What does physical activity do to the brain?

Readers of our Research Digest may have seen our previous exploration of what loneliness does to the brain.

This month, in keeping with the question, but also in the spirit of our rehab mantra “Movement supports recovery”, and our fundraising challenge “Get moving in May”, we set out to answer the question: what does physical activity do to the brain?  

The terms physical activity and exercise are often used interchangeably. However, they refer to different things. Physical activity refers to voluntary bodily movement produced by skeletal muscles, whilst physical exercise is a focused, structured, and repetitive action. [1] For example, gardening is a physical activity, while running is a physical exercise. Throughout the years, researchers have searched for evidence of the positive effects of physical activity and exercise on the brain. Both are related to healthier lifestyles and seem to bring positive experiences, through the release of endorphins and other processes.  

What is the impact of physical activity on the brain?

Some studies have found that physical activity leads to the release of proteins that promote the development and function of neurons (neurotrophins), resulting in changes to the brain structure. For example, Thomas and colleagues [2] found that physical activity increased hippocampal volume, and promoted the formation of new neurons, which supports memory function and learning. Aerobic exercise, especially dance, has been found to be linked with increased brain plasticity in frontal and temporal areas. [3]  

Physical activity can reduce inflammation in the nervous system, reduce the imbalance between free radicals and antioxidants in our bodies (known as oxidative stress) and excitotoxicity that results in the degeneration of dendrites and cell death. [4] The combined effects of these changes are thought to build brain resilience – the capacity of the brain to adapt to acute stress, trauma, or chronic adversity. With these beneficial effects of physical activity and exercise on the brain, it is not surprising that it has been found to be a protective factor against stroke. [5] 

Is the impact of physical activity on the brain linked to benefits to our lives?

Physical activity and exercise do seem to lead to changes within our brains, but what does that mean for our day-to-day lives? 

Interestingly, there is evidence that the impact of exercise on our lives can start while are still in the womb! Children whose mothers exercised while pregnant did better in oral language tasks and on tests of general intelligence. [6] At present, it is unclear if these effects persist into later life, as most studies investigating the longevity of these effects have been done with animals. Nevertheless, there is evidence of a positive association between cardiovascular fitness and cognitive performance at age 18, which in turn was associated with occupational status and educational achievement later in life. [7] 

Survivors of traumatic brain injury who engage in aerobic exercise experience reduced symptoms of depression. [8] Aerobics classes have also led to reduced disability, and improvements in the quality of life of people with Parkinson’s Disease. [9]  

It may well be the case that not all these benefits are directly linked to changes in the brain, as exercise has a social component, [10] and it often involves contact with nature, which has also been found to bring about cognitive, physical, and psychological benefits. [11] 

In summary, it would seem that whether we run a marathon, play a game of twister with our friends, or are supported to go out in a wheelchair by a partner or care staff, chances are there will be a positive impact on the brain, mind, and wellbeing.  

Please sponsor our “Get moving in May” fundraiser here and help us all keep moving, in May and beyond, because all “movement supports recovery”! 

References 

1. Caspersen, C. J., Powell, K. E., and Christenson, G. M. (1985). Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research. Public Health Reports,100, 126–131. 
2. Thomas, A. G., Dennis, A., Rawlings, N. B., Stagg, C. J., Matthews, L., Morris, M., et al. (2016). Multi-modal characterization of rapid anterior hippocampal volume increase associated with aerobic exercise. Neuroimage, 131, 162–170.  
3. Rehfeld, K., Lüders, A., Hökelmann, A., Lessmann, V., Kaufmann, J., Brigadski, T., et al. (2018). Dance training is superior to repetitive physical exercise in inducing brain plasticity in the elderly. PLoS ONE, 13: e0196636.  
4. Spielman, L. J., Little, J. P., & Klegeris, A. (2016). Physical activity and exercise attenuate neuroinflammation in neurological diseases. Brain Research Bulletin, 125, 19-29.  
5. Kramer, S. F., Hung, S. H., & Brodtmann, A. (2019). The impact of physical activity before and after stroke on stroke risk and recovery: a narrative review. Current Neurology and Neuroscience Reports, 19, 1-9. 
6. Clapp, J. F. III. (1996). Morphometric and neurodevelopmental outcome at age five years of the offspring of women who continued to exercise regularly throughout pregnancy. The Journal of Pediatrics, 129, 856–863.  
7. Aberg, M. A., Pedersen, N. L., Toren, K., Svartengren, M., Bäckstrand, B., Johnsson, T., et al. (2009). Cardiovascular fitness is associated with cognition in young adulthood. PNAS (Proceedings of the National Academy of Sciences), 106, 20906–20911.  
8. Perry SA, Coetzer R, Saville CWN. (2020). The effectiveness of physical exercise as an intervention to reduce depressive symptoms following traumatic brain injury: A meta-analysis and systematic review. Neuropsychological Rehabilitation, 30(3), 564-578.  
9. Robottom, B. J., Gruber-Baldini, A. L., Anderson, K. E., Reich, S. G., Fishman, P. S., Weiner, W. J., et al. (2012). What determines resilience in patients with Parkinson’s disease? Parkinsonism and Related. Disorders, 18, 174–177. 
10. Wankel, L. M., & Berger, B. G. (1990). The psychological and social benefits of sport and physical activity. Journal of Leisure Research, 22(2), 167-182. 
11. Keniger, L. E., Gaston, K. J., Irvine, K. N., & Fuller, R. A. (2013). What are the benefits of interacting with nature? International Journal of Environmental Research and Public Health, 10(3), 913-935.