David Cohen, M.D.·Published 10 December 2013·9 min read
Key points
Regular exercise can help people with dementia think a little more clearly, and care for themselves a bit more, a new study finds.
In 2012, the World Health Organization declared dementia to be a public health priority (World Health Organization 2012), citing the high global prevalence and economic impact on families, communities, and health service providers.
Several recent trials and systematic reviews of the impact of exercise on people with dementia are reporting promising findings.
We identified trials for inclusion in the review by searching ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group’s Specialised Register, on 4 September 2011, and again on 13 August 2012.
Regular exercise can help people with dementia think a little more clearly, and care for themselves a bit more, a new study finds.
"If the person with dementia is living at home, there are usually exercise programs offered at community day programs for persons with dementia. I would encourage family caregivers to connect with these programs and/or home care to learn about the available resources in their community," said Dorothy Forbes, an associate professor at the Faculty of Nursing, University of Alberta in Edmonton, who led the study.
For patients with dementia who can no longer live at home, "Most residential settings should be offering exercise programs for their residents," Dr. Zaldy Tan, a dementia expert who was not involved in the new study, told Reuters Health. "If not, family caregivers may wish to advocate for these."
People are considered to have dementia if their mental function is bad enough to interfere with daily activities. Alzheimer's disease is the most common cause, accounting for about 60 to 80 percent of cases. The next most common cause of dementia is stroke.
Dementia leads to poorer quality of life for patients, and it also puts a burden on families and caregivers - as Forbes, who led the study, knows all too well.
"For over 20 years I worked as a community health nurse where health promotion was my focus and in home care where I attempted to support and provide the needed resources with many family caregivers and persons with dementia in rural and inner city homes," Forbes told Reuters Health in an email. "My mother also had dementia and died in an acute care setting where the health care providers did not understand how to care for her dementia symptoms."
"These experiences made me realize how difficult it was to care for someone with dementia at home and in other care settings, especially with little knowledge about what was helpful in managing the symptoms and available resources," Forbes said.
"There is strong evidence regarding the benefits of exercise on older adults, but we did not know if there were benefits for persons diagnosed with dementia," she explained.
In 2006, therefore, when "there was little research conducted in this area," Forbes and her colleagues pooled the data from four studies of the role of exercise for patients with dementia. Their new study, published online by the Cochrane Library, is an update of that earlier effort.
"This updated review includes 16 trials," Forbes said. "We plan to do another update in six months as additional trials have already come to our attention. There is now a great deal of interest in this area of research."
The 16 trials altogether involved nearly a thousand elderly adults with dementia. Each trial tested the effects of exercise programs on such outcomes as thinking skills, activities of daily living, challenging behavior, and depression.
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All 16 trials were so-called "randomized, controlled studies," which means the research teams used the most dependable methods. Even so, the studies utilized different types and duration of exercise programs, and the participants were in different stages of dementia, so the results were not uniform.
Still, despite the differing nature of the studies, Forbes and her team found that on average, exercise improved cognitive functioning and the ability to perform activities of daily living.
"Exercise is not only beneficial for older adults (in general) but also for persons with dementia in delaying memory problems and prolonging their ability to care for themselves (i.e., activities of daily living such as dressing, bathing)," Forbes said.
Exercise didn't have an effect on depression or mood, however, and there wasn't enough evidence to draw firm conclusions about its effects on other outcomes.
"I think it's really important topic," Tan, who is the medical director of the Alzheimer's and Dementia Care Program at the University of California, Los Angeles, told Reuters Health.
"The challenge here is, as the authors pointed out, that these studies they reviewed were quite heterogeneous," he said.
"But with that said," he added, "it's promising that even with quite different interventions and studies, they found that it appears to be beneficial for cognition and also activities of daily living."
Tan sees a practical side to exercise that goes beyond its impact on measurable cognitive skills.
"I think exercise is one intervention that's going to turn out to be good for other things like, for example, reducing one's risk for falls," he said. "Falling is one thing that is a big problem for people with dementia."
Tan expects to see more research in the future, including studies of how exercise programs might affect the children and caregivers of people with dementia.
In 2012, the World Health Organization declared dementia to be a public health priority (World Health Organization 2012), citing the high global prevalence and economic impact on families, communities, and health service providers. In the coming decades, with the aging of the population, the number of individuals living with dementia in our communities will rise dramatically. This will increase the burden on family caregivers, community care, and residential care services (Alzheimer Society of Canada 2010; World Alzheimer Report 2011). People diagnosed with dementia often have unique needs, as they tend to be older and present with acquired impairment in memory, associated with other disturbances of higher cortical function, or personality changes (APA 1995; McKhann 1984). As a first approach, best practice guidelines currently recommend the exploration of behavioural and psychological interventions before initiating pharmacological interventions, due to the limited benefit of pharmacological treatments in reducing functional decline and their potential side effects (Forbes 2008a; Hogan 2008). Exercise is among the potential protective lifestyle factors identified as a strategy for treating the symptoms of dementia or delaying its progression (Lautenschlager 2010).
Background
This is an update of our previous 2008 review. Several recent trials and systematic reviews of the impact of exercise on people with dementia are reporting promising findings. Objectives
Primary: Do exercise programs for older people with dementia improve cognition, activities of daily living (ADLs), challenging behaviour, depression, and mortality in older people with dementia?
Secondary: Do exercise programs for older people with dementia have an indirect impact on family caregivers’ burden, quality of life, and mortality?
Do exercise programs for older people with dementia reduce the use of healthcare services (e.g. visits to the emergency department) by participants and their family caregivers?
Search methods
We identified trials for inclusion in the review by searching ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group’s Specialised Register, on 4 September 2011, and again on 13 August 2012. The search terms used were: 'physical activity' OR exercise OR cycling OR swim* OR gym* OR walk* OR danc* OR yoga OR 'tai chi'.
How the intervention might work
Physical activity, as defined for this review, refers to "body movement that is produced by the contraction of skeletal muscles and that increases energy expenditure" (Chodzko-Zajko 2009). Exercise refers to "planned, structured, and repetitive movement to improve or maintain one or more components of physical fitness" (Chodzko-Zajko 2009). There are several potential mechanisms that link exercise programs, which include physical activity to cognitive function. A detailed examination of the potential mechanism(s) is beyond the scope of this review. For further information the reader is directed to two recent reviews, Erickson 2012 and Davenport 2012. Briefly, exercise improves vascular health by reducing blood pressure (Fleg 2012), arterial stiffness (Fleg 2012), oxidative stress (Covas 2002), systemic inflammation (Lavie 2011), and enhances endothelial dysfunction (Ghisi 2010), all of which are associated in the maintenance of cerebral perfusion (Churchill 2002; Davenport 2012; Rogers 1990). Recent evidence has shown a strong association between cerebral perfusion (i.e. balance between the supply and demand of nutrients to the brain), cognitive function, and fitness in older healthy adults (Brown 2010). Furthermore, insulin resistance or glucose intolerance is linked with amyloid β plaque formation (Farris 2003; Wareham 2000; Watson 2003), which is a feature of AD. Exercise is known to enhance insulin sensitivity and glucose control (Ryan 2000). Exercise may also preserve neuronal structure and promote neurogenesis, synaptogenesis, and capillarization (formation of nerve cells, the gaps between them, and blood vessels, respectively) (Colcombe 2003), which may be associated with exercise-induced elevation in brain-derived neurotrophic factor (BDNF) (Vaynman 2004), and insulin-like growth factors (Cotman 2007). Animal and human studies investigating the role of BDNF provide evidence that BDNF supports the health and growth of neurons and may regulate neuroplasticity (adaptability of the brain) as we age (Cheng 2003; Vaynman 2004). Intlekofer 2012 recently reported that exercise reinstates hippocampal function by enhancing the expression of BDNF and other growth factors that promote neurogenesis, angiogenesis (formation of blood vessels), and synaptic plasticity. Taken together, animal and human studies indicate that exercise provides a powerful stimulus that can counteract the molecular changes that underlie the progressive loss of hippocampal function in advanced age and AD (Erickson 2012).
Summary of main results
This review included 16 trials (17 articles) with a total of 937 participants. Most participants were older people with AD. The exercise programs varied greatly; the length of time that they ran ranged from two weeks to 12 months, and activities varied (e.g. hand movements, sitting, walking, and upper and lower limb exercises). The review suggests that exercise programs may have a significant impact on improving cognitive functioning and the ability to perform ADLs in people with dementia. There was substantial and considerable unexplained statistical heterogeneity observed in the cognitive and ADL analyses, respectively, which suggests the need for caution in interpreting these results. Indeed, when we removed the Venturelli 2011 trial from the cognitive analysis - since it was the only trial that included only people with moderate to severe dementia - the heterogeneity was reduced, and the results of this meta-analysis were no longer significant. In addition, our findings reveal that the burden experienced by informal caregivers providing care in the home may be reduced if they supervise their family member with dementia during participation in an exercise program. This review found no significant effect of exercise on challenging behaviours or depression. Nevertheless, these are encouraging results, as dementia is a debilitating disease that results in progressive decline in cognition and ability to perform ADLs, as well as other symptoms. A slowing of both cognitive decline and the development of dependence in ADLs is critical for enhancing the quality of life for people with dementia, and will have an impact on the family caregivers’ ability to sustain their caregiving role.
Authors' conclusions
With an increased number of trials now available, there is evidence that suggests that exercise programs could have a significant impact on improving cognitive functioning and ability to perform activities of daily living (ADLs) in people with dementia. Healthcare providers who work with people with dementia and their caregivers should feel confident in promoting exercise among this population, as decreasing the progression of cognitive decline and dependence in ADLs will have significant benefits for people with dementia and their family caregivers’ quality of life, and possibly delay the need for placement in long-term care settings. No trials reported adverse events related to exercise programs.
One trial that examined the burden experienced by family caregivers who provide care in the home revealed that this burden can be reduced if they supervise their family member with dementia during participation in an exercise program. Therefore, encouraging caregivers to participate in exercise may also have a beneficial impact on their quality of life.
Setting (home versus institutional) can be considered in the future, if more studies become available. There was an insufficient number of trials to permit subgroup analyses that would determine which type of exercise (aerobic, strength training, balance), at what frequency and duration, is most beneficial for specific types and severity of dementia. Clearly further research is needed to be able to develop best practice guidelines that would be helpful to healthcare providers in advising people with dementia living in institutional and community settings.
Dorothy Forbes, Emily J Thiessen, Catherine M Blake, Scott C Forbes, Sean Forbes
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