Abstract
Acute aerobic exercise has been demonstrated to increase corticospinal excitability (CSE), an important precursor to long-term neuroplasticity, and therefore, learning. However, while this effect has been demonstrated in recent research, the exact mechanism driving this response remains elusive. Furthermore, although overall trends in study data support an effect of aerobic exercise on the brain, there appears to be considerable variability between individuals. We sought to explore this variability by characterizing individual responses of participants to a single bout of aerobic exercise. Retrospective data analysis was conducted on individual participant data (N = 92) from four studies, all which used transcranial magnetic stimulation to assess CSE before and after an aerobic exercise intervention. Responses ranged from a -53% to an 854% change in CSE following exercise, with a positive change in CSE demonstrated following 57 sessions, while 35 sessions showed a negative change, and 22 yielded a negligible difference (defined as a change of less than +/-10%). While most studies examining the impacts of aerobic exercise on CSE have found significant increases at the group level, our findings demonstrate that these results are highly variable at the individual level. To date, the cause of this variability remains unknown, necessitating further investigation. Knowledge as to how and why individuals vary in their neurophysiological responses to exercise may reveal the mechanism(s) driving exercise-induced changes in CSE, which is critical in the use of exercise as a rehabilitative tool.
