... A number of investigations have attempted to identify mechanisms explaining the relationship between sleep loss and impaired exercise performance. Studies have explored changes to cardiorespiratory variables (e.g., V O 2peak [49,50,120,126,132], ventilation [41,49,93,110,120,126,132], heart rate [41,49,50,52,91,110,120,124,126,128,132,139], blood pressure [50]); perceived effort (measured via rating of perceived exertion) [41, 43, 44, 51, 52, 56, 57, 75, 86, 89-92, 95, 100, 110, 124, 132, 139]; muscle glycogen [91]; lactate [49,67,77,91,93,95,98,124,128,139]; catecholamines [67,121,126]; hormones (cortisol [43,55,63,67,75,84,127], testosterone [63,75,84,127], growth hormone [67], prolactin [67], melatonin [55], hepcidin [54], insulin [61]); body temperature (oral temperature [43,45,78,79,81,90,94,95,116] and core temperature [53,80,91,110]); immune function [44,50,54,62,127]; and neural drive [60,76,86,92]. However, it was not the intention of the present study to explore these mechanisms; rather our aim was to quantify the magnitude of effects that acute sleep loss has on exercise performance. ...