Effectiveness of cold water immersion for treating exertional heat stress when immediate response is not possible

Abstract

Immediate treatment with cold water immersion (CWI)is the gold standard for exertional heatstroke. In the field, however, treatment is often delayed due to delayed paramedic response and/or inaccurate diagnosis. We examined the effect of treatment (reduction of rectal temperature to 37.5°C) delays of 5, 20, and 40 min on core cooling rates in eight exertionally heat-stressed (40.0°C rectal temperature) individuals. We found that rectal temperature was elevated above baseline (P < 0. We conclude that the effectiveness of 2°C CWI as a treatment for exertional heat stress remains high even when applied with a delay of 40 min. Therefore, our results support that CWI is the most appropriate treatment for exertional heatstroke as it is capable of quickly reversing hyperthermia even when treatment is commenced with a significant delay.

Heart rate variability dynamics during treatment for exertional heat strain when immediate response is not possible

“…Therefore, our results suggest that CWI transiently improves the cardioprotective background even when applied with a delay of 40 min. Taken together with our previous finding that a 40 min delay in application of CWI to treat EHS does not affect the core cooling rate or the post‐immersion core temperature after‐drop (Flouris et al., ), our results are compatible with the conclusion that CWI is the most appropriate treatment for EHS.…”

“…Core temperature values (means ± SD) across the protocol stages during the three trials incorporating a short (5 min), moderate (20 min) or prolonged (40 min) postexercise recovery period to simulate treatment delay. Some of these data are part of Table in the paper presenting the main thermoregulatory findings from this work (Flouris et al., ). a Significant difference ( P ≤ 0.005) between the short and the moderate delay.…”

“…This can be the result of a failure to recognize the presence or seriousness of EHS and/or the absence of medical personnel to care TA B L E 1 Statistically significant (at the 0.005 level) main and interaction effects from the mixed-design ANOVA assessing the impact of treatment delay and protocol stage on core temperature, heart rate and indices of heart rate variability F I G U R E 1 Core temperature values (means ± SD) across the protocol stages during the three trials incorporating a short (5 min), moderate (20 min) or prolonged (40 min) postexercise recovery period to simulate treatment delay. Some of these data are part of Table 1 in the paper presenting the main thermoregulatory findings from this work (Flouris et al, 2015). a Significant difference (P ≤ 0.005) between the short and the moderate delay.…”

“…Oesophageal and rectal temperatures were measured throughout with general purpose thermocouple temperature probes (Mallinckrodt Medical Inc., St Louis, MO, USA) using previous methodology (Flouris et al., ) every 15 s using an HP Agilent data acquisition module (model 3497A) and simultaneously displayed and recorded in spreadsheet format with LabVIEW software (v.7.0; National Instruments Corporation, Austin, TX, USA). The average of oesophageal and rectal temperature was used as an index of core temperature.…”

“…Ample field and laboratory evidence has shown that immediate cold water (2–4°C) immersion (CWI) (Casa et al., ; Demartini et al., ; Flouris et al., ; Proulx et al., ) with the aim of reducing the core temperature of the patient to near‐normal resting levels is the best treatment for EHS (Casa et al., ; Casa, Armstrong, Kenny, O'Connor, & Huggins, ; Flouris et al., ; Flouris, Friesen, Carlson, Casa, & Kenny, ). Delay in the application of CWI treatment can lead to morbidity and mortality (Casa et al., ; Zeller, Novack, Barski, Jotkowitz, & Almog, ), because the length of time that core temperature remains above critical levels is linked to the severity and reversibility of multisystem organ failure in EHS (Casa et al., ; Hubbard et al., ; Zeller et al., ).…”