Watching a lot of TV and having a low physical activity level as a young adult were associated with worse cognitive function 25 years later in midlife, according to an article published online by JAMA Psychiatry.Few studies have investigated the association between physical activity in early adulthood and cognitive function later in life. Coupled with the increasing prevalence of sedentary or screen-based activities, such as watching television, these trends are of concern for upcoming generations of young people.