Bibliographic record
Abstract
The evaporative requirement for heat balance (Ereq; calculated as metabolic heat production minus dry heat loss) is the primary determinant of whole-body sweat rate during exercise in compensable conditions. However, the relative influence of metabolic and environmental heat load on physiological responses at a given Ereq remains unclear. PURPOSE: To assess the thermal and cardiovascular responses during exercise bouts at a similar fixed Ereq but for different combinations of metabolic and environmental heat loads. METHODS: Nine healthy males (46 ± 8 yrs) performed four experimental trials consisting of 75 min of semi-recumbent cycling wherein dry heat exchange and metabolic heat production were monitored continuously with the latter adjusted to achieve a fixed Ereq of 400 W. The respective metabolic heat productions and ambient temperatures for each trial were: i) 442 W and 30°C (439W[30°C]), ii) 391 W and 35°C (391W[35°C]), iii) 317 W and 40°C (317W[40°C]) and iv) 258 W and 45°C (258W[45°C]). Whole-body sweat rate was measured via direct calorimetry. Esophageal (Tes) and mean skin (Tsk) temperatures as well as heart rate (HR) were measured continuously. Mean body temperature (Tmb) and physiological strain index (PSI) were calculated from Tes and Tsk, and Tes and HR, respectively. RESULTS: During exercise whole-body sweat rate was similar between conditions (P=0.48), as was Tmb (P=0.65). In contrast, Tes was greater in 439W[30°C] (37.67 ± 0.04°C) and 391W[35°C] (37.58 ± 0.07°C) relative to both 317W[40°C] (37.35 ± 0.06°C) and 258W[45°C] (37.20 ± 0.07°C; all P≤0.05). However, Tsk was different between all conditions (33.85 ± 0.16, 34.53 ± 0.08, 35.67 ± 0.07 and 36.54 ± 0.08°C for 439W[30°C], 391W[35°C], 317W[40°C] and 258W[45°C], respectively; all P<0.01). HR was greater in 439W[30°C] (107 ± 3 beats·min-1) in comparison to both 317W[40°C] (103 ± 4 beats·min-1) and 258W[45°C] (89 ± 2 beats·min-1; both P<0.01) whereas PSI was elevated in 439W[30°C] and 391W[35°C] compared with 317W[40°C] and 258W[45°C] (all P≤0.04). CONCLUSIONS: While exercise performed at a fixed Ereq resulted in similar whole-body sweat rates and Tmb, physiological responses (i.e. Tes, Tsk, HR and PSI) varied as a function of the relative contribution of metabolic and environmental heat load. Supported by Ontario Ministry of Labour and NSERC
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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 | 0.002 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.009 |
| Scholarly communication | 0.005 | 0.007 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.020 | 0.003 |
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".