Moderate to high intensity aerobic and strength training exercises do not delay cognitive decline in people with mild to moderate dementia. It may even make dementia worse. These are the results of a randomized controlled trial published online in the British Medical Journal on May 16.
Nearly 50 million people worldwide have dementia, and about 10 million are diagnosed each year, according to statistics from the World Health Organization. The neurodegenerative disorder presents challenges to families and health and social services. Exercise is thought to potentially delay or prevent dementia, but the evidence is mixed.
To determine whether exercise has a positive effect on cognitive impairment in people with dementia, the National Institute for Health Research (NIHR) in the UK commissioned the Dementia and Physical Activity (DAPA) trial.
Researchers recruited 494 people with mild to moderate dementia, based on Alzheimer’s assessment scales and randomly assigned them either to an exercise program and usual care or usual care only for four months. The 329 assigned to the exercise program participated in gym sessions twice a week for 60 to 90 minutes during which they did 30 minutes of static cycling and lifted weights. They also did home exercises for an extra hour a week.
All participants received usual care, which included counseling for caregivers and families, a clinical assessment, symptomatic treatments, and advice about physical activity.
In addition to cognition, which was measured at 12 months, the researchers also measured participants’ ability to perform daily activities, their quality of life, and neuropsychiatric symptoms as well as the caregivers’ quality of life and burden.
A four-month high-intensity exercise program, added to usual care, did not delay cognitive decline in patients with mild to moderate dementia. Exercise improved physical fitness, but did not improve patients’ ability to perform daily activities or their health-related quality of life.
The researchers conclude that high-intensity exercise is not recommended for people with mild to moderate dementia and that it might temporarily worsen dementia. They suggest that future trials examine other types of exercise, including programs designed to improve physical functioning.