Questionnaire-based studies on physical activity and dementia risk show no association, unlike studies that objectively measure VO2 max.

“you'll find questionnaire studies that also show you know a benefit like you know people that are physically fit and the more fit they are there's like a linear dose response effect right where you see you know people that put in more effort they're training for a longer period of time and they're um you know doing it more vigorate more vigorous or more volume both right like they have the greatest benefit with respect to dementia risk which isn't so surprising to me yeah but this the studies that are unambiguous as you said are the ones that actually measure VO2 max”