Thermal Hyperpnea in Humans Changes Following Passive Heat Acclimation
Bibliographic record
Abstract
Introduction Exercise ventilation was shown to increase after a 10‐day, 2 h·day −1 passive heat acclimation (HA) to 50°C and 20 % RH and this study assessed if thermal hyperpnoea for those at rest show a similar adaptation. Purpose It was hypothesized that similar to that seen for eccrine sweating and cutaneous blood flow, the core temperature thresholds for human pulmonary ventilation would decrease after heat acclimation. It was also hypothesized that pulmonary ventilation would increase following heat acclimation as it does for an active heat acclimation. Methods Six male participants performed two 40°C immersions separated by a 10‐day passive heat acclimation. Heat acclimation included 10 consecutive days with participants’ rectal temperatures maintained between 38.5–39.0°C. The heat acclimation was performed in a climatic chamber at 50°C and 20 % RH where participants remained seated at rest for 2 hr·day −1 . A repeated measures ANOVA was employed with factors of Acclimation State (Pre & Post) and delta T ES (0 to 1.4°C from rest). The p value was set at 0.05. An ANOVA with oxygen consumption as the covariate was employed to assess for heat acclimation‐induced changes in pulmonary ventilation. This study was approved by the SFU Office of Research Ethics. Results Acclimation was confirmed by a decrease in resting esophageal temperature (T ES ) from 37.70 ± 0.19 (mean ± SD) to 37.31 ± 0.11°C (p=0.001), as well as by significant decreases in the T ES thresholds for temple cutaneous blood velocity from 37.30 ± 0.12 to 37.07 ± 0.13°C (p=0.014) and for forehead eccrine sweating from 37.60 ± 0.25 to 37.25 ± 0.22°C (p=0.03). The pulmonary ventilation thresholds were 38.28 ± 0.28 before and 37.84 ± 0.44°C after heat acclimation (p=0.13). After accounting for the covariate of oxygen consumption, a significant main effect of Acclimation State (F=10.05, p=0.025) plus an acclimation state x delta T ES interaction for pulmonary ventilation (F=3.6, p=0.008) were explained by a significantly greater pulmonary ventilation following acclimation at delta T ES of 0.6, 0.8, 1.0°C (0.018 Conclusion Following a passive heat acclimation the resting T ES and T ES thresholds for human thermoregulatory responses were significantly lower and pulmonary ventilation was significantly increased during passive heating as indicative of an increased thermal hyperpnea. Support or Funding Information Funding Source This project was supported by Natural Sciences and Engineering Research Council of Canada and the Canada Foundation for Innovation.
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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 | 0.001 |
| 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) | 0.002 | 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".