Gender differences in sweat lactate

Sweat rate may affect sweat lactate concentration. The current study examin ed potential gender differences in sweat lactate concentrations because of varying sweat rates. Males (n = 6) and females (n = 6) of similar age, perc entage body fat, and maximal oxygen consumption (VO2max) completed constant load (CON) cycling (30 min - approximately 40% VO2max) and interval cyclin g (INT) (15 1-min intervals each separated by I min of rest) trials at 32 ( 1) degrees C wet bulb globe temperature (WBGT). Trials were preceded by 15 min of warm-up (0.5 kp, 60 rpms) and followed by 15 min of rest. Blood and sweat samples were collected at 15, 25, 35, 45. and 60 min during each tria l. Total body water loss was used to calculate sweat rate. Blood lactate co ncentrations (CON congruent to 2 mmol . l(-1). INT congruent to 6 mmol . l( -1)) and sweat lactate concentrations (CON and INT congruent to 12 mmol . l (-1)) were not significantly different (P > 0.05) at any time between gende rs for CON or INT. Overall sweat rates (ml . h(-1)) were not significantly different (P > 0.05) between trials but were significantly greater(P less t han or equal to 0.05) for males than for females for CON [779.7 (292.6) ver sus 450.3 (84.6) ml . h(-1)] and INT [798.0 (268.3) versus 503.0 (41.4) ml h(-1)]. However, correcting for surface area diminished the difference [CON : 390.7 (134.4) versus 277.7 (44.4) ml . h(-1). INT: 401.5 (124.1) versus 3 10.6 (23.4) ml h(-1) (P less than or equal to 0.07)]. Estimated total lacta te secretion was significantly greater(P less than or equal to 0.05) in mal es for CON and INT. Results suggest that sweat rate differences do not affe ct sweat lactate concentrations between genders.