Exertional inspiratory capacity and operating lung volumes in health: a population-based study
Bibliographic record
Abstract
Rationale Inspiratory capacity (IC) should increase during exercise to allow unrestrained tidal volume expansion, mitigating uncomfortable respiratory sensations. However, preliminary evidence suggests that this is not universally seen in healthy individuals. Whether this negatively impacts on inspiratory reserves and dyspnoea remains unclear. To gain novel insights on the regulation of operating lung volumes in community-dwelling individuals, we determined the association of a lack of increase in IC during incremental cardiopulmonary exercise testing (dynamic inspiratory capacity (IC dyn )) with demographic, anthropometric and respiratory functional data in a large population-based study. Methods We reviewed general characteristics, pulmonary function and cycle ergometer data from 1065 healthy individuals (51.5% women, aged 20–86 years) with normal lung function. Measurements and main results IC dyn remained unchanged or decreased from rest to peak exercise (Δ (peak–rest) IC dyn ≤0 L) in 245/1065 individuals (23.0%). Tidal volume increased to a lower extent after the ventilatory threshold compared to earlier exercise in these subjects; thus, peak end-inspiratory lung volume (EILV) and EILV/total lung capacity were similar to subjects showing IC dyn >0 L despite higher EILVs. Albeit statistically significant, between-group differences in peak dyspnoea scores were modest (p=0.049). Multivariable regression revealed that age (particularly in women), higher body mass index and higher resting airway resistance were independently associated with ΔIC dyn ≤0 L (p<0.001). Conclusions Elderly women and overweight/obese individuals may fail to increase IC dyn during incremental exercise due to dynamic hyperinflation. Careful regulation of tidal volume, however, avoids critically high inspiratory constraints and limiting exertional dyspnoea.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".