UBC Theses and Dissertations
The impact of an acute bout of high intensity exercise on corticospinal excitability and transcallosal inhibition in older adults Chau, Briana
While studies have investigated the effect of exercise on corticospinal, intracortical, and interhemispheric processes in young adults, few studies have focused on older adults. Current evidence supports the hypothesis that there is a shift from predominantly inhibitory to excitatory interhemispheric interactions as we age. Other work suggests that changes observed in transcallosal inhibition (TCI) with age (i.e., reduced ipsilateral silent period (iSP) duration and area) may be mitigated by physical activity. Therefore, the main purpose of this experiment was to advance understanding of how an acute bout of high intensity exercise alters patterns of corticospinal and interhemispheric excitability in the healthy older adult population. 41 healthy older adults participated in this study. Participants were randomized into the exercise (n=21) or the rest (n=20) group. Participants in the exercise group completed an acute bout of high intensity exercise on a recumbent bike lasting 23 minutes. Participants in the rest group sat for the same duration of time while their attention was controlled by watching a nature documentary. Corticospinal excitability and TCI of the upper limbs was assessed via transcranial magnetic stimulation before (baseline), immediately (Post 1), and 30 minutes (Post 2) following high intensity exercise or rest. Results indicated that there was an increase in corticospinal excitability immediately and 30 minutes post exercise in the dominant hemisphere. There was also an interaction effect between timepoint and hemisphere in transcallosal inhibition. The current study showed following an acute bout of high intensity exercise, there was an increase in corticospinal excitability in the dominant hemisphere and a hemispheric difference in TCI in older adults. The present research provides insight on how exercise could be used to mitigate age related changes in the brain and informs how exercise therapies could be employed in association with rehabilitation in clinical populations.
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