A study from researchers at the University of Oxford reported that exercise did not benefit patients with dementia, and actually worsened their cognition . Although surprising, a closer look at these findings in the context of previous research provides a clearer picture.
This large clinical trial assigned 329 dementia patients to participate in an aerobic and strength exercise program while a separate 165 patients maintained their normal activity level. Over four months, the exercise patients attended group exercise sessions twice a week. They rode a stationary bicycle for 30 minutes at moderate to hard intensity and performed strength training with weights. They were also asked to exercise for an additional hour each week on their own. After four months, the researchers asked the exercise group to perform 150 minutes of physical activity each week at home for another eight months.
Physical fitness improved in the exercise group after six weeks. However, after a year, the exercise group was more cognitively impaired than the normal group. Previous smaller clinical trials have reported mixed results of exercise in patients with dementia. Exercise provided a moderate cognitive benefit in many studies but no benefit in others . In this study, exercise increased cognitive impairment in dementia patients, but the authors note that the difference between the two groups was small and may not be clinically meaningful. As a whole, the clinical evidence suggests exercise may provide a minor cognitive benefit to dementia patients, but that conclusion is still uncertain.
There is, however, strong evidence that lifelong exercise can lower your future risk for Alzheimer's disease. In fact, a recent review that combined epidemiology studies ranging in length from 3.9 to 31 years and including 23,345 people showed that exercise can reduce your Alzheimer's disease risk by up to 35% . Another recent study reported that middle-aged women who were more physically fit were up to 88% less likely to develop dementia.
How does exercise reduce your risk for dementia? Exercise improves cardiovascular and metabolic health, both of which are important for brain health. Studies suggest it may also reduce inflammation and cholesterol, promote the generation of new neurons, and increase beneficial growth factors in the brain .
Although it is not clear whether exercise will slow cognitive decline in patients who have already been diagnosed with Alzheimer's disease, lifelong exercise is an important dementia prevention strategy. It can reduce your risk and is an important component of any plan for brain health.
Nick McKeehan is Assistant Director, Aging and Alzheimer's Prevention at the Alzheimer’s Drug Discovery Foundation. He served as Chief Intern at Mid Atlantic Bio Angels (MABA) and was a research technician at Albert Einstein College of Medicine investigating repair capabilities of the brain. He received a bachelor of science degree in biology from Purdue University, where he was awarded a Howard Hughes Scholarship. Mr. McKeehan also writes about the biotechnology industry for 1st Pitch Life Science.
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