Effects of Transcranial Direct Current Stimulation on Psychophysiological Responses to Maximal Incremental Exercise Test in Recreational Endurance Runners

Abstract

Previous studies have suggested that transcranial direct current stimulation (tDCS) might improve exercise performance and alter psychophysiological responses to exercise. However, it is presently unknown whether this simple technique has similar (or greater) effects on running performance. The purpose of this study was, therefore, to test the hypothesis that, compared with sham and cathodal tDCS, anodal tDCS applied over the M1 region would attenuate perception of effort, improve affective valence, and enhance exercise tolerance, regardless of changes in physiological responses, during maximal incremental exercise. In a double-blind, randomized, counterbalanced design, 13 healthy recreational endurance runners, aged 20–42 years, volunteered to participate in this study. On three separate occasions, the subjects performed an incremental ramp exercise test from rest to volitional exhaustion on a motor-driven treadmill following 20-min of brain stimulation with either placebo tDCS (sham) or real tDCS (cathodal and anodal). Breath-by-breath pulmonary gas exchange and ventilation and indices of muscle hemodynamics and oxygenation were collected continuously during the ramp exercise test. Ratings of perceived exertion (RPE) and affective valence in response to the ramp exercise test were also measured. Compared with sham, neither anodal tDCS nor cathodal tDCS altered the physiological responses to exercise (P > 0.05). Similarly, RPE and affective responses during the incremental ramp exercise test did not differ between the three experimental conditions at any time (P > 0.05). The exercise tolerance was also not significantly different following brain stimulation with either sham (533 ± 46 s) or real tDCS (anodal tDCS: 530 ± 44 s, and cathodal tDCS: 537 ± 40 s; P > 0.05). These results demonstrate that acute tDCS applied over the M1 region did not alter physiological responses, perceived exertion, affective valence, or exercise performance in recreational endurance runners.

Effects of Transcranial Direct Current Stimulation on Cycling Time Trial Performance and Prefrontal Cortex Activation

“…The major finding in this study was that 10km cycling time trial performance was unaffected by tDCS via the Halo Sport device. Results confirm some previous findings showing that tDCS has minimal effect on exercise performance and related physiological parameters [8,[23][24][25]. In addition, it was shown that both PFC and muscle oxygenation of the vastus lateralis were maintained over the entire portion of this self-paced, 10km time trial.…”

“…These results are similar to those of Park et al [14] who found no change in HR responses during a constant load treadmill test after 20 minutes of Halo stimulation. Additionally, there are various studies that found no changes in HR responses during different exercises tasks following tDCS [8,23,26]. However, results of studies investigating tDCS and exercise related cardiovascular responses are conflicting.…”

Transcranial Direct Current Stimulation Decreases the Decline of Speed during Repeated Sprinting in Basketball Athletes

“…Studies involving different types of exercise intervention, including swimming, running, and cycling have found that tDCS does not influence the heart rate during exercise [ 14 , 21 , 22 ]. Additionally, a double-blind, randomized, and counterbalanced study discovered that tDCS did not influence the postexercise perceived fatigue of trained long-distance runners [ 23 ]. Park et al found that tDCS improved performance in endurance exercise without influencing heart rate, RPE, or the metabolism index [ 14 ].…”

Neurostimulation, doping, and the spirit of sport

“…Similarly applying anodal tDCS to the temporal cortex (but prior to 20-km cycling time trial rather than a maximal incremental cycling task), Barwood et al [56] did not find any improvements in power output or cycling performance. Furthermore, Baldari et al [57] did not find any improvement in physiological responses (including heart rate, pulmonary ventilation, and VO2 max ), perceived exertion, affective valence, or exercise performance in recreational runners on a maximal incremental running test following anodal tDCS to the primary motor cortex. In contrast Vitor-Costa et al, [58] found an improvement in submaximal exercise tolerance in physically active subjects on a cycling task following anodal tDCS to the primary motor cortex, but this was not accompanied by changes to evaluated physiological or perceptual parameters of the sort observed in Okano's study, including the subject's heart rate and RPE.…”