The Adaptation Of Pulmonary O2 Uptake, Limb Blood Flow, And Muscle Deoxygenation During The Off-transient Of Moderate-intensity Exercise
Bibliographic record
Abstract
During recovery from moderate-intensity exercise the rate of adaptation (i.e., decline) of pulmonary O2 uptake (VO2p) has been shown to be faster than cardiac output suggesting that O2 availability is not a limitation. However, the adequacy of O2 delivery during exercise recovery has not been examined at the level of the working muscle. PURPOSE Off-transient kinetics of VO2p, limb blood flow (LBF) and local muscle deoxygenation (HHb) were determined to investigate the regional balance between muscle O2 delivery and O2 utilization during recovery from moderate-intensity kneeextension (KE) exercise. METHODS Seven adults (27±5 yrs; mean ± SD) performed 3 repeated step-transitions (8 min) from moderate-intensity (MOD; 80% θL) alternateleg KE exercise to passive exercise. VO2p was measured breath-by-breath; LBF was measured via Doppler ultrasound at the femoral artery; and deoxy- (HHb), oxy- (HbO2), and total Hb/Mb (Hbtot) of the vastus lateralis were measured continuously by nearinfrared spectroscopy (NIRS; Hamamatsu NIRO-300). Phase 2 VO2p, LBF and HHb data were fit with a mono-exponential model using non-linear regression techniques. HHb data were fit from the first time point of recovery indicative of an effective τ or mean response time. RESULTS Off-transient phase 2 τVO2p (32±5 s) and τLBF (25±5 s) were not different, however both were faster than the effective τHHb (91±26 s; p < 0.01). CONCLUSIONS The adaptation of conduit artery blood flow and VO2p to a step decrease in work rate at end-exercise were not different. However, the NIRS-derived deoxygenation signal suggests that within the muscle, the decrease in local muscle blood flow relative to local muscle O2 utilization was greater resulting in a very slow return of the HHb signal back to pre-transition levels.
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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) | 0.001 | 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".