Intensity-dependent effects of cycling exercise on corticospinal excitability in healthy humans: a pilot study

Abstract

-Aims: the aim of this study was to verify the effects of different intensities of locomotor exercise on corticospinal excitability. Methods: 18 healthy subjects (27.6 ± 6.5 years,) participated in a design study of three different exercise protocols on a cycle ergometer: (i) 10 min at 75% Wmax (high intensity); (ii) 15min at 60% Wmax (moderate intensity) or (iii) 30 min at 45% Wmax (low intensity). The protocols of lower body cycling were assigned in random order in separate sessions. A control session was done with subjects at rest. Corticospinal excitability was assessed before (baseline) and every 5 min for 15min after the end of exercise/rest (time: 0, 5, 10 and 15) by measurement of the motor evoked potential (MEP) elicited by transcranial magnetic stimulation in the relaxed first-dorsal interosseus muscle. Results: Compared to the resting session, a significant decrease (64%) in the motor evoked potential amplitudes was found only in the session of exercise of high intensity. This result seems depend on the level of physical activity of subject. No change was found after rest, low and moderate exercises. Conclusions: These findings suggest that changes in the corticospinal excitability depend on exercise intensity and level of physical activity of subjects.

Aerobic exercise and aerobic fitness level do not modify motor learning

“…At the cortical level, a single session of aerobic exercise increases corticospinal tract excitability (CSE) and reduces GABA A inhibition in the motor cortex, both of which are associated with improvements in motor skill retention 10 , 17 . However, individuals who are inactive or have low physical activity levels do not have changes in CSE after a single session of aerobic exercise compared to those with high physical activity levels 25 , 26 . Therefore, individuals with different aerobic fitness levels may have variable neuroplasticity-related responses to aerobic exercise (e.g., changes in neurochemical release or CSE), and thus, have different motor learning outcomes after aerobic exercise.…”