Moderate to high intensity exercise programmes do not slow cognitive impairment in older people with dementia, according to findings from a UK study.
Although the exercise programme improved physical fitness, it cannot be recommended as a treatment option for cognitive impairment in dementia, said those behind the new study.
“A moderate to high intensity aerobic and strength exercise training programme does not slow cognitive impairment”
The view that exercise might slow cognitive decline has gained widespread popularity in recent years, noted the researchers from the University of Oxford and the University of Warwick.
However, they highlighted that recent reviews of trials of exercise training in people with dementia had shown conflicting results.
As a result, they decided to estimate the effect of a moderate to high intensity aerobic and strength exercise training programme on cognitive impairment and other outcomes in people with dementia.
Their trial, published in the British Medical Journal, involved 494 people with mild to moderate dementia – and with an average age of 77 – living in the community across 15 regions of England.
General health and fitness was assessed at the start of the study and participants were randomly assigned to either a supervised exercise and support programme or to usual care.
“The exercise training programme improved physical fitness”
The exercise programme consisted of 60 to 90 minute group sessions in a gym twice a week for four months, plus home exercises for one additional hour each week with ongoing support.
The primary outcome was an Alzheimer’s disease assessment score (ADAS-cog) at 12 months, with secondary outcomes including activities of daily living, number of falls, and quality of life.
Compliance with the exercise programme was good and participants were assessed again at six and 12 months, said the researchers.
However, after taking account of potentially influential factors, the researchers found that cognitive impairment declined over the 12-month follow-up in both groups.
The exercise group showed improved physical fitness in the short term, but higher ADAS-cog scores at 12 months – 25.2 versus 23.8 – compared with the usual care group, indicating worse cognitive impairment. However, the average difference was small and clinical relevance was uncertain.
“We would still strongly encourage people of all health levels to take regular exercise”
Meanwhile, no differences were found in secondary outcomes, including number of falls and quality of life, or after further analyses to test the strength of the results.
The study authors said: “This trial suggests that people with mild to moderate dementia can engage and comply with moderate to high intensity aerobic and strengthening exercise and improve physical fitness.
“These benefits do not, however, translate into improvements in cognitive impairment, activities in daily living, behaviour, or health related quality of life,” they stated.
They suggested future trials should explore other forms of exercise and that researchers “should consider the possibility that some types of exercise intervention might worsen cognitive impairment”.
Dr Hilda Hayo, chief executive and chief Admiral nurse at the charity Dementia UK, said she welcomed any study “leading to a greater understanding of dementia”.
“While this study found that exercise does not improve cognition for people with dementia, we would still strongly encourage people of all health levels to take regular exercise,” said Dr Hayo.
“There is much evidence that what is good for the heart is good for the brain, so exercising throughout your life can potentially delay a diagnosis of dementia, particularly vascular dementia, or reduce its symptoms,” she said.
She added: “Gentle exercise such as walking outside or armchair aerobics can improve a person with dementia’s mood and provide some connection to other people.”