Influence Of Slow Versus Fast Ramp Exercise-induced Hyperthermia On Core Cooling Rates During Ice-water Immersion
Bibliographic record
Abstract
Identifying potential factors which may alter the efficacy of cooling treatments is critical for the treatment of exertional heat stroke victims. Current evidence strongly supports the use of cold water immersion as the most potent method for rapidly reducing body core temperature. However, it is unclear if differences in the level of cardiovascular strain following exercise-induced hyperthermia may influence this response. PURPOSE: To compare core cooling rates during 2°C ice-water immersion of subjects rendered hyperthermic by either a low (Slow heating, SH) or moderate (Fast heating, FH) exercise intensity performed in the heat. METHODS: On 2 separate days, seven subjects (5 males, 2 females) either walked (4 mph, 2% grade, SH) or ran (7.5 mph, 2% grade, FH) on a treadmill until rectal temperature (Tre) increased to 39.5°C. After exercise, the subjects were immersed to the clavicles in a circulated water bath controlled at 2°C until Tre returned to 38.0°C. Heart rate, mean arterial pressure (MAP) and blood plasma volume were assessed during baseline rest and prior to ice-water immersion. RESULTS: End-exercise Tre was similar between SH (39.51±0.01°C) and FH (39.51±0.01°C). However, the time to reach the Tre end point of 39.5°C was significantly longer during SH compared to FH (87.2±0.01 min vs. 41.5±0.01 min, p<0.05). A significantly greater postexercise reduction in MAP was measured following SH (-10.8±2.8 mmHg) as compared to FH (-5.0±1.1 mmHg) (p<0.05). This was paralleled by a greater elevation in heart rate (148±6 bpm vs. 137±5 bpm, p=0.07) and reduction in PV (-6.7±1.0% vs. -4.9±1.1%, p=0.09) following SH compared to FH. Core cooling rates did not differ between groups, averaging 0.23±0.02°C/min and 0.24±0.04°C/min for SH and FH respectively. CONCLUSION: We show that differences in the level of cardiovascular strain associated with different exercise-intensity ramping protocols performed to a similar level of thermal strain do not influence core cooling rates during subsequent ice-water immersion. Support: Natural Sciences and Research Council of Canada and Canada Foundation for Innovation (grants held by G.P. Kenny).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".