Cold-Water Immersion and the Treatment of Hyperthermia: Using 38.6°C as a Safe Rectal Temperature Cooling Limit
Bibliographic record
Abstract
CONTEXT: Cold-water immersion is recommended for the immediate field treatment of exertional heat stroke. However, concerns exist over potential overcooling of hyperthermic individuals during cold-water immersion. OBJECTIVE: To evaluate the recommendation that removing previously hyperthermic individuals from a cold-water bath at a rectal temperature (T(re)) of 38.6°C would attenuate overcooling. DESIGN: Controlled laboratory study. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Participants included 6 men and 4 women (age = 22 ± 3 years, height = 172 ± 10 cm, mass = 67.8 ± 10.7 kg, body fat percentage = 17.1% ± 4.5%, maximum oxygen consumption = 59.3 ± 8.7 mL·kg(-1)·min(-1)). INTERVENTION(S): After exercising at an ambient temperature of 40.0°C for 38.5 ± 9.4 minutes, until T(re) reached 39.5°C, participants were immersed in a 2.0°C circulated water bath until T(re) decreased to either 37.5°C or 38.6°C. Subsequently, participants were removed from the water bath and recovered for 20 minutes at an ambient temperature of 25°C. MAIN OUTCOME MEASURE(S): Rectal and esophageal temperatures were measured continuously during the immersion and recovery periods. RESULTS: Because of the experimental design, the overall time of immersion was greater during the 37.5°C trial (16.6 ± 5.7 minutes) than the 38.6°C trial (8.8 ± 2.6 minutes) (t(9) = -4.740, P = .001). During the recovery period after cold-water immersion, both rectal (F(1,9) = 50.540, P < .001) and esophageal (F(1,6) = 20.365, P = .007) temperatures remained greater in the 38.6°C trial than in the 37.5°C trial. This was evidenced by low points of 36.47°C ± 0.70°C and 37.19°C ± 0.71°C for rectal temperature (t(9) = 2.975, P = .016) and of 35.67°C ± 1.27°C and 36.72°C ± 0.95°C for esophageal temperature (t(6) = 3.963, P = .007) during the recovery period of the 37.5°C and 38.6°C trials, respectively. CONCLUSIONS: Immersion for approximately 9 minutes to a rectal temperature cooling limit of 38.6°C negated any risk associated with overcooling hyperthermic individuals when they were immersed in 2°C water.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".