Post‐Exercise Oxygen Uptake and Muscle Oxygenation in Pediatric Heart Transplant Recipients
Bibliographic record
Abstract
Pediatric heart transplant recipients (HTR) have reduced exercise tolerance and peak oxygen uptake (VO 2 ) values are 57–73% of age‐predicted norms. Slow post‐exercise VO 2 and muscle oxygenation recovery are related to exercise intolerance. However, despite clear exercise tolerance limitations and post‐exercise fatigue, VO 2 and muscle oxygenation during recovery responses are unknown in this population. Purpose We tested the hypothesis that both post‐exercise VO 2 recovery and muscle oxygenation recovery would be slower after peak exercise in pediatric HTR compared to controls. Methods Five pediatric HTR (mean ± SD age = 10.6 ± 3.0 years) and six healthy controls (age = 11.7 ± 2.7 years) performed cycle ergometry to peak exercise followed by 5 minutes of 20‐W cycle recovery. Pulmonary VO 2 and muscle oxygenation (vastus lateralis tissue oxygenation index, TOI using near infrared spectroscopy) were sampled continuously during exercise and recovery. Data were linearly interpolated to 1‐s intervals, and both VO 2 and TOI data were averaged into 5‐s and 10‐s time bins, respectively. VO 2 recovery data were mono‐exponentially curve‐fitted to yield a recovery time constant (tau). TOI recovery was normalized from 0% (end exercise) to 100% (5 min post‐exercise) and data analyzed at set time points to characterize TOI time course changes (0s, 15s, 30s, 60s, 90s, 120s, 180S, 240s, and 300s). Statistical analyses included independent t ‐tests for VO 2 data and a between‐within (2 × 9, group × time) factorial ANOVA for TOI time course changes. Significance was accepted at p < 0.05. Results Recovery VO 2 tau was significantly slower in pediatric HTR compared to healthy controls (68 ± 17 vs. 47 ± 12 s, respectively; p =0.044). There was a significant group × time interaction for TOI recovery ( p =0.003) where TOI in HTR was significantly lower compared to controls at 15s (8 ± 8 vs. 46 ± 19%; p =0.003), 30s (22 ± 13 vs. 91 ± 31%; p =0.001), and 60s (47 ± 23 vs. 117 ± 36%; p =0.005). TOI was not statistically different between groups by 90s onwards (all p >0.05). Conclusions Post‐exercise VO 2 and TOI recovery are prolonged in pediatric HTR compared to healthy controls. These findings suggest that non‐cardiac factors may contribute to the excessive recovery time following peak exercise in pediatric HTR. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".