Uh oh ... Physical Exerice Actually Worsens Dementia?

This week, a team of British medical researchers published a report of their research that found "a moderate to high intensity aerobic and strength exercise training programme does not slow cognitive impairment in people with mild to moderate dementia."  In fact, physical exercise may have worsened cognitive impairment in some subjects.  The authors speculated that reoxygenation of cortical areas may have been slowed.  Inflammation induced by higher levels of exercise might also be implicated.  The research was published in theBMJ, which is a top-tier medical journal.

So what does this mean?  Does it contradict all of the existing research that associates physical exercise with improved cognition -- a premise of Beating the Dementia Monster?

No, it doesn't.  Quoting Dr Elizabeth Coulthard, Consultant Senior Lecturer in Dementia Neurology at the University of Bristol, the London Telegraph notes that these results are relevant to people with mild to moderate dementia, but they are not relevant to people with mild cognitive impairment.  People with MCI have cognitive challenges, but they have not advanced to dementia.

What occurs to me here is that once someone has advanced to true dementia, brain function may have deteriorated in a manner that reoxygenation of cortical areas is impaired.  If so, this would explain why physical exercise may contribute to deterioration of cognition in people with even mild dementia, even though it actually improves cognitive function in people with MCI.

As noted in my April 30 post, the medical community has redefined the term "Alzheimer's disease" and differentiated Alzheimer's disease and Alzheimer's dementia.  Alzheimer's disease may begin years or a decade before symptoms of cognitive impairment appear.  Alzheimer's dementia appears much later.  A person is considered to have advanced from mild cognitive impairment to dementia when the disease begins to interfere with daily activities.