title: High work output combined with high ambient temperatures caused heat exhaustion in a wildland firefighter despite high fluid intake.
abstract: The purpose of this case study is to examine the physiological/behavioral factors leading up to heat exhaustion in a male wildland firefighter during wildland fire suppression. The participant (24 years old, 173 cm, 70 kg, and 3 years firefighting experience) experienced heat exhaustion following 7 hours of high ambient temperatures and arduous work on the fire line during the month of August. At the time of the heat-related incident (HRI), core temperature was 40.1 °C (104.2 °F) and skin temperature was 34.4 °C (93.9 °F). His work output averaged 1067 counts·min(-1) (arbitrary units for measuring activity) for the 7 hours prior to the HRI, a very high rate of work over an extended time period during wildfire suppression. In the 2.5 hours leading up to the heat incident, he was exposed to a mean ambient temperature of 44.6 °C (112.3 °F), with a maximum temperature of 59.7 °C (139.5 °F). He consumed an average of 840 mL·h(-1) in the 7 hours leading up to the incident and took an average of 24 ± 11 drinks·h(-1) (total of 170 drinks). The combined effects of a high work rate and high ambient temperatures resulted in an elevated core temperature and a higher volume and frequency of drinking than typically seen in this population, ultimately ending in heat exhaustion and removal from the fire line. The data demonstrate that heat-related incidents can occur even with aggressive fluid intake during wildland fire suppression.
authors.affiliation: Montana Center for Work Physiology and Exercise Metabolism, The University of Montana, Missoula, MT 59812-1825, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Cuddy
authors.forename: Brent C
authors.initials: BC
authors.lastname: Ruby
mesh_terms: D001831:Body Temperature; D004326:Drinking; D005390:Fires; D006359:Heat Exhaustion / Q000209:etiology / Q000503:physiopathology*; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D005082:Physical Exertion; D055815:Young Adult