Performance and health effects of mild hypoxic hypoxia in simulated 6-hour exposures between 2,438 and 3,048 metres
Bibliographic record
Abstract
Introduction: The Royal Canadian Air Force (RCAF) imposes a daily 4-hour (h)limit for operating unpressurized aircrafts, including helicopters, between 2,438 and 3,048 m (8,000 [8K] and 10,000 [10K] ft) if supplemental oxygen (O 2 ) is unavailable. This regulation may negatively impact RCAF operations because weight and space restrictions limit sufficient O 2 to achieve mission success. The effects of exposure durations beyond the 4-h limit are currently unknown, but extensions have the potential to improve operational effectiveness. This study examined the effects of hypoxic exposures on symptoms, mood and performance as a function of altitude and exposure duration. Methods: Seventeen military helicopter pilots were randomly exposed to two 6-h altitude levels (8K and 9.9K) on 2 separate days in a hypobaric chamber. Daily, participants periodically performed a simulated rotary wing flight task, and completed a cognitive test battery. Cerebral regional and finger pulse oxyheamoglobin saturation levels and heart rate were continuously monitored. Participants indicated their subjective hypoxia signs and symptoms, mood and fatigue. Results: Exposure to altitude significantly decreased cerebral and pulse O 2 saturations, but values remained steady during the 6-h exposure. No negative decrements were observed on cognition or simulation performance. Self-reported symptoms of fatigue and headache were reported at altitude with a slight increase with time. Discussion: No clear evidence of significant deficits on performance was observed in participants when exposed to mild levels of hypoxia for up to 6 h without supplemental O 2 .
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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".