Influence of ambient and core temperatures on auditory canal temperature.
Ear canal temperature (Tac) is a useful indicator of human body temperature under some laboratory conditions. Tac has also been used in field studies, but problems arise there due to its susceptibility to external influences such as wind. Experiments on five resting subjects in an environmental chamber showed that 1) compared to a warm environment (35 degrees C), a cool one (22 degrees C) produced significant lowering of both Tac and rectal temperature (Tre), 2) the cool condition increased the difference between Tre and Tac, and 3) head treatment (helmet wear, wind) significantly affected Tac. In a second series of experiments, six subjects exposed to the same conditions performed mild exercise to abolish the progressive decline in Tre seen at 22 degrees C. Results showed that Tac still reflected external temperature and continued to show the influence of head treatment.


CONCLUSIONS
Tac has only limited usefulness in aircrew studies or other field work unless subjects can wear a protective helmet throughout the period of data collection.
D000328:Adult; D001831:Body Temperature; D004424:Ear Canal / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D013696:Temperature; D014919:Wind