Exercise in the Elderly: BDNF and Executive Function

Exercise promotes cognitive function in children, adults and elderly individuals.

The mechanism for this effect is unclear. Some of the effect may be due to a general improvement in vascular function and health.

Another potential mechanism is via increased neuroplasticity mediated by neurotrophic factors.

Brain-derived neurotrophic factor (BNDF) is a known contributor to brain neuroplasticity. Levels of BNDF can be determined with serum assays.

RL Leckie and colleagues recently found support for BNDF mediation in an exercise in an interventional study with an elderly population.

The key elements of the design for their study included the following elements.

• Participants: Adults between the ages of 55 and 80
• Exercise intervention: Daily supervised walking sessions beginning with 10 minutes increasing to 40 minutes. Control intervention included stretching and toning sessions lead by an exercise professional
• Cognitive assessment: Task-switching paradigm commonly used to assess executive function
• Blood assay: Serum brain-derived neurotropic factor (BNDF) levels and BDNF genotype
• Statistical analysis: Multivariate linear regression analysis with key dependent variable being cognitive performance after one year of intervention

The main findings from the study included:

• Serum BDNF increased in the exercise group
• This effect was limited to primarily the participants over 70 years of age
• Enhanced executive function following exercise was demonstrated in those over 70
• BDNF level increases in the over 70 age group correlated with cognitive performance

The authors note their does not mean exercise is not important for cognitive function in the younger age group (55-70 years of age). Their study only highlights the age interaction with BDNF in moderating a single executive function task.

BDNF levels decrease with age and the level of decrease in BDNF correlates with reduction in volume of the brain hippocampus. The hippocampus plays a key role in memory function and in decline in memory associated with aging.

It is quite possible that regular exercise after age 70 reduces the age related effect on cognition moderated by BDNF.

Readers with more interest in this study can access the free full text manuscript by clicking on the PMID link in the citation below.

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Leckie RL, Oberlin LE, Voss MW, Prakash RS, Szabo-Reed A, Chaddock-Heyman L, Phillips SM, Gothe NP, Mailey E, Vieira-Potter VJ, Martin SA, Pence BD, Lin M, Parasuraman R, Greenwood PM, Fryxell KJ, Woods JA, McAuley E, Kramer AF, & Erickson KI (2014). BDNF mediates improvements in executive function following a 1-year exercise intervention. Frontiers in human neuroscience, 8 PMID: 25566019