Now think about this for a minute. We're not even talking about aerobic fitness as measured by VO2max or METs. Sure, a chair stand is a semi-squat and grip strength is well, strength. But hey, we didn't even assess push ups, pull ups or even plank time. So we're not even talking about "truly fit" but rather just enough to perform one's activities of daily living.
Of course, due to the nature of this (observational) study, we can't prove whether lack of physical performance caused dementia or whether dementia caused loss of physical performance. Perhaps the two are unrelated? Doubtful, especially in light of yesterday's post regarding mid-life fitness' link to dementia later on in life . So the bottom line hasn't changed: don't just sit there, do something!