Differences in salivary hormones and perception of exertion in elite women and men volleyball players during tournament.

BACKGROUND: Sports tournaments induce both psychological and physiological stress, which seems to be different between men and women. Competition induces anticipatory rises in testosterone and cortisol levels, which may affect performance and physical exertion during tournaments. The aim of this study was to compare the changes in salivary cortisol and testosterone concentrations between men and women during an official volleyball tournament and to test potential correlations between changes in these hormones and perceived exertion after match. METHODS: Three matches of each team were assessed in the group stage of the Men and Women South American Volleyball Championship. Salivary cortisol and testosterone levels were measured in the fasting state, before and after each match. The rate of perceived exertion (RPE) was assessed after each match. RESULTS: Fasting cortisol concentrations were higher in women than men (~25%, P<0.001) while fasting testosterone was higher in men than women (~46%, P<0.001). Cortisol concentration increased only after the second match in men (+53.7%, P<0.001). Testosterone concentration was low before and after the third match in men (P<0.001) while it was elevated after the third match in women (P=0.003). The rate of perceived exertion was correlated with the change in testosterone levels due to the matches in both women (r=0.33; P=0.04) and men (r=0.44; P=0.02), which was not observed for cortisol concentrations. CONCLUSIONS: These results indicate that women have higher fasting cortisol, but lower fasting testosterone concentrations than men during a volleyball tournament. Thus, hormonal responses of women and men are different and related to their effort during the matches.

Influence of a Gas Exchange Correction Procedure on Resting Metabolic Rate and Respiratory Quotient in Humans.

OBJECTIVE: The aim of this study was to determine the influence of a gas exchange correction protocol on resting metabolic rate (RMR) and respiratory quotient (RQ), assessed by a Vmax Encore 29n metabolic cart (SensorMedics Co., Yorba Linda, California) in overnight fasted and fed humans, and to assess the predictive power of body size for corrected and uncorrected RMR. METHODS: Healthy participants (23 M/29 F; 34 ± 9 years old; 26.3 ± 3.7 kg/m2 ) ingested two 3-hour-apart glucose loads (75 g). Indirect calorimetry was conducted before and hourly over a 6-hour period. Immediately after indirect calorimetry assessment, gas exchange was simulated through high-precision mass-flow regulators, which permitted the correction of RMR and RQ values. RESULTS: Uncorrected and corrected RMR and RQ were directly related at each time over the 6-hour period. However, uncorrected versus corrected RMR was 6.9% ± 0.5% higher (128 ± 7 kcal/d; P < 0.0001), while RQ was 14.0 ± 0.4% lower (-0.114 ± 0.003; P < 0.0001) when compared throughout the whole period. Body weight, sex, and age explained a larger fraction of the variance when corrected RMR was considered (adjusted R2 = 0.71; P < 0.0001) versus uncorrected RMR (adjusted R2 = 0.59; P < 0.0001). CONCLUSIONS: Applying a protocol to correct gas exchange in humans over a 6-hour period is feasible and provides information of improved accuracy.