Weekly physical and mental exercises for a year helped improve the symptoms of Parkinson's disease patients, who showed improvements in one-minute sit-to-stand tests and MiniMental cognitive tests.

An 18-year study of 1 million women found that midlife obesity, but not poor diet or lack of exercise, was linked to a 21% increase in risk of dementia, compared to normal BMI women.

Engaging in culture, including museums, art, or theater, was linked to longer life in older adults during a 12-year study. Even engaging once or twice yearly led to a 14% reduction in mortality.

Having more body fat and less muscle as we age leads to less flexible thinking, possibly due to immune system changes. People with a higher BMI have more immune system activity, which affect cognition.