Submaximal breathing reserve during incremental cycle ergometry: reference values and clinical validation
Bibliographic record
Abstract
Background: The interpretation of breathing reserve (BR= [1-ventilation (V̇E)/maximal breathing capacity (FEV1 x 40]/100) at peak exercise (BRpeak) is fraught with complexities in chronic obstructive pulmonary disease (COPD). For instance, BRpeak might be “preserved” (↔) if a dyspneic patient showing a low (↓) BR during submaximal exercise (BRsubmax) interrupts the test due to limiting leg discomfort. Conversely, ↓BRpeak (<15%) may reflect the higher exercise tolerance of less dyspneic patients. Aims: a) to establish the first sex- and age-corrected frame of reference for BRsubmax. and b) to compare how BRpeak and BRsubmax correlate with dyspnea burden and exercise capacity in COPD patients. Methods: Reference ranges for BRsubmax during incremental cycling were established in 277 healthy subjects (133 men, aged 19-85 yrs). BRpeak and BRsubmax were measured in 359 COPD patients (198 men, GOLD stage I-IV). ↓BRsubmax was defined as <5th centile at the highest common submaximal work rate (WR= 40 W). Results: Reference values for BRsubmax were lower in women, decreasing with age in both sexes (p<0.05). One out of three patients (123/359) showed ↔BRpeak:↓BRsubmax: these patients reported the highest leg discomfort/peak WR scores. Higher dyspnea/peak V̇E and lower peak O2 uptake were found in patients with ↓BRsubmax, regardless of BRpeak (p<0.01). Patients showing ↓BRpeak:↔BRsubmax (N=22) had the lowest dyspnea burden and the highest exercise capacity (p<0.05). Conclusions: A novel, readily-available physiological parameter (BRsubmax) is superior to the currently-recommended approach (BRpeak) to identify more dyspneic and physically-limited patients across the range of COPD severity.
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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 | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".