Reduced submaximal exercise performance in COPD patients at moderate altitude (2590m)
Bibliographic record
Abstract
Background Chronic obstructive pulmonary disease (COPD) is associated with exercise intolerance at sea level and further limitations are expected at altitude. We quantified exercise performance of COPD patients travelling to moderate altitude and analyzed responsible mechanisms. Methods 37 patients with COPD, (mean±SD FEV1 54±15%) performed submaximal, constant-load bicycle spiroergometry to exhaustion in Zurich (490m) at 60% of maximal work rate (63±30watts), and on the 2nd day after arrival at Davos Jakobshorn (2590m). Performance was compared between altitudes. Results At 2590m exercise endurance was reduced by 57%, and this was associated by a reduced oxygen uptake and PaO2 compared to 490m. Results of exercise tests 490m 2590m Rest End Rest End Exercise duration,sec 471[230;734] 205[135;309]¶ VO2,l/min 0.3±0.1 1.1±0.5* 0.3±0.1 0.9±0.4*¶ VE,l/min 13±3 43±15* 14±3‡ 47±16*¶ Heart Rate,1/min 79±10 119±16* 83±11‡ 119±15* pH 7.42±0.03 7.37±0.09* 7.44±0.03‡ 7.41±0.05*¶ pCO2,kPa 5.5±0.6 5.7±0.9 5.0±0.5‡ 4.8±0.7*¶ pO2,kPa 9.0±1.3 7.5±1.3* 7.0±1.1‡ 6.0±1.0*¶ Means±SD and median[quartiles];*p<0.01 vs. Rest at corresponding altitude;‡p<0.05 vs. Rest 490m;¶p<0.05 vs. End 490m;VO2=Oxygen uptake;VE=Minute ventilation Conclusion In COPD patients, exposed to hypobaric hypoxia at 2590m submaximal exercise endurance was reduced by more than half compared to 490m. The exercise limitation at altitude was related to hypoxemia due to low barometric pressure but not to ventilatory limitation. Grant:Swiss National Science Foundation.
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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 | 0.000 |
| 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".