Abstract
Reliability is an essential criteria if a test is to be considered valid. However, the reliability of critical environmental limits, have not been established. These limits are defined as where an ambient thermal burden is progressively incremented causing a point where deep body temperature increases without returning to stability, indicating that the conditions for thermal balance are no longer satisfied because of excessive dry heat gain or insufficient evaporative heat loss. Two studies were conducted to: i) determine the reliability of the deep body temperature (Tre) inflection point under conditions of low- and high-humidity (LH and HH); ii) to establish whether the Tre inflection point determined with an continuous type protocol provides a valid index of the transition from a compensable (CO) to uncompensable (UN) thermal environment.
Study 1 method: n=8 healthy males completed two tests commencing at 34 °C, 20 % RH (LH) and two commencing at 28 °C, 80 % RH (HH) at 60 W. There were two phases in each trial: a) CO phase - 60 minutes at 60 W; b) UN phase – immediately following the CO phase, ambient temperature (Tdb) was increased by 1 °C every 5 minutes, UN was confirmed by an inflection in Tre (Treinfl). Study 2 method: n=9 healthy males completed two visits at 34 °C, 20 % RH at 60 W. Visit 1) protocol: as above in Study 1 and Visit 2) protocol: Tdb was raised as per Study 1, but then held at a Tdb just beyond the Treinfl point in Visit 1).
Study 1 showed that Treinfl was identified successfully using the Dmax method (used by previous authors) with low CV (<10%), had good face validity, and was less subjective than a purely visual approach. Study 2 showed that when Tdb was clamped in Visit 2, Tre continued to increase for a further 40 -60 minutes.
Thus, it appears that the protocol is reliable in causing a Treinfl (Study 1) and that participants had achieved an uncompensable thermal state when the Treinfl occurred (Study 2). Therefore, previous authors were correct to conclude that their protocols provide insight into thermal and non-thermal factors which affect the point of uncompensability in adults and children.
Study 1 method: n=8 healthy males completed two tests commencing at 34 °C, 20 % RH (LH) and two commencing at 28 °C, 80 % RH (HH) at 60 W. There were two phases in each trial: a) CO phase - 60 minutes at 60 W; b) UN phase – immediately following the CO phase, ambient temperature (Tdb) was increased by 1 °C every 5 minutes, UN was confirmed by an inflection in Tre (Treinfl). Study 2 method: n=9 healthy males completed two visits at 34 °C, 20 % RH at 60 W. Visit 1) protocol: as above in Study 1 and Visit 2) protocol: Tdb was raised as per Study 1, but then held at a Tdb just beyond the Treinfl point in Visit 1).
Study 1 showed that Treinfl was identified successfully using the Dmax method (used by previous authors) with low CV (<10%), had good face validity, and was less subjective than a purely visual approach. Study 2 showed that when Tdb was clamped in Visit 2, Tre continued to increase for a further 40 -60 minutes.
Thus, it appears that the protocol is reliable in causing a Treinfl (Study 1) and that participants had achieved an uncompensable thermal state when the Treinfl occurred (Study 2). Therefore, previous authors were correct to conclude that their protocols provide insight into thermal and non-thermal factors which affect the point of uncompensability in adults and children.
Original language | English |
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Pages | 196 |
Number of pages | 1 |
Publication status | Published - 1 Nov 2017 |
Event | The 17th International Conference on Environmental Ergonomics (ICEE 2017, Kobe) - Kobe, Japan Duration: 12 Nov 2017 → 17 Nov 2017 |
Conference
Conference | The 17th International Conference on Environmental Ergonomics (ICEE 2017, Kobe) |
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Country/Territory | Japan |
City | Kobe |
Period | 12/11/17 → 17/11/17 |