A recent study published in the British Journal of Sports Medicine shows that, in spite of the hot and humid conditions frequently encountered on the FIVB Beach Volleyball World Tour, there were no cases of heat-related match forfeits during three seasons (2007-2011).
During a professional FIVB Beach Volleyball World Tour Grand Slam event in 2007, one team forfeited the final when a player could not continue competing due to the effects of heat stress.
The athlete recovered fully, but the FIVB – the international volleyball federation – established its Heat Stress Monitoring Program to safeguard the health of the athletes.
The challenge facing tournament officials and organizers is to determine when is hot too hot to play?
During this 2007 event, the maximum recorded air temperature was 34°C and the maximum recorded wet-bulb globe temperature (WBGT) was 32°C.
The WBGT is a composite value used to estimate the combined effect of temperature, humidity, wind speed (wind chill) and solar radiation on humans. The WBGT is generally considered to be the best measure of heat stress.
Warning flag concept to indicate level of risk
Several systems utilising the WBGT have been developed in order to estimate the risk of developing heat illness under varying environmental conditions. Historically, organizations like the American College of Sports Medicine (ACSM) and the United States Navy have adopted the ‘warning flag’ concept to indicate the level of risk from exposure to high heat and humidity.
The current ACSM guideline states that uncompensable heat stress exists for all types of activity for all athletes when the WBGT reading exceeds 32.3°C. This is equivalent to the US Navy black flag condition, considered to be the upper limit for physical activity in hot and humid conditions.
However, anecdotal evidence provided by players, FIVB officials and FIVB Medical Commission members suggested that there had been only very few cases of medical forfeits due to heat exhaustion on the World Tour despite frequent exposure to conditions well above ‘black flag’ conditions, probably reflecting the fact that virtually all athletes on tour are well acclimatised to the heat, and that the players were experienced and well educated on safe hydration practices.
FIVB Heat Stress Monitoring Program
The results from the FIVB Heat Stress Monitoring Program show that of 48 tournaments on the World Tour, there were 9 events where the peak WBGT met the US Navy black flag condition of >32.3°C and an additional two events where the peak WBGT exceeded 31°C (US Navy red flag conditions). However, despite this there were no match forfeits which could be attributed to these environmental conditions alone.
Thus, the study concluded that the incidence of significant heat illness in professional beach volleyball on the World Tour is low, even though hot and humid conditions are encountered frequently. Also, the data show that the currently available heat stress guidelines are inadequate to fully appreciate the sport-specific risk of heat illness, and thus to help inform reasonable safety decisions.
This study was conducted by Professor Roald Bahr, Head of the Medical Commission of the FIVB, and Jonathan Reeser.
Read the paper in British Journal of Sport Medicine