The purpose of this study was to assess the impact of sodium citrate (CIT) ingestion (600 mg·kg-1) during recovery from dehydrating cycling exercise (DE) on subsequent 40-km cycling performance in a warm environment (32 °C). Twenty male nonheat-acclimated endurance athletes exercised in the heat until 4% body mass (BM) loss occurred. After 16 h recovery with consumption of water ad libitum and prescribed diet (evening meal 20 kcal·kg-1, breakfast 12 kcal·kg-1) supplemented in a double-blind, randomized, crossover manner with CIT or placebo (PLC), they performed 40-km time-trial (TT) on a cycle ergometer in a warm environment. During recovery greater increases in BM and plasma volume (PV) concomitant with greater water intake and retention occurred in the CIT trial compared with the PLC trial (p < 0.0001). During TT there was greater water intake and smaller BM loss in the CIT trial than in the PLC trial (p < 0.05) with no between-trial differences (p > 0.05) in sweat loss, PV decrement, ratings of perceived exertion, or TT time (CIT 68.10 ± 3.28 min, PLC 68.11 ± 2.87 min). At the end of TT blood lactate concentration was higher (7.58 ± 2.44 mmol·L-1 vs 5.58 ± 1.32 mmol·L-1; p = 0.0002) and rectal temperature lower (39.54 ± 0.50 °C vs 39.65 ± 0.52 °C; p = 0.033) in the CIT trial than in the PLC trial. Compared with pre-DE time point, PV had decreased to a lower level in the PLC trial than in the CIT trial (p = 0.0001). In conclusion, CIT enhances rehydration after exercise-induced dehydration but has no impact on subsequent 40-km cycling TT performance in a warm uncompensable environment.
Keywords: core temperature; effort perçu; perceived exertion; plasma volume; rétention d’eau; température centrale; volume plasmatique; water retention.