Comparison of estimated core body temperature measured with the BioHarness and rectal temperature under several heat stress conditions

Abstract

Monitoring and measuring core body temperature is important to prevent or minimize physiological strain and cognitive dysfunction for workers such as first responders (e.g., firefighters) and military personnel. The purpose of this study is to compare estimated core body temperature (Tco-est), determined by heart rate (HR) data from a wearable chest strap physiology monitor, to standard rectal thermometry (Tre) under different conditions. Tco-est and Tre measurements were obtained in thermoneutral and heat stress conditions (high temperature and relative humidity) during four different experiments including treadmill exercise, cycling exercise, passive heat stress, and treadmill exercise while wearing personal protective equipment (PPE). Overall, the mean Tco-est did not differ significantly from Tre across the four conditions. During exercise at low-moderate work rates under heat stress conditions, Tco-est was consistently higher than Tre at all-time points. Tco-est underestimated temperature compared to Tre at rest in heat stress conditions and at a low work rate under heat stress while wearing PPE. The mean differences between the two measurements ranged from -0.1 ± 0.4 to 0.3 ± 0.4°C and Tco-est correlated well with HR (r = 0.795 - 0.849) and mean body temperature (r = 0.637 - 0.861). These results indicate that, the comparison of Tco-est to Tre may result in over- or underestimation which could possibly lead to heat-related illness during monitoring in certain conditions. Modifications to the current algorithm should be considered to address such issues.

Wearable physiological monitoring for human thermal-work strain optimization

“…One would expect from passive heating that the algorithm would underestimate the rise in T c , since there is no heat-generating information contained in the heart rate. The unexpected underestimation for passive heating was reported by Seo et al (75) in their validation of the algorithm implemented in a commercial PSM device. Seo et al also found that the algorithm had acceptable performance for both treadmill and cycle exercise.…”

Validity of a noninvasive estimation of deep body temperature when wearing personal protective equipment during exercise and recovery

“…Further studies among military populations have confirmed similar levels of agreement [RMSD 0.21 °C; systematic bias (0.02 ± 0.11) °C; 95% LoA ±0.48 °C] when conducting work wearing chemical and biological (CB) protective clothing [27], when wearing combat uniforms during jungle operations (− 0.01 °C; 95% LoA ±0.58 °C) [28], and during road marching (0.02 °C; 95% LoA ±0.76 °C) [23]. Slightly wider systematic bias has been observed during treadmill exercise wearing athletic clothing [(0.3 ± 0.4) °C; 95% LoA ± 0.7 °C) or CB protective clothing [(− 0.1 ± 0.4) °C; 95% LoA ±0.7 °C] [29]. These studies have shown that ECTemp, while not a replacement for direct measurement techniques, provides a noninvasive indication of deep body temperature that could easily be implemented in a range of athletic and occupational situations, such as technicians wearing EOD protective clothing.…”

Pay, Power, and Health: HRI and the Agricultural Conundrum

“…And yet, high numbers of deaths occur among agricultural workers annually that are attributed to HRI. From current research on core body temperature and the effects of hydration, clothing, work-rate and environmental conditions (Courville, Wadsworth, and Schenker 2016;Hoyt et al 2017;Schenker 2013;Seo et al 2016), it is clear that simply training workers to drink more water or rest in the shade will not necessarily decrease occurrence of HRI. Between the years 1992 and 2013, at least 689 workers in the United States died from HRI, and 56,114 were injured severely enough to result in days away from work (Centers for Disease Control and Prevention 2008;U.S.…”