Changes in cardiorespiratory economy in people with atrial fibrillation (AF) attending exercise cardiac rehabilitation
Bibliographic record
Abstract
Abstract Background V̇O2 peak is often reported as a main outcome for cardiorespiratory health, fitness and risk. However it is known that improved V̇O2 peak following exercise training can be influenced by such factors as improved motivation, confidence, exercise mode familiarity and clinical cardiac status (e.g AF) on the day of testing. There are a number of submaximal cardiorespiratory responses used to demonstrate if aerobic endurance/power and cardiac health has truly improved. These include cardiopulmonary/aerobic and metabolic/anaerobic economy, work rate at the ventilatory/anaerobic threshold, V̇E/V̇CO2 slope and oxygen uptake efficiency curve. In core terms a reduced oxygen uptake or expired carbon dioxide represent improved aerobic and anaerobic metabolism economies. These changes in cardiorespiratory economy have been linked with improved performance and health, respsetively in athletic and clinical populations. Purpose The purpose of this study was to perform a retrospective analysis that investigated changes in to cardiopulmonary/aerobic and metabolic economy of people with AF attending cardiac rehabilitation exercise (CR) for 8 – 12 weeks, following accepted North-American and European guidelines. Methods Maximal cardiopulmonary exercise test (CPET) data from previous published studies from 38 patients with atrial fibrillation were retrospectively analysed for two elements during an incremental ramp protocol CPET on a cycle ergometer, including: aerobic economy and anaerobic economy. The former was determined by comparing the pre- (T1) and post (T2)-CR programme CPETs’ total volumes of oxygen (litres; L) consumed during the cycle test up to the peak level attained in T1 and similarly for the total volume of expired carbon dioxide. Results The 38 AF participants were aged (mean (SD)) 57.3 (11.7) yrs (8 female). Respective mean (SD) V̇O2 max increased by 10% from T1 and T2: 2.2 (0.5) to 2.4 (0.7) l.min-1 (p = .003). The respective total oxygen uptake at T1 and T2 were 10.2 (4.5) and 10.3 (5.3) L. (NS; p = 0.69), and similarly for total expired carbon dioxide 10.6 (4.9) and 10.1 (4) L. (NS; p = 0.09). The total respiratory exchange ratios for T1 to T2 were 1.04 (0.2) and 1.00 (0.2) (NS; p = .07). From T1 to T2, 16 (42%) and 18 (47%) participants did demonstrate reductions in total oxygen uptake and expired carbon dioxide, respectively, of 5% or more. Conclusions In this cohort of AF CR exercise participants they demonstrated an expected improved aerobic power following 8 – 12 weeks of exercise. Although there were no statistically significant group improvements in either aerobic or anaerobic metabolism economy, over 40% of these AF participants did demonstrate a 5% or greater improvement in cardiorespiratory/metabolic economy. These results thus suggest this is a topic worthy of further study.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 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) | 0.000 | 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".