Exercise as it relates to Disease/Does physical activity reduce the symptoms of Alzheimer's Disease?

This is a critical analysis of the article from the Journal of Rehabilitation Research and Development "Exercise and Activity Level in Alzheimers's Disease: A Potential Treatment Focus" - Linda Teri, Susan M Mccurry, Rebecca Logsdon, Andrea Lacroix (1998)

What is the background to this research?
Dementia is a collective name for progressing brain syndromes which affects memory, thinking, behaviour and emotion. Dementia is extremely prevalent worldwide with an estimated 44 million people experiencing some form of the disease. The most common form of dementia is Alzheimer's Disease (AD), and currently accounts for 50-60% of all dementias. Unavoidable risk factors for developing AD include ageing, family history of AD and carrying certain genes.

There is currently no cure for Alzheimer's Disease. There are some medications available that can reduce symptoms and improve quality of life for some people, but fail to prevent progression of the disease. Although the association between physical activity and Alzheimer’s Disease has received little attention, the studies that do exist indicate a consistent adverse relationship between the two. The primary purpose of this study was to identify if it is beneficial for individuals that have been diagnosed with AD to participate in an exercise program.

Where is the research from?
Subjects were recruited from an ongoing, community-based Alzheimer's Disease Patient Registry (ADPR). There are approximately 23,000 persons over the age of 60 who are currently under the care of the registry. The leading author Linda Teri PhD has been at the University of Washington since 1984, and the school of nursing since 1998. She has done numerous studies on cognitive impairment and ageing. She has authored over 260 journal articles in peer-reviewed high impact journals, collaborated on over 450 scholarly presentations and co-authored five books.

The study was funded with a grant from the National Institute of Ageing. The National Institute of Ageing has been conducting research on ageing since 1974. They are seen as a trustworthy organisation and have undertaken several studies on what causes AD and possible interventions. Therefore, due to the experience of both the Author and National Institute of Ageing, it is unlikely that there was any bias present throughout this study.

What kind of research was this?
It is a prospective observational study with specific eligibility criteria that each participant had to meet to be chosen for the study. Only subjects who met the National Institute of Alzheimer's Disease and Related Disorders Association criteria for probable or possible AD were eligible to participate. Additionally, subjects had to have an actively involved caregiver living with them who was willing to participate in treatment sessions.

Several meta-analyses’ have been conducted on the relationship between exercise on AD. The meta-analyses’ consisted of a combination of cross-sectional studies and randomised controlled trials. The results show aerobic exercise can lead to attenuation of age-related grey matter volume loss and better cognitive assessment scores after 6-12 months. The more extensive results are most likely due to it being made up of a collection of studies that were conducted more recently.

What did the research involve?
The study consisted of 30 participants (male n=22, female n=8; mean age 78 yrs, mean time demented 4.3 years). Subjects participated in a 12-week exercise training program that consisted of aerobic activities, strength training, balance and flexibility training. The strength training portion focused on lower body exercises that were to be completed on 3 non-consecutive days per week. Participants were initially taught exercises without weights and were individually assessed to see if they could safely increase the load or volume of their training. Alternating with strength training, the subjects completed endurance training with the goal being to increase exercise duration. Participants were asked to walk at least 30 minutes on a minimum of 3 non-consecutive days each week. Balance and flexibility exercises were recommended for 10-15 minutes as part of a warm-up or cool-down to strength or endurance activities. This methodology was appropriate for this study because it simultaneously allowed for adequate recovery between training sessions while developing each aspect of physical fitness that is required to reduce the risk of falls and injury while performing everyday tasks. Having a caregiver log the adherence would be appropriate in most cases as they have a good understanding of the subject's ability and how they are feeling. It is unlikely that they would say the subject completed more physical activity than they actually did because they are looking for an improvement in the health of their subject. Limitations of this study can be seen with the small number of participants. With over 23,000 subjects under the care of ADPR, they could have recruited more subjects to get involved with this study. Furthermore, a control group (completing the same exercise program) consisting of same-aged individuals unaffected by AD would be appropriate to compare with the results of the study. This could have resulted in a more accurate representation of the results as opposed to comparing it with pre-recorded normative data.

What were the basic results?
Baseline data revealed a consistent pattern of impaired performance on measures of walking speed, functional reach, and standing balance when compared to published data on nondemented older adults. Adherence was very good with 100% of subjects attempting some exercises during the 12-week intervention, and one third completed all exercises that were assigned. For caregivers, the exercise program was well received, since it offered a practical, positive step that subjects, and caregivers could take.

Challenges that the authors identified during the intervention period included; It was summarised that persons with AD can participate in a systemic exercise program under the guidance of family caregivers. The author does acknowledge that more research is needed in this area to be able to evaluate a treatment outcome.
 * Declining physical health of the subject and caregiver
 * Cognitive deficits and behavioural problems of the demented person
 * The caregivers' style of interacting with the subject

What conclusions can we take from this research?
The information gathered during this study doesn't provide enough evidence to prove that exercise decreases the effects of Alzheimer's Disease. However, I do feel that this study had a positive influence on the research in this area identifying the benefits for individuals diagnosed with AD to engage in an exercise program that works on developing strength, endurance, balance and coordination.

Since the release of this study, more research has been conducted in this area. Findings are still unclear, however, there have been some indications that regular physical activity can improve cognitive function. Therefore, to get conclusive evidence and a better understanding of the effects of physical activity and AD more research needs to be conducted in this area.

Practical Advice
Those interested in undertaking a physical activity training program should undertake a pre-exercise health screening prior to beginning any exercise. Individuals should aim for at least 150 minutes of moderate intensity exercise each week.. This should be made up of a combination of strength training and endurance exercise. Other benefits may come about by incorporating balance and coordination exercises into warm-ups or cool-downs. Exercise technique is critical to the success of this intervention and must be done in a way that isn't causing more harm. Learning correct technique may be difficult for some of the older population due to mobility restrictions, lack of knowledge and difficulty retaining information.

Further Readings
Information on Dementia: Benefits of Exercise: Exercise Program:
 * https://www.dementia.org.au/
 * https://www.alz.co.uk/
 * https://yourbrainmatters.org.au/
 * https://www.alzheimersresearchuk.org/about-dementia/helpful-information/the-brain-tour/
 * https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dementia-activities-and-exercise