Acute High-Intensity Interval Exercise Modulates Corticospinal Excitability in Older Adults

Abstract

Introduction: Acute exercise can modulate the excitability of the nonexercised upper limb representation in the primary motor cortex (M1). Measures of M1 excitability using transcranial magnetic stimulation (TMS) are modulated after various forms of acute exercise in young adults, including high-intensity interval training (HIIT). However, the impact of HIIT on M1 excitability in older adults is currently unknown. Therefore, the purpose of the current study was to investigate the effects of lower limb cycling HIIT on bilateral upper limb M1 excitability in older adults. Methods: We assessed the impact of acute lower limb HIIT or rest on bilateral corticospinal excitability, intracortical inhibition and facilitation, and interhemispheric inhibition of the nonexercised upper limb muscle in healthy older adults (mean age 66 ± 8 yr). We used single and pairedpulse TMS to assess motor evoked potentials, short-interval intracortical inhibition, intracortical facilitation, and the ipsilateral silent period. Two groups of healthy older adults completed either HIIT exercise or seated rest for 23 min, with TMS measures performed before (T0), immediately after (T1), and 30 min after (T2) HIIT/rest. Results: Motor evoked potentials were significantly increased after HIIT exercise at T2 compared with T0 in the dominant upper limb. Contrary to our hypothesis, we did not find any significant change in short-interval intracortical inhibition, intracortical facilitation, or ipsilateral silent period after HIIT. Conclusions: Our findings demonstrate that corticospinal excitability of the nonexercised upper limb is increased after HIIT in healthy older adults. Our results indicate that acute HIIT exercise impacts corticospinal excitability in older adults, without affecting intracortical or interhemispheric circuitry. These findings have implications for the development of exercise strategies to potentiate neuroplasticity in healthy older and clinical populations.

A Systematic Review on the Effects of Acute Aerobic Exercise on Neurophysiological, Molecular, and Behavioral Measures in Chronic Stroke

“…Findings from recent work on acute exercise in elderly adults may extend to those with stroke, as concomitant aging influences may affect the responses of the M1 to exercise. 61 Taken together, all these factors may have accounted for the mixed findings with respect to the directionality of AE induced effects on TMS.…”

Hippocampal blood flow rapidly and preferentially increases after a bout of moderate-intensity exercise in older adults with poor cerebrovascular health

“…Interestingly, post-exercise hippocampal blood flow never increased above baseline levels in individuals with high perfusion ( Figure 3 ). As we only tested a single type of exercise, it is possible that a different type of exercise stimulus, for example high intensity interval training, may elicit more robust vascular and neural plasticity in these individuals (Boyne et al, 2019; Kaiser et al, 2022; Neva et al, 2022; Weston et al, 2022). The present results provide preliminary evidence for the use of baseline cerebrovascular perfusion as a predictive biomarker for brain health benefit from exercise in aging populations.…”

Improved cognitive-motor processing speed and decreased functional connectivity after high intensity aerobic exercise in individuals with chronic stroke

“…Exercise improves processing speed after stroke 7 with stroke. Data reported here are a subset of the larger study (Greeley et al, 2021;Neva et al, 2022).…”

“…The data in this manuscript come from a large study on the impact of exercise on behaviour, brain function, and physiology in individuals with stroke. The data reported here are a subset of the larger study (Greeley et al, 2021(Greeley et al, , 2023Neva et al, 2022).…”