Physiological and psychological adaptations to 13 days of apnea training in novice apneists
Bibliographic record
Abstract
Trained apneists such as freedivers have an augmented apnea-induced bradycardic response compared to novice apneists. We hypothesized that (1) our short-term apnea training protocol would extend the duration of the easy-going and struggle apnea phases while augmenting bradycardia, (2) central command is the mechanism responsible for augmented bradycardia, and (3) the response to a psychological stressor would be attenuated post-training. 22 participants without previous apnea training underwent 13 days of training, which included daily apneas alongside targeted psychological coaching, with in-lab assessments pre- and post-training. In-lab assessment involved a maximal apnea, static handgrip with post-exercise circulatory occlusion to assess central command, and a Stroop test used as a psychological stressor. Heart rate, blood pressure, oxygen saturation, and muscle sympathetic nerve activity were measured continuously throughout in-lab testing. Overall apnea duration (44 ± 21 vs. 75 ± 33 s, p < 0.001) and struggle phase duration (18 ± 18 vs. 45 ± 34 s, p < 0.001) were increased post-training, while the easy-going phase did not increase (26 ± 12 vs. 30 ± 17 s, p = 0.329). The bradycardic response during in-lab apneas was larger post-training (−10 ± 11 vs. −20 ± 13 bpm, p < 0.001). No difference in the heart rate response to handgrip was found post-training (19 ± 15 vs. 16 ± 12 bpm, p = 0.122). The heart rate response to the Stroop test was attenuated post-training (10 ± 7 vs. 6 ± 5 bpm, p = 0.009). The lack of attenuated heart rate response to handgrip indicates decreased central command signalling is not the mechanism responsible for augmented apnea bradycardia. Stroop test results highlight an improved response to a psychological stressor.
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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 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".