Aerobic + Strength Exercise Doesn't Slow Cognitive Decline

Henrietta Brewer
May 17, 2018

The Alzheimer's Society commented on the link, also suggesting that there are a range of lifestyle factors that could affect our dementia risk. "We had hoped to see improvements in behavior and function in activities of daily living, but these did not occur either". But recent reviews of trials of exercise training in people with dementia have shown conflicting results.

Researchers took a look at 6,220 British people over the age of 65, and found that those with fewer financial resources when they were older were more likely to develop dementia. "We also used completely independent healthcare professionals to measure the outcome using a sensitive and well-recognized test of cognition".

The participating individuals who had taken part in an exercise programme were even found to have had slightly worse scores in an Alzheimer's assessment when they were tested a year later.

The exercise programme consisted of group sessions of 60 to 90 minutes in a gym twice a week for four months, plus home exercises for one additional hour each week with ongoing support.

ADAS-cog results run on a scale from 0 to 70, with higher scores suggesting greater impairment.

There was no difference between the groups in terms of behaviour, quality of life, ability to carry out everyday tasks or numbers of falls (which can be a cause of injury in people with dementia).

The study found that the connection could be made regardless of the level of schooling people had received, and other health indicators.

Although a short-term improvement in physical fitness was reported among patients in the exercise group, cognitive impairment after 12 months had declined a similar amount in both groups. In fact, the decline was steeper in the exercise group, although, as the researchers point out in their paper, the average difference between the two groups was small and the "clinical relevance was uncertain". Activities of daily living, number of falls, and quality of life were also assessed.

"Is 4 months enough?" asked Ronald Petersen, MD, of the Mayo Clinic in Rochester, Minn., and lead author of the American Academy of Neurology (AAN) practice guideline for mild cognitive impairment (MCI), which recently recommended exercise for patients with MCI. "It may take a longer intervention to have an effect".

The study has several important limitations. The structured exercise period might have been too short, although changes in physical fitness occurred during the trial and did not transfer into other clinically meaningful benefits.

Regarding the question of whether exercise might worsen dementia, they noted that those who did the most exercise had worse outcomes, saying it was "possible" the programme may have worsened mental abilities.

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