Effort perception and endurance running performance following prefrontal transcranial direct current stimulation (tDCS): a randomized crossover-controlled trial

The ergogenic potential of stimulating the prefrontal cortex with transcranial direct current stimulation (tDCS) for running endurance remains unclear. This randomized, sham-controlled crossover trial evaluated the effects of bilateral dorsolateral prefrontal cortex (DLPFC) tDCS on running time to exhaustion (TTE) and ratings of perceived exertion (RPE) in endurance-trained men. Fifty-three participants (age: 22 ± 2 years; maximal oxygen consumption: 50.3 ± 6.4 mL/min/kg) completed two stimulation sessions in randomized order, separated by one week: 20 min of active or sham multichannel tDCS (2 anodes, 6 return electrodes) targeting the DLPFC bilaterally. Each session was followed by a treadmill constant-load test at 90% of maximal aerobic speed until exhaustion, with oxygen consumption (VO2), heart rate (HR), blood lactate, and RPE monitored throughout. TTE did not differ between active and sham stimulation. Likewise, RPE, VO2, HR, and blood lactate were comparable between conditions. Including an additional no-tDCS control session in 40 participants did not alter these results. A single session of bilateral DLPFC tDCS did not influence perceived exertion or endurance performance in endurance-trained men. These findings underscore the need for large multi-session trials incorporating both physiological and perceptual outcomes to clarify the ergogenic potential of prefrontal stimulation in endurance-trained athletes.