Article Text
Abstract
Fatigue occurs prematurely during exercise in hot conditions. The role of thermal perception in driving pacing has yet to be determined. We tested the hypothesis that improved thermal perception (feeling cooler and more comfortable) in the absence of changed thermal state, would alter pacing and improve time trial (TT) performance. Eleven trained cyclists (mean(sd):age 30 (8) y; height 1.78 (0.06) m; mass 76.0 (8.3) kg) completed three 40 km TTs in standardised conditions (32°C, 50%RH) with thermal perception altered prior to one TT using cold-receptor-activating menthol spray (0.05% MENTHOL and surfactants) in contrast to a control spray (CS; surfactants only) and no spray control (CON). Perceptual responses (thermal comfort, sensation and perceived exertion), thermal responses (skin and rectal temperature) and performance (power output, time to completion) were measured. Data were compared within participant between trials using repeated measures ANOVA with α level for statistical tests of 0.05. MENTHOL improved thermal perception prior to and during exercise up to 15 km compared to CS and CON. There was no difference in the pacing strategy adopted as a consequence of the altered thermal perception (5 km ‘bins' or the first 1 km of each TT up to 10 km) despite a difference in skin temperature profile at the start of exercise (CS 33.3 (1.1)°C and MENTHOL 33.4 (0.4)°C cp CON 34.5 (0.5)°C). There was no performance benefit in the MENTHOL condition; TT completion time CON: 71.58 (6.21) min, CS: 70.94 (6.06) min, MENTHOL 71.04 (5.47) min. RPE was not different between trials at any stage. Thermal perception is not a primary driver of pacing at the start of exercise or during cycling in hot conditions. Prior to reaching a threshold for thermal perceptual disturbance pacing strategy may be subconsciously regulated in accordance with RPE. MENTHOL spray did not enhance initial TT performance in the conditions of the present study.