Research has supported exercise as having the potential to keep dementia at bay or at least to impede its progression. A recent study suggests that physical activity may not be as effective at warding off cognitive decline as previously thought.

In this study, published in BMJ (2018; 361, k1675), 329 individuals were assigned to an exercise intervention, while 165 subjects received “usual care.” Average age was 77, and each participant had a clinically confirmed dementia diagnosis.

Those in the exercise group completed two 60- to 90-minute supervised training sessions each week for 4 months; they were asked to exercise for an hour on their own, as well. Supervised sessions included a 5-minute cycling warmup followed by 25 minutes of moderate- to high-intensity cycling. Exercisers also completed a strength training program that featured dumbbell biceps curls, shoulder forward raises, lateral raise or press exercises, and sit-to-stand training exercises using a sit-to-stand weighted vest or a waist belt. Each individual’s strength program was tailored to his or her physical ability; not all participants completed all exercises.

Upon study completion, the exercise group was able to lift more weight, and their high-intensity cardiovascular-activity duration and walking speed had improved. Unfortunately, changes were purely physical. At a 12-month follow-up, cognitive impairment had worsened in both groups, and the decline was slightly greater in exercisers, though the average difference was small enough to make its clinical relevance uncertain.

Bottom line: An exercise intervention did not slow mental decline in dementia patients in this study.