Ageing, Exercise, and Neurodegeneration

Ageing is thought to be the highest risk factor for neurodegenerative conditions such as dementia. Dementia is characterised by the progressive decline in cognitive functions and memory. The WHO indicates that worldwide, approximately 47 million people suffer from dementia, the most common form being Alzheimer’s disease; the predictions are that this number is set to triple by 2030. In an era of increased longevity, what can we do to minimise the risk of developing dementia, a condition for which there is presently no cure?

Lifestyle choices are frequently cited a prerequisite for a number of neuronal and systemic disease processes. A lack of physical activity, dietary choices, alcohol consumption, and smoking may singularly impart an increased mortality rate. Most likely, the risk factors for dementia are multifarious and include factors other than lifestyle, such as genetics; however, any lifestyle choice that has an impact on the brain could potentially impact the processes that accelerate neurodegeneration away from the normal ageing process.

Could exercise be a modifier of the ageing process, decrease the risk of developing dementia, and moderate symptoms of dementia? It is already well established that moderate exercise has multiple benefits on our physiological and mental wellbeing. Growing evidence is now supporting a positive role for physical activity in both the ageing process and in a protective capacity in relation to dementia. Various studies have demonstrated that physical activity—in particular, aerobic exercise—may act to attenuate the risk of developing dementia and slow the process of cognitive decline. Patients with Alzheimer’s disease that exercise for one hour twice a week show a slower decline in activities of daily living (i.e. eating, bathing, dressing etc.) [1]. Walking in elderly men has been shown to reduce the risk of developing dementia [2]. And, finally but importantly, those that exercised pre-diagnosis saw an increase in cognitive decline when they decreased their exercise levels when compared to those that maintained their physical activities [3].

Whether physical activity alone can alter the course of dementia progression or if other lifestyle factors also contribute, remains to be established. It is an intriguing concept that physical activity may either slow the development of cognitive changes associated with dementia, delaying the onset of the disease or ultimately prevent the initiation of the pathology. In the meantime, exercise has many benefits that may protect the body during the advancing years and help alleviate some of the symptoms following diagnosis. Some of the benefits include:

• Improved strength, core stability and flexibility: Strength and flexibility declines with age. Falls and postural instability are observed in ageing and dementia-related conditions; strengthening and core exercise may temper this risk.
• Improved bone density due to weight-bearing activities, such as walking and yoga: Bone density decreases with age, increasing the risk of fractures. These can also reduce the risk of osteoarthritis.
• The neurotransmitter release during exercise has a positive impact on our mental well being: Depression is often observed in conditions such as Alzheimer’s disease and Parkinson’s disease.
• Exercise is important for cardiovascular health and prevention of other conditions such as Type II diabetes and strokes.

Collectively, exercise leads to physiological, psychological, and biochemical improvements. Exercise may not be a cure for dementia, but if followed during one’s lifetime, it may ensure that the balance of a healthy lifestyle provides protection against some of the declines seen in ageing and the risk of developing a neurodegenerative condition. It cannot be excluded that there may be limitations in the ability to exercise due to pre-existing conditions or, if the dementia is progressing, the decline in cognitive function may preclude certain activities. In addition, there are still many unanswered questions and future research will establish the required duration, intensity and frequency required. In the meantime, I shall just tie up my laces and consider that I am keeping myself brain-fit as well as heart-fit.

1. Rolland, Y., et al., An exercise program for nursing home residents with Alzheimer's disease: a 1-year randomized, controlled trial. J Am Geriatr Soc, 2007. 55(2): p. 158-65.

2. Abbott, R.D., et al., Walking and dementia in physically capable elderly men. JAMA, 2004. 292(12): p. 1447-1453.

3. Soni, M., et al., Physical activity pre- and post-dementia: English Longitudinal Study of Ageing. Aging Ment Health, 2017: p. 1-7.