HEAT EXHAUSTION IN THE SUN-HERALD CITY TO SURF FUN RUN

Objective: To investigate the relationship between motivational factors and physical and biological causes of heat exhaustion in fun run entrants. Design and setting: Case-control study, The Sun-Herald City to Surf fun runs in Sydney in 1991 and 1992. Participants: There were 63732 race entrants who completed the run and received a finishing time; 79 runners with heat exhaustion and 310 age, sex and performance matched controls were enrolled in the study. Main outcome measure: A diagnosis of heat exhaustion was made if a runner collapsed and, when first receiving medical care, had a rectal temperature of 38 degrees C or higher. Results: Two readily identifiable groups of runners were at high risk of heat exhaustion - accomplished non-elite (preferred) runners and runners of good ability (Group A). The attack rate was highest among accomplished non-elite runners, but a combination of a relatively high rate and the large number of entrants in Group A runners accounted for most cases. Four major risk factors for heat exhaustion were identified: motivation to exceed previous performance targets; failure to drink fluids during the run; failure of trained runners to acclimatise for the race by training in the warmer parts of the day; and previous history of heat exhaustion. Conclusion: Information from this investigation will enable more effective targeting of educational prevention programs in The Sun-Herald City to Surf fun run and provide baseline data for monitoring the effectiveness of these programs to modify high risk behaviour by participants.