Effect of fluid temperature on the relation and agreement between perceptual and physiological strain during simulated work in a hot environment
Bibliographic record
Abstract
Cold fluid ingestion is recommended during work to maintain hydration status and physiological function. While monitoring the physiological strain index (PSI) during work in the heat is recommended, it is logistically challenging. Subjective estimates, i.e., perceptual strain index (PeSI), are thought to reflect PSI. However, it remains unclear if cold fluid influences an individual's perception of heat strain. Twenty young adults (10 females) performed four 15-min bouts of moderate-intensity (200 W/m 2 ) cycling in the heat (40°C, 13% RH), each separated by 15-min rest. On separate days, participants consumed 2 boluses consisting of 5.2 g/kg of cold (0°C) or warm fluid (37.5°C) before the first and third work bout. Rectal temperature (Tc) and heart rate (HR) were recorded to calculate PSI (0–10 scale). Rating of perceived exertion (RPE) and thermal sensation (TS) were recorded to calculate PeSI (0–10 scale). Tc, HR, TS, and RPE were compared between experimental trials and across work bouts via two-way ANOVAs. Relation between PSI, PeSI and fluid temperature were evaluated via linear mixed models. Mean bias (95% limits of agreement [LoA]) between PSI and PeSI was assessed via Bland-Altman analysis. Tc, HR, TS and RPE were not influenced by fluid temperature (P ≥ 0.09), nor was the relation between PeSI and PSI (P = 0.11). Mean bias [95% LoA] between PSI and PeSI was greater in cold (−2.1 [-5.7 – 1.5]) compared to the warm fluid condition (−1.8 [-4.8 – 1.2], P = 0.008). While the relation between PeSI and PSI was not influenced by beverage temperature the agreement between measures was worsened following cold fluid ingestion. • Cold fluids (10.4 g/kg) do not reduce core temperature or heart rate during simulated work. • Similarly, cold fluids did not influence perceived strain • Agreement between physiological and perceptual strain was worse after fluid ingestion • Cold fluids worsen the agreement between physiological and perceptual strain.
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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 | 0.000 | 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) | 0.000 | 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".