Cortisol Responses During a Long Duration Incremental Exercise Protocol in the Heat while Wearing Personal Protective Equipment
Bibliographic record
Abstract
Individuals in occupations that wear personal protective equipment (PPE) are exposed to acute heat stress on a regular basis. There is no research evaluating the effects of rapid and uncompensable core temperature (Tc) acquisition, as which occurs when one is wearing PPE, on rate and magnitude of salivary cortisol appearance. PURPOSE: To determine the effects of rapid and uncompensable (Tc) acquisition on the rate and magnitude of salivary cortisol appearance. METHODS: Fourteen male subjects (33.6 ± 12.1 years) performed an incremental treadmill test to a termination point in a control session (CON) and an experimental session (PPE). Salivary samples were collected using an oral swab stimulated method. Saliva samples were processed and analyzed for salivary cortisol concentration using a highly sensitive enzyme immunoassay. Heart rate (HR), thermal comfort scale (TCS) and thermal sensation (TS) were also recorded at each 0.5°C increase in core temperature (Tc). RESULTS: There were significant differences in time to termination (TTT) (CON = 77.3 ± 12.6 min; PPE = 50.3 ± 6.9 min), pre-exercise HR (CON = 76.8 ± 4.8 bpm; PPE = 86.5 ± 5.1 bpm), post-exercise HR (CON = 161.1 ± 11.9 bpm; PPE = 179.6 ± 6.8 bpm), end-exercise Tc (CON = 38.57 ± 0.3°C; PPE = 39.01 ± 0.3°C), TCS (CON = 3.57 ± 0.6; PPE = 4.63 ± 0.3), and TS (CON = 7.57 ± 0.5; PPE = 8.67 ± 0.3). There was also a 0.04°C/min increase in Tc during PPE and a 0.02°C/min increase in Tc during CON. Significant cortisol results showed a difference in the rate of cortisol appearance (CON = 0.002 μg dL-1 min-1; PPE = 0.018 μg dL-1 min-1). There was a significant difference in mean cortisol values between start of exercise and the end of exercise (p ≤ 0.01). There was also a significant difference (p ≤ 0.05) between magnitude of salivary cortisol values at termination when comparing CON and PPE. CONCLUSION: Rapid and uncompensable Tc acquisition results in an elevated acute cortisol response. This will have implications for individuals who are employed in fields that are exposed to acute heat stress chronically. The acute effects of increased cortisol concentration are a decreased anabolic response, decreased cognitive performance, and decreased mood states. The chronic effects are many, but are mostly related to atherosclerosis development and subsequent cardiovascular disease.
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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 | 0.001 |
| 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".