The Effects of Cardiovascular Exercise on Corticospinal Excitability in People with Subacute Stroke

Cardiovascular exercise (CE) shows promise for stroke recovery, partly by inducing neuroplasticity through excitatory neural signaling. While mechanisms are well-documented in animal models, the neurophysiological effects of CE in humans post-stroke--especially in the early subacute phase when the brain may be more responsive--remain unclear. In this study, 76 individuals within 3 months of their first-ever ischemic stroke were randomized to eight weeks of progressive CE using recumbent steppers plus standard care, or standard care alone. Corticospinal excitability (CSE) was assessed bilaterally using single and paired-pulse transcranial magnetic stimulation (TMS) at baseline, four weeks, and eight weeks. TMS was delivered at rest (chronic effect) and following a single high-intensity interval training (HIIT) session (acute effect). A single HIIT session at baseline significantly increased acute CSE in the contralesional hemisphere. However, despite significant improvements in cardiorespiratory fitness--indicating the effectiveness of the CE intervention--CE training did not lead to significant chronic or acute changes in CSE compared to standard care. This is the first study to investigate the effects of CE on CSE in early subacute stroke. Our findings indicate that while CE improves fitness levels during this critical period of recovery, it may have limited effects on CSE. Trial Registration: https://clinicaltrials.gov/study/NCT05076747.