Doubts about Exercise Benefits for Dementia
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Regular exercise has been one of the main recommendations for people living with dementia to help stave off further cognitive decline, along with a diet rich in nuts, seeds, leafy green vegetables, fish, poultry and olive oil, new and stimulating activities and maintaining social engagement. Now a new study published in the British Medical Journal suggests some forms of exercise don’t make a difference and may slightly worsen thinking and memory skills.
The study, carried out by a UK team led by Oxford University, set out to understand whether an exercise regime could be prescribed by the NHS as a treatment for mild to moderate dementia. The team recruited almost 500 people living with mild to moderate dementia and split them randomly 2:1 into a larger group which undertook a tailored exercise programme and a control group which received normal care. All participants were tested on their current level of cognitive impairment at the outset. The exercise group went through a 4 month programme of moderate to high intensity aerobic and strength training, primarily using cycling and weights. Almost two thirds of the exercise group completed the programme. All participants were followed up with repeat testing at 6 and 12 months.
The results showed the exercise group’s memory and thinking skills had declined slightly more than the control group, which carried on with life as normal. The researchers say the difference was small, but significant enough to advise clinicians that moderate to high intensity aerobic exercise can’t be recommended as a treatment for mild to moderate dementia and may actually worsen cognitive impairment.
So where does that leave us in the fight against dementia? Previous studies have suggested exercise has a protective and beneficial effect, but the UK team states research programmes haven’t always been robustly designed. It’s important to note that the participants in this trial had already received a diagnosis of dementia and they went through a particular type of training. Other research shows that high intensity exercise in healthy people can temporarily starve parts of the brain of oxygen with a temporary reduction in thinking skills, from which they recover easily. It may be that people with dementia don’t have the same resilience; there may also be a difference in response from people currently living with Mild Cognitive Impairment, which can be a precursor to dementia. The study also didn’t look at lower impact forms of exercise, such as walking or swimming; current guidelines suggest 150 minutes of moderate exercise a week is valuable and many people report it makes them feel better.
Other interventions include the MIND diet, which is well researched and has been shown to have a protective effect for Alzheimer’s and vascular dementia, even for people who don’t follow it to the letter. Last year the Lancet Commission also identified tackling hearing loss and maintaining social engagement as important to prevent or delay the onset of dementia. The Commission recommended lifestyle changes in middle age, including more exercise, as a key factors to prevent deteriorating brain health in older age. The Dementia and Physical Activity study didn’t look at exercise as a preventative measure against onset of dementia, but as a potential treatment to delay further decline once a diagnosis had been made. If the study had shown positive effects, we would all be climbing on our bikes and pedaling hard – the slight negative effect is pause for thought and goes to show how little we still know about this condition.
Read the full BMJ article here