Exercise and executive function in older adults: exploring the mechanisms

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Alexis B. Slutsky (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Jennifer Etnier

Abstract: Exercise is beneficial to cognitive performance and to executive function (EF) in particular, however the underlying mechanisms as to how exercise yields these benefits are not clear. The overall purpose of this study was to identify the extent to which a single bout of exercise affects EF in older adults and to gain an understanding of the role of biological factors such as vagal tone, brain-derived neurotrophic factor (BDNF), and the hemodynamic response in neural tissues (i.e. neural activation patterns) in this relationship. Vagal tone, a measure of parasympathetic nervous system activity, shares an intimate relationship with EF in adults; higher resting vagal tone is associated with better EF and increased vagal tone following exercise training is associated with improved EF. Interestingly, BDNF and neural activation patterns respond to acute exercise and are related to both vagal tone and EF in older adults. As such we investigated BDNF and neural activation as mechanisms in the relationship of acute exercise and EF in older adults with vagal tone as a potential moderator. Participants were sixteen healthy, older adults (M=72.3 years) from the community. Day one testing consisted of an assessment of resting heart rate, EF testing (inhibitory control, set shifting, and working memory), a blood draw, and a submaximal exercise test. Days two and three were counterbalanced for condition (exercise or rest) and included a pre-condition blood draw, exercise or rest, a post-condition blood draw, and post-condition EF testing (same as baseline) during a functional magnetic resonance imaging (fMRI) scan. The exercise condition included cycling at 55-65% Heart Rate Reserve for 30 minutes and the rest condition consisted of sitting on the bike for 30 minutes at rest. Paired samples t-tests assessed the effects of condition on EF, BDNF, and neural activation. Linear regressions were used to assess the relationships between change in BDNF and change in neural activation with change in EF. A median split was performed on vagal tone (root mean square of the successive differences; RMSSD) and independent samples t-tests assessed the difference between high and low vagal tone groups on change in BDNF, change in neural activation, and change in EF. There was no overall effect of condition on change in EF or change in BDNF, however change in BDNF following exercise, relative to following rest, predicted change in set shifting. There were significant differences in neural activation following exercise, compared to rest, and change in neural activation was associated with EF. Interestingly, those with higher vagal tone had greater benefits from exercise as compared to those with lower vagal tone as assessed using measures of EF, BDNF, and neural activation. These findings provide initial evidence of mechanisms involved in the relationship of acute exercise and EF in older adults. Of importance, we identified vagal tone as a moderator that helps to account for some individual variability in the response to exercise. Larger studies are needed to test these preliminary relationships in a moderated-mediation model.

Additional Information

Language: English
Date: 2019
Aging, BDNF, Executive function, Exercise, FMRI, Heart rate variability
Exercise for older people
Executive functions (Neuropsychology)
Magnetic resonance imaging
Heart rate monitoring

Email this document to