Contrary to several previous studies, new research has suggested that a common form of exercise does not improve cognitive impairment among people with dementia.
The research, published in the British Medical Journal (BMJ), found moderate to high intensity aerobic and strength exercise training does not slow cognitive impairment in people with mild to moderate dementia.
It also said that the exercise program explored “might possibly have worsened cognitive impairment”.
Just under 500 people with dementia took part in the study – 329 were assigned to a four-month aerobic and strength exercise program while 165 were assigned usual care.
The authors, including researchers from the Universities of Oxford and Warwick, found that while the exercise training program improved physical fitness, the benefits do not translate into improvements in cognitive impairment, activities in daily living, behaviour or health-related quality of life.
“Moderate to high intensity aerobic and strength exercise cannot be recommended as a treatment option for cognitive impairment in dementia,” they said.
Associate Professor Michael Woodward, Dementia Australia medical advisor, said the expectation that exercise would go on to reduce the rate of cognitive decline among people with established dementia was probably a little over-optimistic.
“People who have established dementia are probably not going to benefit as much from preventative approaches and we know exercise is predominantly a preventative approach, not a therapeutic approach, at least with respect to cognition and memory,” Woodward explained.
While the study suggested that the exercise program used might have a negative impact of cognitive impairment, Woodward said the deterioration that the researchers saw in the exercise arm was only small. “It was two points on the [Alzheimer’s disease assessment scale-cognitive subscale] ADAS-cog. The ADAS-cog is a scale of about 120 points, so the small change is probably not clinically significant.”
The study’s authors noted that the results disagree with previous studies, but added that these studies might not have achieved as high a dose of exercise. The authors added that some have mixed exercise and cognitive training, making it difficult to isolate the effectiveness of different elements of the training program.
Woodward said while smaller studies have indicated positive effects of exercise, even in those with established dementia, we now have a better constructed and larger trial that has not shown improvements. “It means that we should be cautious about believing that exercise will help people with dementia, at least with respect to their cognition.”
Still, he urged people not to discredit exercise’s well-established role in the prevention of dementia.
“There’s a lot of evidence – and its certainly the recommendation of The Lancet review of dementia prevention – that exercise is the most effective strategy we currently have. So we don’t want people who have normal cognition or even people who have very early changes to their memory starting to believe because of this study that exercise is of no value to them.
“Exercise is an established technique to help reduce our risk of dementia. We also know that there are other preventions that we can do such as keeping socially active, eating a good diet, keeping cognitively active, in other words socially and mentally active.
“These are all very important for the prevention of dementia and this study does not disprove that. This study does not undermine that preventative approach.”Do you have an idea for a story?
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