The Effect Of An Antioxidant Cocktail On Flow-Mediated Dilation In Endurance Athletes
Bibliographic record
Abstract
Flow-mediated dilation (FMD) is a measure of endothelial function, and an FMD response can be initiated by different blood flow induced shear stimuli (e.g. sustained vs. transient exposure), each testing a different aspect of endothelial function. Excessive reactive oxygen species (ROS) are known to impair FMD, but low levels of ROS may be involved in endothelial cell signaling. Endurance exercise bombards the endothelium with ROS and may induce an adaptive response in the endothelium of trained individuals. However, it is unknown whether ROS are involved in the FMD response among endurance trained athletes. PURPOSE: To identify the involvement of ROS in the FMD response of trained endurance athletes to a variety of shear stimuli. METHODS: 10 trained runners and cyclists (n =3 women) performed an incremental exercise test and two experimental FMD visits. An antioxidant cocktail (AOC) or inactive placebo was given prior to each experimental visit (1 g vitamin C, 600 IU vitamin E, 600 mg alpha lipoic acid). Each identical experimental visit involved 3 FMD tests. FMD was measured as reactive hyperemia (RH)-FMD (transient stimulus), sustained stimulus (SS)-FMD (6-min of 9 kg rhythmic handgrip squeezing), and progressive (p)-FMD (rhythmic handgrip squeezing at 3, 6, and 9 kg). RESULTS: Mean VO2max was 58 ± 5 ml∙kg-1∙min-1. Within each FMD method (RH-, SS-, and p-FMD) shear rate was not different between AOC and Placebo (all p > 0.4). SS-FMD was not altered by AOC (PLA = 2.3 ± 1.0 mm, AOC = 2.6 ± 1.6 mm, p = 0.44), and the FMD/shear rate slope created using p-FMD was not altered by AOC (PLA = 0.018 ± 0.002 mm∙s, AOC = 0.017 ± 0.001 mm∙s, p = 0.78). There was a trend for a reduction in RH-FMD following AOC consumption (PLA = 3.1 ± 0.8 mm, AOC = 2.5 ± 1.4 mm, p = 0.08), and the RH-FMD response to AOC was significantly different from the SS-FMD response to AOC (p = 0.04). Following covariance for baseline diameter, SS-FMD (p = 0.003) and RH-FMD (p = 0.04) were significantly reduced following AOC consumption, and there was a trend for a difference in response to AOC between methods (p = 0.06). CONCLUSIONS: These preliminary data suggest that ROS may be involved in the FMD response of trained endurance athletes, and the degree of involvement may vary based on shear stress stimulus. NSERC, CFI, ERA-OMRIS.
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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) | 0.001 | 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) | 0.002 | 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".