May 16, 2018

expert reaction to effects of exercise on dementia in old people

A study published in the BMJ investigates the effects of moderate to high-intensity exercise on cognitive impairment and other outcomes in people with mild to moderate dementia.

Dr James Pickett, Head of Research and Development at Alzheimer’s Society, said:

“We know that physical exercise can decrease a person’s risk of developing it, but we understand little about its effect on cognitive decline. In this research, although exercise increased the physical fitness of people involved it did not ease their cognitive symptoms. It’s important to recognise that the study didn’t address how much participants had exercised in the past, and this could have some impact on results.

“With someone developing dementia every three minutes and no way to cure or slow it down, it’s vital to explore ways of slowing the progression of dementia. We want to see more investment in this avenue of research before we assume categorically that exercise is non-beneficial for cognitive function. At Alzheimer’s Society, we fund a broad range of research programmes to understand the condition better, so the 850,000 people living with dementia can live better.

“The results are somewhat surprising as we would anticipate that exercise would have positive effects.

“This study didn’t actually show details of intense exercise worsening dementia – those who exercised did not have a worse cognitive score than those who didn’t. This is only something they suggest in the discussion.

“It is unclear whether any of the participants had a history of engaging in exercise, a life-long history of exercise may still reduce dementia risk.

“The research team only followed up with participants twice at 6 and 12 months to assess their cognitive decline using MCI score. More frequent tests would have provided a better understanding of a participant’s cognitive ability.

“The study wasn’t blinded but this is unavoidable in this type of study.”

Prof Martin Rossor, Professor of Clinical Neurology at UCL, said:

“The evidence that exercise may reduce the risk of developing dementia is convincing. It is not much less clear whether exercise can delay the decline of those with an established dementia. This study would suggest not. The participants included all types of dementia and were mildly or moderately impaired. We know that for Alzheimer’s disease the degeneration of brain cells starts many years before symptoms start and so the likelihood of altering the disease at a late stage is less than with early intervention. So the message remains that exercise is good but to start an exercise regime once the disease is well established may be of limited value.”

Prof Tom Dening, Director of the Centre for Old Age and Dementia at the University of Nottingham, said:

“A good study, well conducted, and I imagine the researchers were disappointed not to find a more positive outcome. However, it may be that cognition and memory aren’t the most suitable outcomes to look for when running an exercise programme. In short, when we join a gym ourselves, we aren’t doing it to improve our memory, are we? We do it in order to get fitter – and this study did exactly that. It’s only because it’s dementia that we get a bit hooked on the memory aspects.

“If people enjoyed it, and if they had improved physical health, then maybe it was worthwhile anyway.”

Dr Brendon Stubbs, Post-doctoral Research Physiotherapist, Institute of Psychiatry, Psychology and Neuroscience, King’s College London:

“The results of the DAPA study are enormously important for the care of people with Alzheimer’s disease and the delivery of care in the NHS and beyond.  Whilst previous smaller studies have suggested that exercise can prevent or improve cognitive decline in people with Alzheimer’s disease, this robust and very large study provides the most definitive answer we have on the role of exercise in mild-moderate Alzheimer’s disease.  The study finds that whilst it is possible for interested people with Alzheimer’s disease to engage in a robust supervised exercise program, this does not appear to delay cognitive decline and does not improve any other outcome besides physical fitness.  The search for effective lifestyle interventions that can delay cognitive decline in dementia must continue.”

Dr Anita McGrogan, Epidemiologist and Senior Lecturer in Pharmacy & Pharmacology at the University of Bath, said:

“The study has been well designed and conducted and the results seem to show either no change in the effect of exercise or a worsening in cognitive impairment.  It is important to note that there was wide variation in ADAS cognitive scores in the participants, with more variation in the exercise group (as shown in figure 2). The exercise and control groups of participants are comparable in terms of their characteristics but those in the exercise group who did comply with the programme had fewer other medical conditions than those assigned to exercise but who did not comply.”

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:

“While there is good evidence to suggest that physical exercise can play an important role in reducing the risk of developing dementia, there has been relatively little research into whether structured exercise programmes could affect the progression of symptoms in people who are already living with the condition.

“This well-conducted study found that a four-month structured high intensity exercise programme did not slow memory and thinking decline in a group of people living with mild to moderate dementia. Some previous studies have linked physical training to an improved ability to carry out everyday tasks, but while this study found the exercise regimen led to an improvement in participants’ physical fitness, this did not translate into greater independence in day-to-day activities.

“This was a high quality trial involving a large number of people with dementia, and while the findings carry significant weight, the researchers note that other forms of exercise may have different effects and this should be explored in future research. There are very few effective treatments for dementia and as scientists work to bring about new life changing medicines, it is important that we continue to see investment in research into other forms of therapy that could help people living with the condition.

“As well as the well-established benefits to physical health, for many people exercise can be a source of enjoyment and provide valuable opportunities for social interaction­. These considerations can apply to people living with dementia just as much as they do to anyone else.”

Prof Rob Howard, Professor of Old Age Psychiatry at UCL, said:

“Whether or not exercise can slow the progress of dementia is an important unanswered question, particularly since no other interventions appear to have any action against dementia. Through the use of a carefully chosen and monitored programme that ensured participants received an impressive “dose” of exercise in terms of intensity and duration, this study has convincingly demonstrated that exercise does not slow decline in cognitive functioning or any of the other features of dementia. Indeed, the participants who were allocated to the exercise intervention actually showed a small worsening of cognitive functioning compared to those who didn’t exercise.

“Although this was only a tiny worsening in cognitive functioning that wouldn’t have been noticeable in an individual patient, it was statistically significantly different from the outcome seen in those who didn’t exercise. Despite its small size, I am sure that – had this been instead an improvement in cognitive functioning with exercise – we would all have been excited about finding something positive in the, so far, depressing fight against dementia. On this basis, I don’t think we should ignore the possibility that exercise might actually be slightly harmful to people with dementia.”

Dr Anne Corbett, Senior Lecturer in Dementia Research at the University of Exeter Medical School, said:

“As you would expect from the BMJ, this is good quality research. The exercise programme didn’t benefit people with dementia, although nor did it perform clinically worse than the control group. Though disappointing, this does reflect the conflicting evidence in the field. Exercise is important for cardiovascular and physical health, social engagement and mental health, so we would not discourage people from taking regular exercise, even if it may not directly improve dementia symptoms.

“Importantly, this study has no bearing on the importance of exercise in preventing dementia in healthy older adults. Exercise is one of the best ways to reduce dementia risk and large trials are needed to deliver an affordable, engaging exercise programme for brain health.”

Dr Elizabeth Coulthard, Consultant Senior Lecturer in Dementia Neurology at the University of Bristol, said:

“While physical exercise is good for general health, recent data cast doubt on a benefit of exercise in people who already have a diagnosis of dementia. This robustly designed study also did not show a benefit of increasing exercise in established dementia. Furthermore, there was a hint that moderate to high intensity activity might even worsen cognition. Based on these data, we cannot recommend exercise as a tool to help slow cognitive decline in dementia.

“There is more research to be done on exercise in dementia. For example, we need to know if certain types of exercise might help balance and reduce falls, and whether the benefit of exercise on general health is still present in people with dementia.

“The findings here are in keeping with the thrust of current research that suggests dementia is hard to modify once it is well established. There has been some promising work on exercise in people with milder symptoms such as those with Mild Cognitive Impairment. Physical activity still holds promise to delay dementia onset in people at risk of developing the disease.

“Broadly, physical activity and healthy ageing go hand in hand. However, targeting physical activity as an intervention to improve specific disease processes is a challenge.”

* ‘Dementia And Physical Activity (DAPA) trial of moderate to high intensity exercise training for people with dementia: randomised controlled trial’ by Sarah E Lamb et al. published in the BMJ on Wednesday 16 May. 

Declared interests

Dr James Pickett: “Nothing to declare.”

Prof Rob Howard: “Nothing to declare.”

Dr Anita McGrogan: “Nothing to declare.”

Dr Brendon Stubbs: “Nothing to declare.”

Prof Tom Dening: “Nothing to declare.”

None others received.