Bed Rest and Hypoxic Exposure Affect Sleep Architecture and Breathing Stability
Bibliographic record
Abstract
Objective Despite over 50 years of research on the physiological effects of sustained bed rest, data characterising its effects on sleep macrostructure and breathing stability in humans are scarce. This study was conducted to determine the effects of continuous exposure to hypoxia and sustained best rest, both individually and combined, on nocturnal sleep and breathing stability. Methods Eleven participants completed three randomised, counter-balanced, 21-day trials of: (1) normoxic bed rest (NBR, PIO2=133.1±0.3), (2) hypoxic ambulatory confinement (HAMB, PIO2= 90.0±0.4) and (3) hypoxic bed rest (HBR, PIO2= 90.0±0.4; ~4,000 m equivalent altitude). Full objective polysomnography was performed at baseline, on Night 1 and Night 21 in each condition. Results In NBR Night 1, more time was spent in light sleep (10±2%) compared to baseline (8±2%; p=0.028); Slow-wave sleep was reduced from baseline in the hypoxic-only trial by 18% (HAMB Night 21, p=0.028) and further reduced by 33% (HBR Night 1, p=0.010), and 36% (HBR Night 21, p=0.008) when combined with bed rest. The apnoea-hypopnea index doubled from Night 1 to Night 21 in HBR (32 to 62 events∙h-1) and HAMB (31 to 59 events∙h-1; p=0.002). Those who experienced greatest breathing instability from Night 1 to Night 21 (NBR) were correlated to unchanged or higher (+1%) night SpO2 concentrations (R2=0.471, p=0.020). Conclusion Bed rest negatively affects sleep macrostructure, increases the apnoea-hypopnoea index, and worsens breathing stability, each independently exacerbated by continuous exposure to hypoxia.
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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".