‘Highly fit’ middle-age women are nearly 90% less likely to develop dementia decades later, a new study finds. Researchers gave participants an initial exercise test in middle age then followed them for 44 years. Those who could ride an exercise bike at a fast rate for 6 minutes in the initial test had a much lower risk of dementia later on than those who couldn’t complete the workout. The study was published Wednesday in the journal ‘Neurology.’ Ref. USAToday.