SPLENIC CONTRACTION, CATECHOLAMINE RELEASE, AND BLOOD VOLUME REDISTRIBUTION DURING EXERCISE IN MAN
Bibliographic record
Abstract
Purpose: To determine the mechanism for splenic volume reduction with exercise and to determine the effect of splenic expulsion of red cells on indirect plasma volume measurements. Methods: 9 males (age = 24.9 ± 1.0, VO2 max = 54.1 ± 2.3 ml.kg−1.min−1) undertook four exercise bouts. Three consisted of cycling at 60% VO2 max for 5, 10, and 15 minute duration, separated by 30 minutes. The final exercise bout was an incremental ride to exhaustion. Spleen imaging was determined using 99m Tc labeled red cells, immediately prior to and following each exercise bout as well as every ten minutes for an hour after the incremental ride. Plasma volume was measured with 125I-RISA pre- and 131I-RISA post-exercise, and 51 Cr was used to measure red cell volume. Plasma catecholamines were collected at rest and every 10 minutes for an hour following the incremental ride and analyzed by high performance liquid chromatography. Results: A significant reduction in spleen volume was observed following the durational rides (pre = 85.8 ± 10.1, post = 59.3 ± 8.1 mls; p < 0.001), however no significant differences were observed in the reduction in spleen volume between the three durational rides. Following the incremental ride to exhaustion the spleen volume was significantly reduced compared with pre-exercise at 0 and 10 minutes of recovery (pre = 85.9 ± 9.93, post 0 min = 36.4 ± 3.95, post 10 min = 61.9 ± 8.51 mls; p < 0.001). Spleen volume was inversely correlated with plasma epinephrine (r = −0.46; p < 0.001) and norepinephrine (r = −0.58; p < 0.001) following exercise. There was no significant difference in red cell or total blood volume pre- to post exercise, however a significant reduction in plasma volume was observed (pre = 46.6 ± 1.44, post = 38.3 ± 1.83 mls.kg−1; p = 0.002). There was no difference between the direct and indirect methods of assessing plasma volume reduction (I-RISA = 18.9 ± 2.41, Hct = 20.6 ± 1.90, Hb and Hct = 19.9 ± 1.83, Hb and Hct with F-cell correction = 17.3 ± 1.75%; p > 0.05). Conclusions: These results suggest that the spleen is capable of contracting in response to an intensity dependent signal and that plasma catecholamines are partially responsible. The release of red cells from the spleen appears to have no effect on indirect measures of plasma volume reduction. Supported by a grant from the British Columbia Sports Medicine Foundation
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".