Cycling Efficiency Is Not Compromised for Moderate Exercise in Moderately Severe COPD
Bibliographic record
Abstract
INTRODUCTION/PURPOSE: Hyperpnea and hyperinflation have been proposed as contributors to exaggerated energy demands in chronic obstructive pulmonary disease (COPD), yet there are incomplete data on exercise requirements. This study compared total-body energy demands of the internal (unloaded) and external work of cycling and delta mechanical efficiency in 40 patients (FEV1: 36+/-14% predicted) with COPD and 28 healthy age-matched controls while characterizing dynamic hyperinflation. METHODS: Steady-state V O2 was obtained at rest, during unloaded and 20-W cycling, and at 20, 50, and 65% peak cycling power. Delta mechanical efficiency was calculated between constant-load cycling at 65 and 20% peak power. Dynamic hyperinflation was assessed from inspiratory capacity maneuvers. RESULTS: Oxygen demands (L.min) at rest, for internal work (0.47+/-0.14 vs 0.45+/-0.11) or external work at 20 W (0.62+/-0.20 vs 0.57+/-0.13), were not different between patients and controls, although ventilation was elevated in COPD. Cycling at 65% of peak power induced dynamic hyperinflation in COPD, which indices were not related to cycling efficiency. Delta efficiency (%) was not different between patients (26.3+/-8.1) and controls (24.8+/-4.0). CONCLUSION: Findings suggest that bioenergetics of submaximal cycling is not compromised in moderately severe COPD despite tachypnea and dynamic hyperinflation.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".