The Effects of Aerobic Exercise on Brain Function in Older Adults

Background: As most of us know, the human brain deteriorates with age and results in cognitive decline. Often, older adults end up with dementia or Alzheimer’s Disease. They lose the ability to remember things, solve problems, plan, and even move efficiently. The aging brain presents problems within our society such as medical expenses, decreased ability to work, increases in family member/ caregiver stress, etc. Although no cure has been found for this devastating health issue, lifestyle factors such as regularly engaging in physical activity may prevent or inhibit the negative effects of age on the human brain.

Research on the effects of exercise and cognition began in the 1930s and primarily looked at the effects of physical activity on reaction time (The amount of time it takes for the body to respond to a stimulus)(Hillman et al.,2008). They used reaction time as a measurement of cognition because they did not have the technology that they do now such as fMRIs and ERPs (Event related brain potentials…measures the brain’s response to a cognitive or motor event and allows us to relate a certain event to a certain brain area).  Although reaction time is one good way of looking at how the brain is performing, it is only looking at one process of the brain. Current research focuses mostly on the following types of processes of the brain:

  • Speed: Reaction time, finger tapping…How fast the human body can respond to a stimulus.
  • Visuospatial Tasks: How someone perceives objects and spatial relationships between one’s self or other objects and the environment
  • Controlled-Processing Tasks: Tasks that require controlled, effortful processing… Things that people really have to focus on…ex: patting your head and rubbing your stomach at the same time, playing an instrument, etc.
  • Executive-Control Tasks: Tasks that do not become automatic over time and require constant mediation by a central executor… Involves coordination, inhibition, scheduling, abstract thinking, planning, and working memory tasks. Ex: The Stroop test

Now that you have a bit of background of the brain, let’s go into further detail about it’s relationship with aerobic exercise and aging.

Recent Research: There has been some mixed evidence regarding the positive effects of aerobic exercise on cognitive decline in older adults, however the studies showing little or no improvement in cognition are generally characterized by poor methodology such as working at too low of an intensity (Colcombe & Kramer, 2003). However, some studies show improvement in reaction time even in low to moderate intensities (Kamijo et al., 2009) and there is an overwhelming amount of evidence supporting the idea that aerobic exercise does in fact improve cognition in older adults (Acevedo et al., 2007; Baker et al., 2010; Colcombe et al., 2006).

The first study I will be going into detail with was conducted in 2003 by Colcombe & Kramer. They performed a meta-analysis on 18 different studies that looked at the effects of aerobic exercise on the brain.  They found that exercise had an overall significant moderate effect on cognition (ES=0.478).  Interestingly, they found that aerobic exercise had the best effects on executive processes, mid-old age people (66-70 years old), and females. They also found that aerobic exercise worked the best when combined with resistance training, consisted of moderate session duration (31-45 minutes), and when engaged in for 6+ months. Though, aerobic exercise alone did have significant effects as well as males, other age groups and other durations of training. You can see more of their results in the following tables:

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Another article worth noting is a review by Hillman & colleagues (2008). They reviewed several important metas on the topic of the effects of exercise on cognition. Some of their important findings included:

  • There were no detrimental effects from exercise
  • Increased aerobic fitness was associated with cognition benefits
  • Higher BMIs had a negative correlation on cognition
  • Exercise activates the same parts of the brain that are activated when engaging in mathematics and reading such as the frontoparietal network
  • Exercise resulted in greater academic achievement in kids also

I find it interesting that physicians do not typically recommend aerobic exercise for patients with dementia or other cognitive impairments (given the amount of evidence showing improvement in cognition and other positive health benefits associated with exercise), yet they are quick to prescribe pharmaceuticals to relieve symptoms (which will not necessarily improve their cognitive performance and are associated with negative side effects). Maybe I am out of line here and need to further educate myself on the effects of pharmaceuticals on cognition, but I don’t believe they should kick the bucket on exploring the idea of utilizing exercise for cognition improvement in older adults. Feel free to question or comment below!

Acevedo, A., & Loewenstein, D. A. (2007). Nonpharmacological cognitive interventions in aging and dementia. Journal of Geriatric Psychiatry and Neurology, 20(4), 239-249.

Baker, L. D., Frank, L. L., Foster-Schubert, K., Green, P. S., Wilkinson, C. W., McTiernan, A., . . . Craft, S. (2010). Aerobic exercise improves cognition for older adults with glucose intolerance, a risk factor for alzheimer’s disease. Journal of Alzheimer’s Disease : JAD, 22(2), 569.

Colcombe, S., & Kramer, A. F. (2003). Fitness effects on the cognitive function of older adults: A meta-analytic study. Psychological Science, 14(2), 125-130.

Colcombe, S. J., Erickson, K. I., Scalf, P. E., Kim, J. S., Prakash, R., McAuley, E., . . . Kramer, A. F. (2006). Aerobic exercise training increases brain volume in aging humans. The Journals of Gerontology.Series A, Biological Sciences and Medical Sciences, 61(11), 1166.

Hillman, C. H., Erickson, K. I., & Kramer, A. F. (2008). Science and society: Be smart, exercise your heart: Exercise effects on brain and cognition. Nature Reviews: Neuroscience, 9(1), 58-65. 

Kamijo, K., Hayashi, Y., Sakai, T., Yahiro, T., Tanaka, K., & Nishihira, Y. (2009). Acute effects of aerobic exercise on cognitive function in older adults. Journals of Gerontology: Series B, 64B(3), 356-363.

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