Abstract P3101: Dietary Nitrates Negate Beneficial Cardiac Adaptations To Aerobic Exercise In A Sex-specific Manner
Bibliographic record
Abstract
Dietary supplements such as nitrates are commonly combined with aerobic exercise with the idea that this will improve performance and cardiac function. Whether this combination leads to beneficial effects on cardiac function at the cellular level is unclear, and few studies have used females. We determined whether dietary nitrates and/or aerobic exercise improves fitness and cardiovascular health in adult mice (both sexes) and explored underlying mechanisms. C57Bl/6 mice (9-mos) were given 1mM sodium nitrate (drinking water) and/or access to a running wheel for 3 mos. Cardiac function (echocardiography), blood pressure (tail cuff) and fitness (treadmill) were measured in mice at endpoint; calcium transients (Fura-2) and calcium currents were measured in isolated ventricular myocytes at endpoint. Exercised mice had better fitness and improved cardiac function when compared to sedentary mice, regardless of sex. Nitrates had no effect on blood pressure, total voluntary wheel running, or endpoint fitness measured as distance to exhaustion (242 ± 28 vs 294 ± 37 m, p=0.29; 122 ± 29 vs 136 ± 16 m, p=0.69 in females and males, respectively) compared to exercised controls. However, nitrates combined with exercise impaired cardiac function in a sex-specific manner. Nitrate-treated male mice who exercised had lower E/A ratios (1.8 ± 0.3 vs 1.3 ± 0.1, p=0.01) and thus worse diastolic function than control exercised male mice. By contrast, nitrate-treated female mice who exercised had smaller global longitudinal strain (-19.5 ± 1.5 vs -11.8 ± 3.0%, p=0.01) than control exercised mice, indicative of worse systolic function. Corresponding changes were seen at the cellular level. Male mice given nitrates had slower times to 50% calcium transient decay than controls (44.8 ± 4 vs 73.8 ± 6 ms, p=0.01), while females given nitrates had slower velocity to peak calcium (0.031 ± 0.004 vs 0.018 ± 0.003 μm/ms, p=0.005). These changes in calcium transients were attributable, at least in part, to corresponding changes in calcium currents. Thus, exercise improves fitness regardless of nitrates and promotes beneficial cardiac adaptations in systolic and diastolic function, but these benefits are negated when exercise is combined with dietary nitrates in a sex-specific fashion.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
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".