Validity and Reliability of Devices That Assess Body Temperature During Indoor Exercise in the Heat

Abstract

Context: When assessing exercise hyperthermia outdoors, the validity of certain commonly used body temperature measuring devices has been questioned. A controlled laboratory environment is generally less influenced by environmental factors (eg, ambient temperature, solar radiation, wind) than an outdoor setting. The validity of these temperature measuring devices in a controlled environment may be more acceptable.Objective: To assess the validity and reliability of commonly used temperature devices compared with rectal temperature in individuals exercising in a controlled, high environmental temperature indoor setting and then resting in a cool environment.Design: Time series study. Setting: Laboratory environmental chamber (temperature 5 36.4 6 1.26C [97.5 6 2.166F], relative humidity 5 52%) and cool laboratory (temperature 5 approximately 23.36C [74.06F], relative humidity 5 40%).Patients or Other Participants: Fifteen males and 10 females.Intervention(s): Rectal, gastrointestinal, forehead, oral, aural, temporal, and axillary temperatures were measured with commonly used temperature devices. Temperature was measured before and 20 minutes after entering the environmental chamber, every 30 minutes during a 90-minute treadmill walk in the heat, and every 20 minutes during a 60-minute rest in mild conditions. Device validity and reliability were assessed with various statistical measures to compare the measurements using each device with rectal temperature. A device was considered invalid if the mean bias (average difference between rectal and device temperatures) was more than 60.276C (60.506F).Main Outcome Measure(s): Measured temperature from each device (mean and across time).Results: Conclusions: Even during laboratory exercise in a controlled environment, devices used to measure forehead, temporal, oral, aural, and axillary body sites did not provide valid estimates of rectal temperature. Only intestinal temperature measurement met the criterion. Therefore, we recommend that rectal or intestinal temperature be used to assess hyperthermia in individuals exercising indoors in the heat.Key Words: core body temperature, hyperthermia, tympanic membrane Key Points N As indicated by mean bias values, invalid estimates of rectal temperature (the ''gold standard'') were provided by forehead sticker, oral temperature, temporal temperature, aural temperature, and axillary temperature.N Intestinal temperature was the only measurement considered valid. N Successive intestinal, forehead sticker, temporal, and aural measurements demonstrated acceptable reliability.

Evidence-Based Practice and the Recognition and Treatment of Exertional Heat Stroke, Part I: A Perspective From the Athletic Training Educator

“…35,36 The use of an ingestible thermistor or an esophageal thermometer is expensive and impractical for field application when compared with obtaining a rectal temperature. 37 We believe that, despite their misgivings, misconceptions, and lack of comfort, ATs and AT educators must embrace T re and CWI to prevent unnecessary deaths.…”

Exertional Heat Stroke in Navy and Marine Personnel: A Hot Topic

“…41 Lactated Ringer solution is not used, because liver function can be suppressed by overheated tissues, leading to unmetabolized lactate and worsening lactic acidosis. 20 Numerous studies [42][43][44] have demonstrated that axillary, aural (tympanic), oral, and skin temperatures often indicate a falsely low T core , especially after intense exercise in the heat. Rectal temperature remains the reference standard for assessment Central nervous system abnormalities such as confusion and agitation often are the first signs of heat stroke.…”

Reliability of Intestinal Temperature Using an Ingestible Telemetry Pill System During Exercise in a Hot Environment

“…Esophageal and rectal sites are most commonly used for assessing core body temperature (6,30); however, ingestible telemetry pill systems that measure intestinal temperature are being increasingly used to overcome the impracticalities associated with traditional methods (5). Several studies provide evidence to suggest that telemetry pill systems are valid tools for assessment of core temperature (13,15,16,25,26); however, there are little data regarding the reliability of intestinal temperature measurement during exercise in a hot environment.…”