Menstrual Phase Differences In The Physiological Resolution Of Periodic Breath-holding During Heavy Intensity Fartlek Exercise
Bibliographic record
Abstract
PURPOSE: Fluctuations in ovarian hormones have been shown to affect the physiological responses to heavy-intensity exercise. These responses may be exacerbated during backstroke swimming during the underwater push-off phase where swimmers are required to perform breath holds (~5 s) while kicking to the surface. The purpose of this study was to compare the singular and combined effects of repeated cycles of 5 s breath holds (BH) and hi-power output (HPO), every 30 s, during heavy-intensity (HVY) exercise during follicular (FOL) and luteal (LUT) phases. METHODS: Eight eumenorrheic women (22 ± 1 yr, VO2max 2.36 ± 0.4 L⋅min-1) performed four 6-min exercise bouts on a cycle ergometer at a power output of 50 % of the difference between vetilatory threshold and VO2max (α50%) in the FOL and LUT. A continuous HVY (CONT) with free breathing, and 3 intermittent conditions including, repeated cycles of 25 s free breathing and 5 s BH (BH), repeated cycles of 25s at α50% and 5s at peak aerobic power (HPO) and combining the BH and HPO (BH-HPO) perturbations were performed. Gas exchange and vastus lateralis deoxygenation (HHb) were recorded during all trials. RESULTS: Mean Ventilation (VE) and total [hemoglobin] were higher in all conditions during LUT vs FOL (LUT 78.0 ± 10.7; FOL 75.1 ± 10.7 L⋅min-1 and FOL: 2.0 ± 2.2 μMol; LUT: 2.9 ± 1.9 μMol respectively p<0.05). Carbon dioxide production (VCO2) was higher during LUT BH-HPO (LUT: 2.41± 0.18 L⋅min-1; FOL: 2.19 ± 0.24 L⋅min-1p<0.05). Whereas %αHHb was greater during the 5s BH vs the 25s free-breathing period in both LUT (25s: 87 ± 9 %; 5s: 89 ± 8 % p<0.05) and FOL (25s: 86 ± 15 %; 5s: 89 ± 13 % p<0.05) phases. Further, %αHHb/%αVO2 was greater during BH (6%) and HPO-BH (7%) during the 5s BH vs the 25s free-breathing in both phases (FOL: 46.0 ± 18 %; LUT: 45 ± 14 % and FOL: 44 ± 18 %; LUT: 44 ± 15 % respectively p<0.05). CONCLUSION: Low PO2 in the area of investigation (i.e. vastus lateralis) during heavy intensity exercise has been shown to increase CO2 transport by increasing the affinity of CO2 to Hb (Haldane effect). Moreover, the increased pulmonary diffusion capacity during the LUT phase suggested elsewhere would facilitate the observed increase in VCO2 and VE during the BH-HPO protocol of the present study. Finally, females show increased local muscle deoxygenation in both BH conditions during both the FOL and LUT phases.
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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".