EFFECTS OF AGE ON THE O2 UPTAKE-MUSCLE DEOXYGENATION RELATIONSHIP DURING RAMP CYCLING EXERCISE
Bibliographic record
Abstract
PURPOSE To investigate the influence of age on the relationship between pulmonary O2 uptake and local muscle deoxygenation. METHODS Five young (Y),(mean age 26±3y), and six older males (O),(mean age68±3y), performed ramp cycling exercise (25W/min) to the limit of tolerance. Pulmonary O2 uptake was measured breath-by-breath. Oxy-(O2Hb), deoxy-(HHb), total (Hbtot) hemoglobin/myoglobin and tissue oxygenation index (TOI) of the vastus lateralis were measured continuously by near-infrared spectroscopy (NIRS; Hamamatsu, NIRO 300). NIRS-HHb data were expressed as a percentage of the maximum increase in HHb during the exercise period (HHb,%max). HHb(%max) and TOI were compared between Y and O at similar submaximal VO2's (1.0, 1.25, 1.50, 1.75, 2.0 L/min). RESULTS VO2max was 2.28 (±0.27) L/min in O and 3.81 (±0.43) L/min in Y. The maximal increase in HHb was similar in O (22 ± 7 μ M) and Y (28 ± 12 μ M). At a given submaximal VO2 the O used a significantly greater proportion of their HHb reserve compared to the Y. For example, at VO2 1.75 l/min, HHB(%max) was 64 ± 19% in O versus 27 ± 6% in Y. The TOI was also significantly lower throughout submaximal exercise in O versus Y. CONCLUSIONS The O showed a similar increase in HHb at maximum exercise as in the Y. Throughout exercise, at a given VO2, the greater HHb and the lower TOI in O compared with Y provides evidence of a lower muscle blood flow throughout exercise in the elderly. Supported by NSERC, Canada
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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".