Search

1. 1.Esophageal temperature [Tes (18.0 ± 6.1 min)] and pill temperature [Thti (25.3 ± 9.1 min)] reached steady state faster (P V O 2 ) than rectal temperature [Tre (37.3 ± 4.6 min)] at Ta = 29°C, Tdp = 11°C. Steady-state exercise temperatures were lower for Tes = 37.18 ± 0.18°C andThti = 37.20 ± 0.32°C than Tre = 37.46 ± 0.15°C (P 2. 2.During moderate exercise the change in core temperature per time (slope) was greater (P 3. 3.Overall, Thti tracked dynamic changes in core temperature significantly faster than Tre, although Thti did not track dynamic changes as well or as consistently as Tes. The concept of using a temperature sensor in a pill may be useful clinically, but mobility of the pill makes this temperature measurement less suitable for research than esophageal or rectal temperature measurements.

Thermoregulatory strain occurs in soldiers during field and laboratory tests of military equipment and systems. In laboratory tests, either rectal or esophageal temperature of the volunteers is monitored to ensure that internal body temperature (core temperature) does not exceed safe clinical limits. Each of these core temperature indices is reproducible and not biased by environmental temperature; however, the slow response time of rectal temperature is well known. Esophageal temperature measurements are not used in the field, but are routinely used in laboratory tests which are concerned with the study of thermoregulation. Rectal temperature measurements are used as a index of core temperature in the field and in some types of laboratory studies of exercise and heat stress responses. In the field, it is not always practical to monitor core temperature because volunteers reject the use of rectal probes as a clinical thermometer or the current portable system requires that a medical observer be close to the volunteer at all times. This methodology interferes with field exercises and requires large numbers of medical observers. For example, a medical observer would effectively disrupt the military mission of a tank crew while he monitors the core temperature of each crew member. A solution to monitoring core temperature during field exercises would be to monitor core temperature at an accepted internal site and to transmit the core temperature responses some distance from the test using telemetry. In this way, the medical observer could communicate to the crew or individual when core temperature limits have been exceeded. Alternatively, the individual could carry a temperature telemetry data logger that contained an alarm which would be activated if a core temperature safety limit were exceeded during the field exercise.