Circadian rhythms in the chemoreflex control of breathing
Bibliographic record
Abstract
Mechanisms underlying the circadian rhythm in lung ventilation were investigated. Ten healthy male subjects were studied for 36 h using a constant routine protocol to minimize potentially confounding variables. Laboratory light, humidity, and temperature remained constant, subjects did not sleep, and their meals and activities were held to a strict schedule. Respiratory chemoreflex responses were measured every 3 h using an iso-oxic rebreathing technique incorporating prior hyperventilation. Subjects exhibited circadian rhythms in oral temperature and respiratory chemoreflex responses, but not in metabolic rate. Basal ventilation [i.e., at subthreshold end-tidal carbon dioxide partial pressure (PET(CO(2)))] did not vary with time of day, but the ventilatory response to suprathreshold PET(CO(2)) exhibited a rhythm amplitude of approximately 25%, mediated mainly by circadian variations in the CO(2) threshold for tidal volume. We conclude that the circadian rhythm in lung ventilation is not a simple consequence of circadian variations in arousal state and metabolic rate. By raising the chemoreflex threshold, the circadian timing system may increase the propensity for respiratory instability at night.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.003 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".