Lifelong approach to physical activity best for brain health

Dr Helen Macpherson from the Institute for Physical Activity and Nutrition (IPAN) at Deakin University, who conducted the review, said the link between physical activity and brain health may also be different at each stage of life from childhood, mid-life and late life.

"Physical activity has positive effects on brain health at all stages of the lifespan and there is growing evidence that physical activity may help cognition, offer protection against neurodegenerative disorders including Alzheimer’s disease and Parkinson's disease and reduces incidence and severity of many psychological conditions including the common mood disorders, anxiety and depression.

"Traditionally, physical activity was thought to have an indirect effect on these outcomes by reducing the risk for conditions which can affect brain health, such as obesity, diabetes, cardiovascular disease, and cancer.

"However, accumulating evidence from human and animal studies demonstrates physical activity also has a more direct role, enhancing brain health by influencing both structure and function.

"Physical activity is thought to promote neuroplasticity, the ability of the brain to continually adapt throughout the lifespan, and neurogenesis, the generation of new neurons," she said.

Dr Macpherson said the paper had some important findings at the three distinct stages of life: childhood and adolescence, mid-life and older adults.

Physical activity in childhood and adolescence

• There is growing evidence that regular engagement in physical activity during childhood while the brain is still developing may have implications for cognitive development, attention regulation and better memory performance.
• The benefits of physical activity across childhood and adolescence are not limited to cognitive performance and academic achievement - the evidence also points to a number of psychological benefits of physical activity, including the reduction of depression and anxiety  and improvements in self-esteem
• Studies have demonstrated significant relationships between increased physical activity and reductions in attention-deficit hyperactivity disorder (ADHD) and physical activity has also been associated with improved cognitive functioning in children with ADHD.
• There is emerging evidence that early life physical activity may improve cognitive performance many decades later.

Mid-life physical activity and associations with brain health (40-60)

• The influence of physical activity on vascular health at mid-life appears to be particularly important for cognitive and brain health at this life stage and beyond.
• Findings indicate that midlife may act as a critical window for physical activity to slow later life cognitive decline.
• Studies show that regular engagement in physical activity during mid-life may be important for maintenance of strong brain network connections, enhancement of neuroplasticity, and reduction of vascular risk factors.

The influence of physical activity on cognition and brain health in older people

• Declines in cognitive function accelerate after age 60, with processes such as working memory, processing speed and executive function particularly vulnerable to age-related impairment.
• Older adults engaging in extended periods of sedentary behaviour is also recognised as a risk factor for cognitive decline and dementia.
• Studies provides evidence that older people (aged 70-80 years) who have been involved in 150 min/week of moderate to vigorous physical activity in the previous 5 or more years have a 40 per cent lower chance of developing Alzheimer's disease.
• In older people it appears that it may be important to exercise at an intensity that will improve cardiorespiratory fitness, rather than simply breaking up sedentary behaviour to elicit even more protective effects on the brain.
• In old age, relatively short term increases in physical activity participation can positively impact cognitive function. Both aerobic (eg. walking, jogging, swimming) and resistance training (eg. weights and strength building exercises) have demonstrated cognitive benefits in older people.
• It is likely that interventions to increase physical activity will be most effective to prevent or delay dementia when implemented prior to the onset of cognitive decline.

The paper can be found at: http://journal.frontiersin.org/article/10.3389/fnagi.2017.00147/full