Objective: To investigate the relationship between motivational factor
s and physical and biological causes of heat exhaustion in fun run ent
rants. Design and setting: Case-control study, The Sun-Herald City to
Surf fun runs in Sydney in 1991 and 1992. Participants: There were 637
32 race entrants who completed the run and received a finishing time;
79 runners with heat exhaustion and 310 age, sex and performance match
ed controls were enrolled in the study. Main outcome measure: A diagno
sis of heat exhaustion was made if a runner collapsed and, when first
receiving medical care, had a rectal temperature of 38 degrees C or hi
gher. 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 amo
ng accomplished non-elite runners, but a combination of a relatively h
igh rate and the large number of entrants in Group A runners accounted
for most cases. Four major risk factors for heat exhaustion were iden
tified: 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 investi
gation will enable more effective targeting of educational prevention
programs in The Sun-Herald City to Surf fun run and provide baseline d
ata for monitoring the effectiveness of these programs to modify high
risk behaviour by participants.