• susanherdman

Effect of Exercise on Memory

For me November brings to mind the importance of memory…Whether it be remembering the importance of paying tribute to both our current and fallen veterans on Remembrance Day or perhaps just simply remembering where you’ve placed your wallet, keys, and/or cellphone yet again…

Memory plays an important role in our lives – enriching us with the recollection of the love of our family and friends, allowing us to re-live past adventures, as well as helping us to learn from our mistakes and better adapt for our future (1). There are 3 general processes involved in memory:

  1. Encoding = information (eg. I put my keys on the kitchen counter) gets transformed into a neural code in your brain (1). This generally requires a certain level of attention (1) as it’s hard to remember where you put your keys if you weren’t really paying any attention to begin with…).

  2. Storage = the ability of the brain to retain this info over time – commonly described as “short-term” and “long-term” memory (1).

  3. Retrieval = ability to access this stored information (1).


A recent study in 2021 found that a mere 20mins of moderate-to-high intensity exercise (in this case running on a treadmill, working at approximately 75% of heart rate reserve) was found to improve all 3 processes of memory – encoding, storage, and retrieval (at both 1 hour and 24 hours later) (2).

Cycling for 30mins has also been shown to help improve memory (3). Now both of these studies were done on young, healthy adults… What about with older adults – especially those who want to prevent the dreaded dementia and Alzheimer’s?

Normally with aging, brains generally lose both size and density of grey and white matter (4,5,6) resulting in mild changes in memory such as occasionally having to search for the right word or forgetting events from years long ago (7). According to the Alzheimer Society of Canada, almost 40% of people over age 65 have some form of memory loss, but the majority will only be mild (called “age-associated memory impairment”) and will not disrupt their functioning (8).

Healthy brain on L vs Advanced Alzheimer’s brain on R (note the loss of volume and brain tissue)

With Alzheimer’s – there are additional plaques and tangles that result in more aggressive loss of brain density and volume (9) and would result in symptoms such as consistently pausing/struggling to find words on a daily basis and/or forgetting details about events that happened recently (7).


Domingos et al. recently summarized the results from 32 different studies (totaling approximately 5,058 subjects, with an average age between 60 and 78 years old) about the effect of physical activity on brain function and structure (10). They found overwhelming evidence that being physically active has been shown to:

  • increase the physical volume of your brain! (bigger brain = more space for remembering where your keys, wallet, AND cellphone are) (10).

  • increase the density of grey matter (in this case, a dense brain is a good thing!) (10).

  • improve the quality of the connections between neurons as well as the blood vessels feeding your brain (thereby allowing your brain to process/access info more quickly/efficiently) (10).


The best news of all is that all of these positive effects of exercise have been noted in regions of the brain that are most typically damaged in dementia (10):

  • the hippocampus (which is responsible for encoding, storing, organizing, and accessing memories)(11),

  • the frontal lobes (which are involved in higher level thinking, planning, problem solving, and controlling body movements) (11),

  • and the temporal lobes (which processes/makes sense of incoming auditory information, verbal memory, and visual memory) (11).


How much exercise do I need to help prevent dementia?

The exact “formula” is still being researched; however, the general pattern remains. Those who are sedentary tend to lose approximately 1% of their hippocampus per year after the age of 50, whereas those who are regularly physically active are able to slow down or even stop this decline entirely (10). The Heart and Stroke Foundation of Canada, Canadian Society of Exercise Physiology, and Public Health Agency of Canada all recommend 150 minutes of moderate intensity (ie. 5-6 on a 10-point scale) or 75 minutes of vigorous (ie. 7-8/10) activity per week (10,12,13,14). But something (even light intensity) is better than nothing (10).


Don’t let an injury or pain stop you from being physically active – reach out to any of us at InReach Physio about helping you recover from an injury, manage your pain, and help you design a physical activity exercise program that works for you! Your brain will thank-you!


By: Susan Herdman, Registered Physiotherapist


Book a telephysio / online physio / virtual physio / video physiotherapy appointment with a registered physiotherapist in British Columbia. InReach Online Physio services communities in northern and rural BC, such as Masset, Queen Charlotte, Fraser Lake, Fort Nelson, Fort St James, Dease Lake, Fort St John, Dawson Creek, the Gulf Islands, and more! InReach works closely with the First Nations Health Authority, Island Health Authority and Northern Health Authority.


REFERENCES:

  1. Passer MW & Smith (2009). Chapter 8: Memory in Psychology: The Science of Mind and Behaviour 4th Ed. (pp.250-289). McGraw Hill

  2. Loprinzi PD, Day S, Hendry R, Hoffman S, Love A, Marable S, McKee E, Stec S, Watson H, Gilliland B. The Effects of Acute Exercise on Short- and Long-Term Memory: Considerations for the Timing of Exercise and Phases of Memory. Eur J Psychol. 2021 Feb 26;17(1):85-103. doi: 10.5964/ejop.2955. PMID: 33737976; PMCID: PMC7957845. Accessed Oct 25/22: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7957845/

  3. Labban JD, Etnier JL. The Effect of Acute Exercise on Encoding and Consolidation of Long-Term Memory. J Sport Exerc Psychol. 2018 Dec 1;40(6):336-342. doi: 10.1123/jsep.2018-0072. Epub 2018 Dec 12. PMID: 30541411. Accessed Oct 25/22: https://journals.humankinetics.com/view/journals/jsep/40/6/article-p336.xml

  4. Boraxbekk CJ, Salami A, Wåhlin A, Nyberg L. Physical activity over a decade modifies age-related decline in perfusion, gray matter volume, and functional connectivity of the posterior default-mode network-A multimodal approach. Neuroimage. 2016 May 1;131:133-41. doi: 10.1016/j.neuroimage.2015.12.010. Epub 2015 Dec 15. PMID: 26702778. Accessed Oct 25/22: https://pubmed.ncbi.nlm.nih.gov/26702778/

  5. Alzheimer Society of Canada (2022). About Dementia / What is dementia? Accessed Oct 25/22: https://alzheimer.ca/en/about-dementia/what-dementia

  6. Fried L & Columbia Mailman School of Public Health (Jun 10, 2021). Aging / Changes that occur to the aging brain: What happens when we get older. Accessed Oct 25/22: https://www.publichealth.columbia.edu/public-health-now/news/changes-occur-aging-brain-what-happens-when-we-get-older

  7. Alzheimer Society of Canada (2021 March). What is dementia (pdf handout). Accessed Oct 25/22: https://alzheimer.ca/sites/default/files/documents/ASC_What-is-dementia-info-sheet_en.pdf

  8. Alzheimer Society of Canada (2022). About dementia / Do I have dementia? / The differences between normal aging and dementia. Accessed Oct 25/22: https://alzheimer.ca/en/about-dementia/do-i-have-dementia/differences-between-normal-aging-dementia

  9. Alzheimer Society of Canada (2022). About dementia / What is Alzheimer’s disease / How Alzheimer’s disease changes the brain. Accessed Oct 25/22: https://alzheimer.ca/en/about-dementia/what-alzheimers-disease/how-alzheimers-disease-changes-brain

  10. Domingos C, Pêgo JM, Santos NC. Effects of physical activity on brain function and structure in older adults: A systematic review. Behav Brain Res. 2021 Mar 26;402:113061. doi: 10.1016/j.bbr.2020.113061. Epub 2020 Dec 24. PMID: 33359570. Accessed Oct 25/22: https://pubmed.ncbi.nlm.nih.gov/33359570/

  11. Northern Brain Injury Association (2022). Brain structure and function: The Structure and Function of the Human Brain. Accessed Oct 25/22: https://www.nbia.ca/brain-structure-function/

  12. Heart and Stroke Foundation of Canada (2022). Healthy Living / Stay Active / How much physical activity do you need? Accessed Oct 25/22: https://www.heartandstroke.ca/healthy-living/stay-active/how-much-physical-activity-do-you-need

  13. Public Health Agency of Canada. Physical Activity Tips for Adults (18-64 years): Tips to Get Active. Accessed Oct 25/22: https://www.canada.ca/content/dam/phac-aspc/migration/phac-aspc/hp-ps/hl-mvs/pa-ap/assets/pdfs/07paap-eng.pdf

  14. Canadian Society of Exercise Physiology. The Canadian 24-Hour Movement Guidelines for Adults (18-64): Make your whole day matter. Accessed Oct 25/22: https://csepguidelines.ca/guidelines/adults-18-64/

IMAGES:

Lost Key - illustrated by Susan Herdman, Oct 26/22.

Bike - https://pixabay.com/vectors/bicycle-wheel-bike-mountain-bike-757914/

Jogger - https://pixabay.com/vectors/exercising-jogging-trees-healthy-24419/

Normal vs Alzheimer's Brain - Engedeal, K & University of Oslo. (Apr 7, 22). standard_compressed_Alzheimer pic. Accessed Oct 26/22: https://sml.snl.no/Alzheimers_sykdom

Exercising Brain - https://pixabay.com/vectors/brain-organ-muscle-body-mind-5532459/

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