Effects of bilateral dorsolateral prefrontal cortex high-definition transcranial direct-current stimulation on time-trial performance in cyclists with type 1 diabetes mellitus.

ABSTRACT

BACKGROUND: HD-tDCS is capable to increase the focality of neuromodulation and has been recently applied to improve endurance performance in healthy subjects. OBJECTIVE/HYPOTHESIS: Whether these putative advantages could be exploited in active subjects with type 1 diabetes mellitus (T1D) remains questionable. METHODS: In a double-blind, randomized crossover order, 11 high-level cyclists (27 ± 4.3 years; weight 65.5 ± 8.6 kg; height 180 ± 8 cm; VO2peak 67.5 ± 2.9 mL min-1 kg-1) with T1D underwent either HD-tDCS (F3, F4) or control (SHAM) and completed a constant-load trial (CLT) at 75% of the 2nd ventilatory threshold plus a 15-km cycling time-trial (TT). RESULTS: After HD-tDCS, the total time to cover the TT was 3.8% faster (P < 0.01), associated with a higher mean power output (P < 0.01), and a higher rate of power/perception of effort (P < 0.01) and power/heart rate at iso-time (P < 0.05) than the SHAM condition. Physiological parameters during CLT and TT did not differ in both conditions. CONCLUSIONS: These findings suggest that upregulation of the prefrontal cortex could enhance endurance performance in high-level cyclists with T1D, without altering physiological and perceptual responses at moderate intensity. Present data open to future applications of HD-tDCS to a wider population of active T1D-subjects.