Validity of devices that assess body temperature during outdoor exercise in the heat.
BACKGROUND
Rectal temperature is recommended by the National Athletic Trainers' Association as the criterion standard for recognizing exertional heat stroke, but other body sites commonly are used to measure temperature. Few authors have assessed the validity of the thermometers that measure body temperature at these sites in athletic settings.


OBJECTIVE
To assess the validity of commonly used temperature devices at various body sites during outdoor exercise in the heat.


METHODS
Observational field study.


METHODS
Outdoor athletic facilities.


METHODS
Fifteen men and 10 women (age = 26.5 +/- 5.3 years, height = 174.3 +/- 11.1 cm, mass = 72.73 +/- 15.95 kg, body fat = 16.2 +/- 5.5%).


METHODS
We simultaneously tested inexpensive and expensive devices orally and in the axillary region, along with measures of aural, gastrointestinal, forehead, temporal, and rectal temperatures. Temporal temperature was measured according to the instruction manual and a modified method observed in medical tents at local road races. We also measured forehead temperatures directly on the athletic field (other measures occurred in a covered pavilion) where solar radiation was greater. Rectal temperature was the criterion standard used to assess the validity of all other devices. Subjects' temperatures were measured before exercise, every 60 minutes during 180 minutes of exercise, and every 20 minutes for 60 minutes of postexercise recovery. Temperature devices were considered invalid if the mean bias (average difference between rectal temperature and device temperature) was greater than +/-0.27 degrees C (+/-0.5 degrees F).


METHODS
Temperature from each device at each site and time point.


RESULTS
Mean bias for the following temperatures was greater than the allowed limit of +/-0.27 degrees C (+/-0.5 degrees F): temperature obtained via expensive oral device (-1.20 degrees C [-2.17 degrees F]), inexpensive oral device (-1.67 degrees C [-3.00 degrees F]), expensive axillary device (-2.58 degrees C [-4.65 degrees F]), inexpensive axillary device (-2.07 degrees C [-3.73 degrees F]), aural method (-1.00 degrees C [-1.80 degrees F]), temporal method according to instruction manual (-1.46 degrees C [-2.64 degrees F]), modified temporal method (-1.36 degrees C [-2.44 degrees F]), and forehead temperature on the athletic field (0.60 degrees C [1.08 degrees F]). Mean bias for gastrointestinal temperature (-0.19 degrees C [-0.34 degrees F]) and forehead temperature in the pavillion (-0.14 degrees C [-0.25 degrees F]) was less than the allowed limit of +/-0.27 degrees C (+/-0.5 degrees F). Forehead temperature depended on the setting in which it was measured and showed greater variation than other temperatures.


CONCLUSIONS
Compared with rectal temperature (the criterion standard), gastrointestinal temperature was the only measurement that accurately assessed core body temperature. Oral, axillary, aural, temporal, and field forehead temperatures were significantly different from rectal temperature and, therefore, are considered invalid for assessing hyperthermia in individuals exercising outdoors in the heat.
Human Performance Laboratory, Department of Kinesiology, Neag Schoolof Education, University of Connecticut, 2095 Hillside Road, U-1110, Storrs, CT 06269-1110, USA. douglas.casa@uconn.edu
Douglas J
DJ
Casa
Shannon M
SM
Becker
Matthew S
MS
Ganio
Christopher M
CM
Brown
Susan W
SW
Yeargin
Melissa W
MW
Roti
Jason
J
Siegler
Julie A
JA
Blowers
Neal R
NR
Glaviano
Robert A
RA
Huggins
Lawrence E
LE
Armstrong
Carl M
CM
Maresh
D000328:Adult; D001365:Axilla; D001831:Body Temperature; D002138:Calibration; D004423:Ear; D015444:Exercise / Q000502:physiology*; D005260:Female; D005546:Forehead; D041981:Gastrointestinal Tract; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009055:Mouth; D015203:Reproducibility of Results; D013177:Sports / Q000502:physiology; D013178:Sports Medicine / Q000295:instrumentation; D013821:Thermometers