The cause of Alzheimer's disease is unknown, but various studies suggest that its risk factors extend beyond genetics. Some studies have associated the disease with a dearth of physical activity. Others have linked Alzheimer's disease to a lack of stimulating brainwork–fitting a use-it-or-lose-it scenario of cognitive decline.
A new study bolsters the view that both kinds of inactivity pose risks. People who have the memory loss, confusion, and disorientation of Alzheimer's disease in old age were generally less active physically and intellectually between the ages of 20 and 60 than were people who don't have the disease, according to study coauthor Robert P. Friedland, a neurologist at Case Western Reserve University School of Medicine in Cleveland, and his colleagues.