Circadian and sleep-wake dependent regulation of heart rate variability in humans
Bibliographic record
Abstract
Cardiovascular disease is the leading cause of death in high income countries, with maximal risk of acute events between 06:00 and noon. Behavioral changes associated with the sleep-wake cycle were first implicated in the risk clustering of cardiovascular events. The circadian system orchestrates the endogenous 24-hour variation of a variety of biological processes, including within the cardiovascular system. Epidemiological evidence supports the involvement of both circadian and sleep-wake processes in the occurrence of adverse cardiovascular events, but causal pathways are only starting to emerge. The aim of the present thesis was to investigate a possible interaction between the circadian- and sleep-wake-dependent autonomic modulation of the heart by the study of heart rate (HR) and HR variability (HRV). In the first experiment, we found that each vigilance state was associated with a distinct autonomic cardiac balance, and circadian rhythms specific to each vigilance state were observed in HR and HRV. During wakefulness, rapid eye movement (REM) sleep, and sleep-to-wake transitions, maximal shifts toward sympathetic cardiac modulation were observed in the morning, while during non-REM sleep, maximal shifts toward parasympathetic cardiac modulation were observed at night. This interaction of the autonomic cardiac modulation can contribute to the temporal distribution of adverse cardiovascular events. In a second experiment, we studied rotating shift workers before and after a series of consecutive night shifts, and we report deficits in performance, alertness, sleep, and mood associated with circadian misalignment. Furthermore, we report greater shift toward sympathetic cardiac modulation during sleep in the non-adapted group. Circadian misalignment and sleep curtailment thus cause considerable physiological changes in susceptible individuals. Taken together, findings of the current thesis suggest that the circadian regulation of the heart could enhance the risk of adverse cardiovascular events at specific times of day, or following chronic circadian misalignment.
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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 | 0.000 |
| 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".