Brain stimulation modulates the autonomic nervous system, rating of perceived exertion and performance during maximal exercise
British Journal of Sports Medicine
Physical Education Department, Federal University of Rio Grande Do Norte (UFRN), Natal, Rio Grande do Norte, Brazil; Department of Neurology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil; Physical Education and Sports Institute, Rio de Janeiro State University (UERJ), Rio de Janeiro, RJ, Brazil; Center of Physical Education and Sport, State University of Londrina (UEL), Londrina, Parana, Brazil; Department of Biomedical Engineering, City College of New York of CUNY, New York, New York, United States; MRC/UCT Research Unit for Exercise Science and Sports Medicine, University of Cape Town (UCT), Cape Town, Western Cape, South Africa
Background The temporal and insular cortex (TC, IC) have been associated with autonomic nervous system (ANS) control and the awareness of emotional feelings from the body. Evidence shows that the ANS and rating of perceived exertion (RPE) regulate exercise performance. Non-invasive brain stimulation can modulate the cortical area directly beneath the electrode related to ANS and RPE, but it could also affect subcortical areas by connection within the corticocortical neural networks. This study evaluated the effects of transcranial direct current stimulation (tDCS) over the TC on the ANS, RPE and performance during a maximal dynamic exercise. Methods Ten trained cyclists participated in this study (33±9 years; 171.5±5.8 cm; 72.8±9.5 kg; 10-11 training years). After 20-min of receiving either anodal tDCS applied over the left TC (T3) or sham stimulation, subjects completed a maximal incremental cycling exercise test. RPE, heart rate (HR) and R-R intervals (as a measure of ANS function) were recorded continuously throughout the tests. Peak power output (PPO) was recorded at the end of the tests. Results With anodal tDCS, PPO improved by ~4% (anodal tDCS: 313.2±29.9 vs 301.0±19.8 watts: sham tDCS; p=0.043), parasympathetic vagal withdrawal was delayed (anodal tDCS: 147.5±53.3 vs 125.0±35.4 watts: sham tDCS; p=0.041) and HR was reduced at submaximal workloads. RPE also increased more slowly during exercise following anodal tDCS application, but maximal RPE and HR values were not affected by cortical stimulation. Conclusions The findings suggest that non-invasive brain stimulation over the TC modulates the ANS activity and the sensory perception of effort and exercise performance, indicating that the brain plays a crucial role in the exercise performance regulation.