Testosterone is associated with the cardiovascular autonomic response to a stressor in healthy men
Bibliographic record
Abstract
OBJECTIVE: Men have high cardiovascular risk and unfavourable cardiac autonomic tone compared to premenopausal women. The role of sex hormones in control of autonomic tone is unclear. We sought to determine the association between sex hormones and cardiosympathovagal tone at baseline and in response to a physiological stressor. METHODS: Forty-eight healthy subjects (21 men, 27 premenopausal women) were studied in high-salt balance. Cardiac autonomic tone was assessed by heart rate variability, calculated by spectral power analysis (low frequency (LF, a measure of sympathetic modulation), high frequency (HF, a measure of vagal modulation) and LF:HF (a measure of cardiosympathovagal balance)) at baseline and in response to graded Angiotensin II (AngII) infusion (3 ng/kg/min × 30 min, 6 ng/kg/min × 30 min) were measured. The primary outcome was association between endogenous sex hormone levels and measures of cardiac autonomic tone. RESULTS: All subjects had sex hormone levels in the normal range. No associations were observed between sex hormones and baseline cardiac autonomic tone in men or women. Men with lower testosterone levels, however, were unable to maintain both cardiosympathetic (p = 0.045) and cardiovagal tone (p = 0.035) in response to AngII even after adjustments for covariates. No association was observed between estradiol and progesterone and cardiac autonomic response to AngII in either sex. CONCLUSION: An unfavourable shift in the cardiac autonomic tone in men with lower testosterone levels was observed in response to a stressor. Understanding the role of sex hormones in modulation of cardiac autonomic tone may help guide risk reduction strategies in men.
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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".