Optimal cooling strategies for players in Australian Tennis Open conditions

Abstract

Objectives: We compared the utility of four cooling interventions for reducing heat strain during simulated tennis match-play in an environment representative of the peak conditions possible at the Australian Open (45°C, <10% RH, 475W/m² solar radiation).

Design: Nine trained males undertook four trials in a climate chamber, each time completing 4 sets of simulated match-play.

Methods: During ITF-mandated breaks (90-s between odd-numbered games; 120-s between sets), either iced towels (ICE), an electric fan (FAN_dry), a fan with moisture applied to the skin (FAN_wet), or ad libitum 10°C water ingestion only (CON) was administered. Rectal temperature (T_re), mean skin temperature (T_sk), heart rate (HR), thermal sensation (TS), perceived exertion (RPE) and whole body sweating (WBSR) were measured.

Results: After set 3, T_re was lower in ICE (38.2±0.3°C) compared to FAN_dry (38.7±0.5°C; p=0.02) and CON (38.5±0.5°C; p=0.05), while T_re in FAN_wet (38.2±0.3°C) was lower than FAN_dry (p=0.05). End-exercise T_re was lower in ICE (38.1±0.3°C) and FAN_wet (38.2±0.4°C) than FAN_dry (38.9±0.7°C; p<0.04) and CON (38.8±0.5°C; p<0.04).T_sk for ICE (35.3±0.8°C) was lower than all conditions, and T_sk for FAN_wet (36.6±1.1°C) was lower than FAN_dry (38.1±1.3°C; p<0.05). TS for ICE and FAN_wet were lower than CON and FAN_dry (p<0.05). HR was suppressed in ICE and FAN_wet relative to CON and FAN_dry (p<0.05). WBSR was greater in FAN_dry compared to FAN_wet (p<0.01) and ICE (p<0.001).

Conclusions: Fan use must be used with skin wetting to be effective in hot/dry conditions. This strategy and the currently recommended ICE intervention both reduced T_re by ∼0.5-0.6°C and T_sk by ∼1.0-1.5°C while mitigating rises in HR and TS.

Keywords: Core temperature; Heat balance; Heat exchange; Sweating.