Effects of twelve weeks' aerobic training on motor cortex excitability.

Background: Regular physical activity or aerobic exercise is well known to increase brain plasticity. Recent studies have reported that aerobic exercise enhances neuroplasticity and motor learning. The aim of this study was to investigate if 12 weeks' aerobic training can modify cortical excitability and motor evoked potential (MEP) responses.

Methods: Fifteen untrained males were recruited. Cortical excitability was investigated using TMS. VO2max was estimated using Cooper's test. Aerobic intervention lasted 12 weeks. The subjects performed a 6-week supervised aerobic workout, 3 times a week, at 60-75% of their maximum heart rate (HRmax). Over the following 6 weeks, they performed a supervised aerobic workout 3 times a week at 70-75% of FCmax.

Results: After 8 weeks of aerobic training there was a significant increase of distance covered during Cooper's test (P<0.001) and a significant increase of VO2max (P<0.001); there was also an improvement in resting motor threshold (rMT decreased from 60.5±6.6% [T0] to 55.8±5.9% [T2]; P<0.001), motor evoked potential latency decreased (from 25.3±0.8 ms [T0] to 24.1±0.8 ms [T2]; P<0.001), and motor evoked potential amplitude increased (from 0.58±0.09 mV [T0] to 0.65±0.08 mV [T2]; P<0.001). Furthermore, after 12 weeks' aerobic training there were improvements in all parameters.

Conclusions: This study shows that aerobic activity seems to induce changes in cortical excitability if performed for a period longer than 4 weeks, in addition to typical cardiorespiratory benefits in previously untrained males.