Sex and age interaction in fundamental circulatory volumetric variables at peak working capacity
Bibliographic record
Abstract
Abstract Background Whether the fundamental hematological and cardiac variables determining cardiorespiratory fitness and their intrinsic relationships are modulated by major constitutional factors, such as sex and age remains unresolved. Methods Transthoracic echocardiography, central hemodynamics and pulmonary oxygen (O 2 ) uptake were assessed in controlled conditions during submaximal and peak exercise (cycle ergometry) in 85 healthy young (20–44 year) and older (50–77) women and men matched by age-status and moderate-to-vigorous physical activity (MVPA) levels. Main outcomes such as peak left ventricular end-diastolic volume (LVEDV peak ), stroke volume (SV peak ), cardiac output ( Q peak ) and O 2 uptake (VO 2peak ), as well as blood volume (BV), BV–LVEDV peak and LVEDV peak –SV peak relationships were determined with established methods. Results All individuals were non-smokers and non-obese, and MVPA levels were similar between sex and age groups ( P ≥ 0.140). BV per kg of body weight did not differ between sexes ( P ≥ 0.118), but was reduced with older age in men ( P = 0.018). Key cardiac parameters normalized by body size (LVEDV peak , SV peak , Q peak ) were decreased in women compared with men irrespective of age ( P ≤ 0.046). Older age per se curtailed Q peak ( P ≤ 0.022) due to lower heart rate ( P < 0.001). In parallel, VO 2peak was reduced with older age in both sexes ( P < 0.001). The analysis of fundamental circulatory relationships revealed that older women require a higher BV for a given LVEDV peak than older men ( P = 0.024). Conclusions Sex and age interact on the crucial circulatory relationship between total circulating BV and peak cardiac filling, with older women necessitating more BV to fill the exercising heart than age- and physical activity-matched men.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".