Effects of Long Term Exercise on Cardiac Hemodynamic and Contractility Measures in Aging Rats
Bibliographic record
Abstract
Pressure‐volume (P‐V) analysis is a robust approach for the study of in‐vivo ventricular function. In this study, we characterized P‐V alterations that occur with advanced age, with and without long‐term exercise training. Adult (24 month) male Fischer 344 x Brown Norway (FBN) rats were randomly divided into 3 groups; high intensity exercise (HI), moderate intensity exercise (MI), and sedentary (S). MI and HI animals trained at 13 m/min for 30 min/day, with the HI group at 5% incline. Animals were trained daily for 12 months until 36 months of age. Hemodynamic measurements were conducted via a P‐V catheter in the left ventricle (LV) in 36‐month old animals. As a result of the exercise training, rats in the MI group had significant increases (compared to S) in indices of contractility such as End Systolic Pressure‐ Volume relationship (ESPVR), and dP/dtmax. HI animals showed no such improvement and, in fact, had decreases in resting cardiac parameters such as stroke volume, cardiac output, stroke work, and ejection fraction, when compared to MI and S animals. End‐ Diastolic Pressure‐Volume Relationship (EDPVR) was higher in S compared to MI and HI groups. We conclude that long‐term exercise training altered cardiac function in aged hearts but that the response is dependent on exercise intensity. Supported by: NIH AG030423
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| 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".