Abstract
We investigated whether heat adaptation (HA) could be maintained in trained females following an initial acclimation period. The experimental group (EXP, n = 11) completed 10 sessions of HA over 2 weeks, followed by nine sessions of HA maintenance (HA(M)) over 3 weeks. HA was induced with home-based stationary cycling while overdressing. A control group (CON, n = 4) was exposed to heart rate-matched thermoneutral training. Prior to and at the end of the acclimation period (PRE, MID) and following the maintenance period (POST), V̇O2max , peak power output (PPO), and hemoglobin mass (Hb(mass)) were determined in 18°C, before a 20 km time trial (TT) in 35°C, 45% RH. During the TT, rectal and mean skin temperature (T(re), T¯ (sk)), heart rate, peak cardiac output ( Q̇peak ), and sweat rate were measured. PPO increased (p = 0.0003) and TT times decreased (p < 0.0001) from PRE to MID and POST in EXP but not CON. V̇O2max , T(re), T¯ (sk), heart rate, and Q̇peak remained stable in both groups. Sweat rate only increased in EXP from PRE to POST (p = 0.0197). Hb(mass) did not change in EXP. HA(M) potentiated hot exercise performance compared to HA, as demonstrated by improvements in both temperate and hot conditions. While HA(M) suffices to further develop thermal resistance, it is unsuitable to increase Hb(mass) following 10 days of HA or 3 weeks of HA(M). Our findings demonstrate that females can achieve HA by overdressing at home for 10 days and that HA(M) provides further benefits.