Structured exercise program did not slow cognitive impairment in people with mild or moderate dementia
Scores on the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) at 12 months showed greater cognitive decline in the exercise group.
An exercise training program improved physical fitness but did not slow cognitive impairment in people with mild to moderate dementia, a randomized controlled trial found.
At primary care and other care settings in 15 regions of England, researchers randomly assigned people with mild to moderate dementia to receive usual care only (n=165) or four months of a supervised exercise program involving moderate- to high-intensity aerobic and strength training, in addition to usual care (n=329). The average age of participants was 77 (SD, 7.9) years, and 301 of 494 (61%) were men.
The primary outcome was score on the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) at 12 months. Secondary outcomes were activities of daily living, neuropsychiatric symptoms, health-related quality of life, and caregiver quality of life and burden.
Results were published online on May 16 by The BMJ.
At 12 months, the mean ADAS-cog score increased to 25.2 (SD, 12.3) in the exercise arm and 23.8 (SD, 10.4) in the usual care arm (adjusted between-group difference, −1.4; 95% CI, −2.6 to −0.2; P=0.03), indicating greater cognitive decline in the exercise group. There were no differences in secondary outcomes or in subgroup analyses by dementia type (Alzheimer's disease or other), severity of cognitive impairment, sex, and mobility.
Adherence was high in the exercise group, with more than 65% of participants (214 of 329) attending more than three-quarters of scheduled sessions. In this group, six-minute walking distance improved over six weeks (mean change, 18.1 m; 95% CI, 11.6 m to 24.6 m), although data were only collected in the exercise arm and during the structured intervention period.
The study authors noted limitations, such as the higher number of men than women in the study and the possibility that the period of structured exercise was too short to produce positive benefits beyond physical fitness.
“Moderate to high intensity aerobic and strength exercise cannot be recommended as a treatment option for cognitive impairment in dementia,” they wrote. “Future trials should explore other forms of exercise, including psychomotor protocols that are commonly used in long term neurological conditions where the primary intent is improving physical functioning.”