Effect of acute heat exposure on the determination of critical power and W & PRIME; in women and men

The goal of this study was to investigate to what extent acute heat exposure would affect the parameters of the power-duration relationship, i.e. CP and W & PRIME;, using multiple constant workload tests to task failure, in women and men. Twenty four young physically active participants (12 men, 12 women) performed 3-5 constant load tests to determine CP and W & PRIME;, both in temperate (TEMP; 18 & DEG;C) and hot (HOT; 36 & DEG;C) environmental conditions. A repeated-measures ANOVA was executed to find differences between TEMP and HOT, and between women and men. In HOT, CP was reduced by 6.5% (227 & PLUSMN; 50 vs. 212 & PLUSMN; 47 W), while W & PRIME; increased 12.4% (16.4 & PLUSMN; 4.4 vs. 18.5 & PLUSMN; 5.6 kJ). No significant two-way sex x temperature interactions were observed, indicating that the environmental conditions did not have a different effect in men compared with women. The intersection of the average curvatures in TEMP and HOT occurred at 137 s and 280 W in women, and 153 s and 397 W in men. Acute heat exposure had an impact on the parameters CP and W & PRIME;, i.e. CP decreased whereas W & PRIME; increased. The increase in W & PRIME; might be a consequence of the mathematical modelling for the used test methodology, rather than a physiological accurate value of W & PRIME; in HOT. No differences induced by heat exposure were observed between women and men.