Measuring the acute effects of two aerobic exercise training methods on cortical excitability in people with chronic stroke

Abstract

Background: Aerobic exercise (AE) upregulates neurotrophins and alters brain excitability post-stroke. Using transcranial magnetic stimulation (TMS) we compared the acute effects of moderate intensity continuous exercise (MICE) versus high intensity interval training (HIIT) on cortical excitability in patients with chronic stroke. Methods: Participants completed 25 min MICE (60 % VO₂ max) and HIIT (80 % VO₂ max / 40 % VO2 max), one week apart, matched for workload. Before and after exercise, subjects underwent neuronavigated TMS (figure of eight coil) followed by testing of pinch, grip strength and dexterity. Results: Short interval intracortical inhibition (SICI) decreased in the less affected hemisphere following MICE (22.03 % (11.14) to 30.5 % (20.63), p = 0.04), while there was no change following HIIT (25.22 % (14.97) to 32.19 % (22.04) (p=0.186). Pinch strength in the affected hand was also significantly lower following MICE. Conclusion: MICE may be superior to HIIT in acutely influencing neural networks of a non-exercised muscle.