Published: J Athl Train, accepted 2010
Conditions in professional women's tennis tournaments could expose players to significant heat stress and dehydration, but to date little information on temperature response and hydration has been gathered during tournament play.
PURPOSE: To determine sodium losses in sweat, fluid balance, and change in core temperature (Tc) in professional female tennis players during tournament matches in the heat.
METHODS: Measurements were taken during a sanctioned Tier III tournament in the heat (WBGT = 29.9 ± 3.1°C) on 13 female professional tennis players (age 22.7 ± 3.6 y, weight 66.0 ± 7.2 kg, height 1.7 ± 0.04 m). During a practice session preceding tournament play, a forearm sweat sample was collected using a regional sweat patch technique to determine sweat sodium concentration. Fluid intake, sweat losses (determined by body mass changes), and Tc (Ingestible temperature pill, HQ Inc.) were also recorded during match play in 10 of the 13 athletes. A repeated measures ANOVA (Duncan Post Hoc) was used to determine significance in Tc change (α=0.05).
RESULTS: Mean (± SD) sweat sodium concentration during practice was 39.1 ± 10.7 mmol/L. According to pre-match urine specific gravity measurements (USG), it appears most players began their match in a dehydrated state (USG 1.024 ± 0.004). Mean match time was 107.7 ± 40.1 min; fluid intake during the match was 2.6 ±1.0 L, and change in body weight was -0.6 ± 0.7 kg, resulting in a calculated sweat rate of 1.8±0.5L/h(1.0±0.2L/m2/h). Tc during the match was 38.7 ± 0.2°C, with a peak Tc of 39.1 ±0.3°C. Pre-to post-match Tc increased 1.1 ± 0.4°C (n=10, P<0.05). Seven of the 10 players monitored for Tc response took a 10-min break (WTA Extreme Weather Condition (EWC) rule or bathroom) during the match. Tc changed from 38.92°C to 38.67°C (dTc -0.25 ± 0.20°C; P>0.05) when a break was taken.
CONCLUSION: Peak Tc data showed that female professional tennis players can be subjected to high heat loads during match play in hot environments. The sweat rates in this group of professional tennis players were high compared to other female athletes, however the sweat sodium concentrations fell within normal ranges. While not statistically significant, Tc decreased in 6 out of 7 players after a 10-min break. The break provides practical significance when applied in the field, though more research is recommended.
Tippet ML, Stofan JR, Lacambra M, and Horswill CA. Core temperature and sweat responses in professional women’s tennis during tournament play in the heat. J Athl Train, accepted 2010.