Physical activity and mental health in older adults

This is an excerpt from Physiology of Exercise and Healthy Aging-2nd Edition by Albert W. Taylor & Michel J. Johnson.

By Andrea Lazosky PhD, C Psych, ABCN/ABPP

The Role of Physical Activity on ­Mental Health With Aging

Once encouraged for prevention of chronic disease alone, it is now recognized that participation in physical activity such as leisure pursuits, hobbies, and ­house and yard work, positively influences ­mental health in older adults. Maintaining an active lifestyle improves ­mental health and may prevent ­mental health prob­lems like depression among el­derly ­people. It may also delay functional decline and help manage both depression and dementia. Deslandes et al. (2009) suggest that exercise has a positive relationship with outcome in depression and neurodegenerative diseases, as well as quality of life. Conversely, a sedentary lifestyle, among other ­factors, is significantly correlated with depression morbidity in ­later life (Blay et al. 2007).

Bauman et al. (2016) pre­sent a conceptual framework (see figure 9.1) for the effects of physical activity on the physiology of aging that encompasses chronic disease prevention and risk reduction, functional status outcomes, psychological well-­being, and social outcomes. The biological mechanisms by which physical activity affects brain health and, in turn, ­mental health remains poorly understood, but ­there have been some intriguing findings:

• Control of cardiovascular risk ­factors: Chronic disease prevention predominantly targets cardiovascular risk ­factors that have been shown to impact both LLD and cognitive decline. Exercise, including moderate intensity aerobic activity and muscle strength training, has been established as a benefit in the prevention and control of diabetes (see chapter 5), hypertension, and other forms of cardiovascular disease (see chapter 1).
• Impact on incidence of dementia: Physically active older adults have a reduced risk of cognitive decline and dementia (Blondell et al. 2014; see also chapter 3). Both aerobic exercise and re­sis­tance training have shown positive effects on cognition, including executive function, attention, and pro­cessing speed (Scherder et al. 2014). Risk of developing Parkinson’s disease is lower in physically active older adults, and exercise has benefits to strength, walking, motor control, and balance in individuals with a Parkinson’s diagnosis (Bauman et al. 2016).
• Stimulation of brain-­derived neurotrophic ­factor: The production of brain-­derived neurotrophic ­factor (BDNF) is stimulated by aerobic physical activity. BDNF is a protein involved in preventing neuronal loss and increasing the growth, differentiation, and survival of neurons (Dinoff et al. 2016).
• Increased brain volume: Magnetic resonance imaging (MRI) of the brain has been used to show that aerobic fitness training, but not nonaerobic stretching and toning exercises, significantly increases brain volume in older adults. Colcombe et al. (2006) showed increased brain volume over a 6-­month trial in an aerobic exercise group in both gray and white ­matter (predominantly) in the prefrontal cortex and temporal lobe cortex, brain regions previously shown to have substantial age-­related deterioration. In another study, greater physical activity predicted greater volumes of frontal, occipital, and medial temporal regions of the brain nine years ­later (Erickson et al. 2010). More specifically, Erickson et al. (2011) found that aerobic exercise selectively increases anterior hippocampal volume and improves spatial memory in older adults, effectively reversing age-­related volume loss by 1 to 2 years. They also found a relationship between hippocampal volume and BDNF, with increased hippocampal volume associated with higher serum levels of BDNF.