Brain activity during self-paced vs. fixed protocols in graded exercise testing.

Electroencephalography research surrounding maximal exercise testing has been limited to male subjects. Additionally, studies have used open-looped protocols, meaning individuals do not know the exercise endpoint. Closed-loop protocols are often shown to result in optimal performance as self-pacing is permitted. The purpose of this study was to compare brain activity during open- and closed-loop maximal exercise protocols, and to determine if any sex differences are present. Twenty-seven subjects (12 males, ages 22.0 ± 2.5 years) participated in this study. A pre-assembled EEG sensor strip was used to collect brain activity from specific electrodes (F3/F4: dorsolateral prefrontal cortex, or dlPFC; and C3/Cz/C4: motor cortex, or MC). Alpha (8-12 Hz) and beta (12-30 Hz) frequency bands were analyzed. Subjects completed two maximal exercise tests on a cycle ergometer, separated by at least 48 h: a traditional, open-loop graded exercise test (GXT) and a closed-loop self-paced VO2max (SPV) test. Mixed model ANOVAs were performed to compare power spectral density (PSD) between test protocols and sexes. A significant interaction of time and sex was shown in the dlPFC for males, during the GXT only (p = 001), where a peak was reached and then a decrease was shown. A continuous increase was shown in the SPV. Sex differences in brain activity during exercise could be associated with inhibitory control, which is a function of the dlPFC. Knowledge of an exercise endpoint could be influential towards cessation of exercise and changes in cortical brain activity.

Transcranial Direct Current Stimulation with the Halo Sport Does Not Improve Performance on a Three-Minute, High Intensity Cycling Test.

Transcranial direct current stimulation (tDCS) uses a weak electrical current that is sent through the cerebral cortex. The Halo Sport headphones are a user-friendly form of tDCS that is implemented by many athletes purportedly to improve performance. The purpose of this study was to determine the effect of tDCS, using the Halo Sport, on performance variables associated with a high-intensity three-minute cycling test. Eighteen healthy, active individuals (ten men, eight women) volunteered for this study. The Halo Sport headphones were worn during a 20-minute warmup before completing a high-intensity three-minute cycling test. A sham treatment was used in addition to the experimental condition. Ratings of perceived exertion (RPE) were assessed every 30 seconds and electromyography (EMG) of the quadriceps muscle group was measured throughout testing. Two-way repeated measures ANOVAs were used to determine the effect of condition and time on mean RPE, heart rate (HR) and power; paired samples t-tests were also used to compare conditions. Mean HR was higher in the experimental condition (p = 0.038). Otherwise, there were no differences between conditions on any of the variables (mean RPE, cadence and speed, mean and peak HR, power, root mean square EMG). Despite the popularity of this new device, our findings do not support an ergogenic effect. However, further research is warranted.