The relationship between peripheral endothelial function and cerebrovascular reactivity to CO2 in older adults
Bibliographic record
Abstract
Reduced cerebrovascular reactivity to CO 2 contributes to a higher risk of cerebrovascular events. Studies on healthy and hypertensive middle‐aged adults have suggested the involvement of nitric oxide in CO 2 reactivity based on the relationship observed with peripheral reactive hyperemia. We tested the hypothesis that hyper‐and hypocapnic reactivity is correlated with peripheral vascular endothelial function assessed by flow‐mediated dilation (FMD) in healthy older adults. Methods Blood pressure, heart rate, end‐tidal PCO 2 , middle cerebral artery blood flow velocity (CBFV), as well as brachial artery diameter and shear rate, were monitored in 31 individuals (18 women; 72 ± 5 yrs). CO 2 reactivity was assessed by the relative change in CBFV during hypercapnia (5% CO 2 , 21% O 2 ) and hypocapnia (mild hyperventilation). Peripheral vascular function was measured by the relative brachial artery dilation after 5 min of forearm ischemia. Results Non‐parametric analyses suggested a possible relationship between cerebral and peripheral vascular function, such that a trend was observed between cerebrovascular reactivity and FMD in the hypocapnic range (r s =0.284, p=0.1), but not the hypercapnic range (r s =−0.22, p>;0.1). Conclusion Our study suggests only a weak relationship between peripheral endothelial function and reactivity to hypocapnia in older adults free of cardiovascular disease. Funded by CIHR .
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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 | 0.002 |
| 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 | 0.000 |
| 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".