Effect of aerobic fitness on capillary blood volume and diffusing membrane capacity responses to exercise
Bibliographic record
Abstract
KEY POINTS: Endurance trained athletes exhibit enhanced cardiovascular function compared to non-athletes, although it is considered that exercise training does not enhance lung structure and function. An increased pulmonary capillary blood volume at rest is associated with a higher V̇O2 max . In the present study, we compared the diffusion capacity, pulmonary capillary blood volume and diffusing membrane capacity responses to exercise in endurance-trained males compared to non-trained males. Exercise diffusion capacity was greater in athletes, secondary to an increased membrane diffusing capacity, and not pulmonary capillary blood volume. Endurance-trained athletes appear to have differences within the pulmonary membrane that facilitate the increased O2 demand needed for high-level exercise. ABSTRACT: Endurance-trained athletes exhibit enhanced cardiovascular function compared to non-athletes, allthough it is generally accepted that exercise training does not enhance lung structure and function. Recent work has shown that an increased resting pulmonary capillary blood volume (VC ) is associated with a higher maximum oxygen consumption (V̇O2 max ), although there have been no studies to date examining how aerobic fitness affects the VC response to exercise. Based on previous work, we hypothesized that endurance-trained athletes will have greater VC compared to non-athletes during cycling exercise. Fifteen endurance-trained athletes (HI: V̇O2 max 64.6 ± 1.8 ml kg(-1) min(-1) ) and 14 non-endurance trained males (LO: V̇O2 max 45.0 ± 1.2 ml kg(-1) min(-1) ) were matched for age and height. Haemoglobin-corrected diffusion capacity (DLCO), VC and diffusing membrane capacity (DM ) were determined using the Roughton and Forster () multiple fraction of inspired O2 (FI O2 )-DLCO method at baseline and during incremental cycle exercise up to 90% of peak O2 consumption. During exercise, both groups exhibited increases in DLCO, DM and VC with exercise intensity. Athletes had a greater DLCO and greater DM at 80 and 90% of V̇O2 max compared to non-athletes. However, VC was not different between groups during exercise. In contrast to our hypothesis, exercise VC was not greater in endurance-trained subjects compared to controls; rather, the increased DLCO in athletes at peak exercise was secondary to an enhanced DM . These findings suggest that endurance-trained athletes appear to have differences within the pulmonary membrane that facilitate the increased O2 demand needed for high-level exercise.
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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) | 0.003 | 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".