that, after stopping their exercise routines for 10 days, there was a significant decrease in blood flow to several brain regions, including the

A study involving 30 previously physically inactive older adults (aged 61-88) found that a three-month exercise program reversed some brain atrophy.

A long-running study following 387 Australian women found that regular exercise in middle age was the best lifestyle change they could make to prevent cognitive decline in their later years.

A Canadian study involving 45,522 adults (30+) found that higher levels of physical activity, eating more fruits and vegetables, and having a BMI in the normal weight or overweight range were each associated with better cognitive function in both younger and older adults.

A rat study comparing different forms of exercise has found that running was much more effective than HIIT or resistence training in generating new brain cells.

A large study, involving nearly 14,000 older adults (50+) participating in the 2006 Health and Retirement Study, found that weaker handgrip strength was associated with a greater risk of developing cognitive impairment, especially severe impairment, over the eight-year study period.