Changes In Circulating Immuno-inflammatory Mediators Following Repeated Exertional Heat Stress Exposures In Untrained Males
Bibliographic record
Abstract
Repeated exposure to hot environments is accompanied by a number of physiological adaptations, including improved thermoregulatory mechanisms which reduce physiological strain within the body and improve heat tolerance during subsequent exertional heat stress (EHS) exposures. To our knowledge, minimal data exists examining the relationship between circulating immuno-inflammatory mediators and the improvements in physiological heat tolerance accompanying repeated EHS exposures. PURPOSE: To examine the immune-inflammatory responses in untrained males following repeated EHS exposures and their relationship to classical physiological adaptations. METHODS: Nine sedentary males (Age = 27 ± 2 years, = 52 ± 2 mL·kgLBM-1·min-1, 17 ± 2% body fat) walked to exhaustion (Exh) at 4.5 km·h-1 with 2% elevation in a climatic chamber (40°C; 30% R.H.) while wearing encapsulating protective clothing for 9-days. Whole blood venous samples were collected at baseline (B) and Exh on Days 1 and 9 and analyzed by ELISA for circulating concentrations of IL-6, IL-1ra, nitric oxide (NO), soluble (s)CD14 and c-reactive protein (CRP). RESULTS: Repeated exertional heat stress exposure produced significant reductions in HR (142 ± 4 vs. 154 ± 4 b·min-1) and an increased time to Exh (145 ± 13 vs. 95± 8 min) on Day 9 compared to Day 1, respectively. No changes were observed in core temperature at B (36.7 ± 0.1 vs 36.6 ± 0.1 °C, p = 0.63), while a tendency for an increased core temperature tolerated at Exh (38.8 ± 0.1 vs 39.1 ± 0.1°C, p = 0.06) was observed between Days 1 and 9. Significantly elevated basal levels of sCD14, as well as tendencies for increased CRP (p = 0.06) and IL-1ra (p = 0.17), were observed on Day 9 compared to Day 1. During EHS, a significant increase in IL-6 (p = 0.01) and a tendency for enhanced NO production (p = 0.10) accompanied improved thermoregulation on Day 9. CONCLUSIONS: These findings suggest that classical thermoregulatory adaptations may be linked to immuno-inflammatory modulation following repeated EHS exposures, contributing to thermoregulatory adaptations and conferring enhanced cytoprotection for a given level of thermal strain. Funded by DRDC Technology Investment Fund and US Office of Naval Research.
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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 | 0.000 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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 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".