This is bad news for people like me, who due to arthritis are limited in mobility. It is also a problem for disabled people in wheel chairs. Adults over 60 years who spend a lot of time in sedentary activities such as sitting, appear to be at increased risk of developing dementia. The time spent is about 10 hours a day. While that seems a lot, the average time spent sitting for Americans is 9.5 hours, so clocking up 10 hours is not so difficult seeing that much work today requires sitting at desks. These people are too exhausted to do much after work, and slump in front of the TV.
It truly is a recipe not only for mental deterioration, but general ill health. One must try and break the cycle as best one can if affected. I try to do regular walks, even if I have to use my walking frame to do it. On good days I can get by with just my cane.