Discussion
hypoxia, sports-related
HYPOXIC, HYPOXIA, CORTEX
To the best of our knowledge, this work is the first to examine the effects of anodal-tDCS over the M1 and DLPFC areas on endurance performance, cognitive function, and psychophysiological responses under hypoxic conditions. As a novel finding, we observed that the participants had a significantly longer TTE under hypoxia (OIt is widely known that hypoxia can negatively impact both cognitive function and physical performance (especially endurance performance) through both central and peripheral processes [The two-dimension Circumplex Model of Affect under 3 experimental conditions. The mean value of affective response and felt arousal (FA) were used to create a two-dimension circumplex model of affect during the endurance cycling task in hypoxia after transcranial direct current stimulation targeting the motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), and sham conditions. Previous research has suggested that the PFC, including the DLPFC, ventromedial, and ventrolateral PFC, regulates exercise performance through higher order processing of interoceptive cues (i.e., afferent feedbacks), emotional and psychological drive (e.g., internal and external motivation, RPE, environmental features, among others), and decision making (i.e., increase/decrease pace or stop exercise) [The DLPFC tDCS condition also produced more positive psychophysiological responses than the sham condition in the current study. It is worth noting that in a hypoxic environment, OThe current study also found no difference in the amplitude of EMG of the VL and RF muscles during a cycling endurance task under hypoxia between tDCS conditions. In contrast, only after DLPFC tDCS was the amplitude of EMG of the VM muscle significantly higher than sham. The causative effect of tDCS on muscle EMG has been a contentious topic because most studies found no effect of tDCS on muscle EMG [Our results also showed that despite a higher CWST score in the DLPFC tDCS condition (ΔIn this context, Ochi et al. [Finally, an important consideration regarding the current study's findings is the fact that, contrary to some previous studies, there was no significant positive effect of M1 tDCS on endurance and cognitive performance, and psychophysiological responses to exercise in hypoxia. This is in line with a recent study by Machado et al. [The lack of use of TMS for hot spotting the lower limb representation in the M1, which could provide a more precise target for tDCS, and the lack of neurophysiological/neuroimaging measures that could provide more information about changes in brain activity are the study's limitations. Finally, to the best of our knowledge, this is the first study to investigate the effect of tDCS on a variety of sports-related variables in hypoxia, and as a result, we were confronted with a lack of information regarding the study's design as well as discussing our findings with more mechanistic interpretations. On the other hand, this is the first study not only to assess the effect of tDCS on endurance exercise in hypoxia but also the first to directly compare two tDCS montages targeting different brain regions on whole-body exercise performance. Radel et al. [