No Sex Differences In Diaphragmatic Fatigue When Matched For Absolute Force During Inspiratory Pressure-threshold Loading
Bibliographic record
Abstract
It has recently been demonstrated that women experience an attenuated cardiovascular response to inspiratory pressure-threshold loading (PTL). Furthermore, due to a significantly longer time to task failure, the rate of development of diaphragmatic fatigue (DF) is slower in women compared to men. It is unclear if the abovementioned differences are due to discrepancies in absolute diaphragm force output. PURPOSE: To examine sex differences in DF when matched for absolute diaphragmatic pressure during inspiratory PTL. METHODS: Fourteen healthy men (n= 6) and women (n= 8) performed a single bout of PTL for five minutes. Subjects were required to breathe in a square-wave fashion whilst targeting a transdiaphragmatic pressure (Pdi) of 92 cm H2O. Fatigue of the diaphragm was assessed via twitch Pdi (Pdi,tw) using cervical magnetic stimulation. Cardiovascular responses, including heart rate (HR) and mean arterial blood pressure (MAP) were monitored beat-by-beat throughout PTL. RESULTS: Following inspiratory PTL, the total work done by the diaphragm (~13,500 cm H2O·s, p= 0.50) and the reduction in Pdi,tw was not different between sexes (M = 26 ± 8%, W = 25 ± 9%; p= 0.82). When scaled to body mass, women produced more diaphragmatic pressure (M = 38 ± 7 cm H2O·s·min-1·kg-1, W = 45 ± 8 cm H2O·s·min-1·kg-1;p= 0.01). There was no effect of sex on Δ HR (M = +14 ± 12 bpm, W = +15 ± 9 bpm; p= 0.50) during PTL; however, Δ MAP was lower in women compared to men (M = +31 ± 16 mmHg, W = +21 ± 13 mmHg; p= 0.03). CONCLUSION: Inspiratory PTL matched for absolute diaphragmatic work results in a similar degree of DF between sexes. Despite performing the same level of absolute diaphragmatic work and developing the same degree of DF, women demonstrate an attenuated inspiratory muscle metaboreflex. Sponsor: Natural Sciences and Engineering Research Council of Canada, UBC Physical Activity and Precision Health Cluster
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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) | 0.005 | 0.001 |
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".