Reproducibility of body temperature response to standardized test conditions when assessing clothing

Abstract

The traditional use of core temperature to assess the thermal effects of clothing has recently been questioned. The purpose of this study was to assess the reproducibility of body temperature in five subjects (mean age, 22.6 +/- 1.5 years) wearing either athletic clothing or a chemical protective overgarment while exercising at 20 degrees C and at 40 degrees C. The exercise was preceded by a 1 h adaptation period in a controlled environmental chamber. Results indicated that mean group change in rectal temperature (delta Tr) appeared to be reproducible for both garment ensembles at 20 degrees C but not at 40 degrees C. For mean change in oesophageal temperature (delta T(oes)) at 20 degrees C, reproducibility was obtained for the overgarment but not for the athletic garment; at 40 degrees C, mean delta T(oes) appeared to be reproducible with both garments. However, when individual responses were examined, there was little reproducibility for either delta Tr or delta T(oes). In addition, these measurements failed to show differences in the types of clothing worn. It was concluded that the use of core temperature to assess heat stress imposed by wearing clothing during exercise may lead to erroneous conclusions.

Changes in exercise and post-exercise core temperature under different clothing conditions

“…This work intensity was similar to that used by Thoden et al (1994) and Jetté et al (1995), and was found to be about the maximum that could be maintained by all subjects, under all conditions of clothing, for an 18-min period.…”

“…Previous studies have reported significant differences in T re between different levels of insulation (Nunneley 1989;Kraning and Gonzalez 1991). Jetté et al (1995) employed a similar exercise duration except that the exercise was performed at a lower intensity (45% VO 2max ) than that used for our study (75% VO 2max ). They were unable to demonstrate significant differences between clothing conditions (i.e., athletic clothing versus NBCW overgarment) at low T am (i.e., 20°C) in both T re and T es responses.…”

“…Jetté et al (1995) extended this conclusion to include the use of esophageal temperature (T es ) over a wide range of ambient temperature (T am ) conditions (20-40°C). However, their study required subjects to perform eight experimental trials separated by a minimum of 48 h between trials.…”

The Validity and Reliability of Intestinal Temperature during Intermittent Running

“…The T core response when repeating a fixed-intensity exercise test may vary on separate occasions regardless of whether basal T core is standardized before exercise (10). Jette and colleagues (10) examined the reproducibility of moderate increases in T core during treadmill exercise in varying environmental temperatures. They report that whereas the change in T rec was reproducible when exercising at 20-C (increase in T rec of approximately 0.3-C), it was dissimilar when comparing trials at 40-C (increase in T rec of approximately 0.5-C; significant difference of 0.04-C between trials).…”

Fluid balance, thermal stress, and post exercise response in women’s Islamic athletic clothing

“…During the 40-min recovery period, no apparent difference was observed at any time between the clothing types. It should be noted as addressed by Jetté et al (1995) that even in the case of greatly different clothing the influence of clothing may be masked due to high intra-individual variation. They concluded that erroneous conclusions maybe reached when examining heat stress by means of core temperature with various clothing during exercise.…”