Endothelial Sensitivity to Exercise‐Induced Shear Rate in Pre‐ and Post‐Menopausal Females and in Males
Bibliographic record
Abstract
BACKGROUND Post‐menopausal females appear resistant to the beneficial effects of exercise on endothelial function. Repeated increases in shear stress are considered important mediators of exercise‐induced improvements in endothelial function. It is therefore possible that endothelial sensitivity to shear stress is reduced in post‐menopausal females, thereby blunting endothelial adaptations to exercise training. The objective of this retrospective analysis was to test the hypothesis that post‐menopausal females exhibit a lower endothelial sensitivity to exercise‐induced shear rate relative to pre‐menopausal females and age‐matched males. METHODS Five pre‐ (48 ± 1 yrs) and fifteen post‐ (65 ± 10 yrs) menopausal females, and five males (67 ± 5 yrs) performed 4‐min rhythmic handgrip exercise bouts. Ten participants (6 post and 6 males) exercised at 20%, 40%, 60% and 80% of maximal voluntary contraction, and 15 participants (5 pre, 9 post and 2 males) exercised at 3 kg, 6 kg and 9 kg. The contraction/relaxation cycle was 2‐sec/3‐sec and each bout was separated by 10 min of rest. Brachial artery diameter and blood velocity were measured using high‐resolution ultrasound and analyzed using edge‐detection software. Endothelial sensitivity to exercise‐induced shear rate was quantified as the slope of the relationship between brachial artery dilation (% change from baseline) and shear rate (in s ‐1 ). RESULTS Baseline diameter was greater in males (4.68 ± 0.55 mm) compared with post‐ (3.24 ± 0.53 mm, p<0.01) and pre‐ (3.55 ± 0.19 mm, p<0.01) menopausal females. The rhythmic handgrip protocols elicited net shear rates that ranged between 38 s ‐1 and 392 s ‐1 . A positive correlation was observed between brachial artery dilation and net shear rate in males (r=0.66, p<0.01), and post‐menopausal females (r=0.38; p<0.01), but not in pre‐menopausal females (r=‐0.25, p=0.36). Endothelial sensitivity to exercise‐induced shear rate did not differ between pre‐ (0.037 ± 0.120 %/s ‐1 )and post‐ (0.069 ± 0.081 %/s ‐1 , p>0.99) menopausal females, between pre‐menopausal females (0.037 ± 0.120 %/s ‐1 )and males (0.027 ± 0.055 %/s ‐1 , p>0.99), or between post‐menopausal females (0.069 ± 0.081 %/s ‐1 ) and males (0.027 ± 0.055 %/s ‐1 , p>0.99). CONCLUSION These results suggest that post‐menopausal females do not demonstrate a reduced endothelial sensitivity to exercise‐induced shear rate compared with pre‐menopausal females as well as with males of similar age.
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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) | 0.002 | 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".