Immediate exercise hyperemia in humans is contraction intensity dependent: evidence for rapid vasodilation
Bibliographic record
Abstract
We tested the hypothesis that rapid vasodilation proportional to contraction intensity contributes to the immediate (first cardiac cycle after initial contraction) exercise hyperemia. Ten healthy subjects performed single 1-s isometric forearm contractions at 5, 10, 15, 20, 30, 50, and 70% maximal voluntary contraction intensity (MVC) in arm above heart (AH) and below heart (BH) positions. Forearm blood flow (FBF; brachial artery mean blood velocity, Doppler ultrasound), mean arterial pressure (arterial tonometry), and heart rate (electrocardiogram) were measured beat by beat. Venous emptying (measured with a forearm strain gauge) was already maximized at 5% MVC, indicating that increases in contraction intensity did not further empty the forearm veins. Immediate increases in FBF were linearly proportional to contraction intensity from 5 to 70% MVC in AH (slope = 4.4 +/- 0.5%DeltaFBF/%MVC). In BH, the immediate increase in FBF demonstrated a curvilinear relationship with increasing contraction intensity and was greater than AH at 15, 20, 30, and 50% MVC (P < 0.05). Peak changes in FBF were greater in BH vs. AH from 10 to 50% MVC, even when venous refilling was complete (P < 0.05). These data support the existence of a rapid-acting vasodilatory mechanism(s) at the onset of human forearm exercise.
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 | 0.001 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".