Assessment of core temperature measurement sites at rest and during exercise in a neutral, cold, and hot simulated microgravity environment

The purpose of this investigation was to examine the effect of simulated microgravity on the estimation of core temperature using aural, oral, and rectal temperatures, with esophageal temperature used as the criterion core temperature. of healthy males at rest and during programmed exercise in a neutral, a cold, and a hot ambient environment. Subjects were randomly ordered to six testing ambient environmental conditions: neutral environment at one gravity; neutral environment at simulated microgravity; cold environment at one gravity; cold environment at simulated microgravity; hot environment at one gravity; and, hot environment at simulated microgravity. Data were analyzed using a 2 ;A three-way interaction was observed for exertion, gravity, and temperature site in the neutral environment. Post-hoc analyses revealed that oral temperature was lower than the other sites for both one gravity and simulated microgravity. Orthogonal comparisons indicated that oral temperature was lower than esophageal temperature during exercise by ;A two-way interaction was observed for exertion and gravity in the cold environment. A main effect for temperature site was also observed with both aural and oral temperatures being lower than esophageal temperature.;A significant main effect for gravity was observed in the hot environment with the core temperature greater in one gravity than simulated microgravity. A two-way interaction for exercise and temperature site was observed. Post-hoc analyses revealed that aural and oral temperatures were lower during rest (;It was concluded that: (a) oral temperature was consistently lower than esophageal temperature in all environments; (b) esophageal, aural, and rectal temperatures may be used at rest and during exercise in a neutral environment; (c) gravity influenced the estimation of core temperatures in a cold environment; and, (d) the aural and rectal sites can be used during rest and the rectal site can be used during exercise to estimate core temperature regardless of gravity in an ambient hot environment.