Comparison Of Salt-, Glycerol- And Salt + Glycerol-Induced Hyperhydration On Fluid Balance In Young Men
Bibliographic record
Abstract
Hyperhydrating before prolonged physical work with limited fluid intake may help maintain or limit the degradation of physiological functions and endurance. Adding sodium or glycerol to a hyperhydration solution optimizes fluid retention, with the former compound being more efficient than the latter. Mechanistically, sodium and glycerol produce their effects by acting on the osmoreceptors and kidneys, respectively. Hence, if added concurrently to a hyperhydration solution, their impact on fluid retention could potentially be greater than their singular effect. PURPOSE: Compare the effects of salt (SIH)-, glycerol (GIH)- and salt + glycerol (SGIH)-induced hyperhydration on fluid balance responses during a 3h hyperhydration protocol. METHODS: Using a randomized, crossover and counterbalanced protocol, 15 young men (22 ± 4 yrs, 63 ± 7 kg fat-free mass (FFM)) underwent three, 3h hyperhydration protocols. During the first 60 min of each trial, they ingested 30 mL/kg FFM of artificially sweetened water with either 1) 7.5 g of salt/L (SIH); 2) 1.4 g glycerol/kg FFM (GIH) or; 3) 7.5 g of salt/L + 1.4 g glycerol/kg FFM (SGIH). Changes in urine production, fluid retention, hemoglobin, hematocrit, plasma volume and abdominal discomfort were monitored throughout the trials. RESULTS: Participants ingested 1885 ± 199 mL (24.9 ± 1.6 mL/kg bodyweight) of artificially sweetened water with either 14.0 ± 1.5 g of salt (SIH), 90.9 ± 8.5 g of glycerol (1.2 ± 0.1 g/kg bodyweight) (GIH) or both (SGIH). After 3h, there were no significant differences among treatments for hematocrit and plasma volume changes (SIH: 11.3 ± 9.9; GIH: 7.6 ± 12.7; SGIH: 11.3 ± 13.7%), but hemoglobin (SIH: 14.3 ± 1.0; GIH: 14.9 ± 1.3; SGIH: 14.5 ± 1.1 mg/dL) was lower with SIH than GIH, with no difference between SGIH and GIH or SIH. Urine production (SIH: 775 ± 329; GIH: 1248 ± 270; SGIH: 551 ± 208 mL) and fluid retention (SIH: 1127 ± 212; GIH: 729 ± 115; SGIH: 1435 ± 140 mL) were significantly different among treatments. Abdominal discomfort was low and not significantly different among treatments. CONCLUSION: Results show that SGIH reduces urine production and improves fluid retention compared with SIH or GIH. These findings may have implications for laborers, military personal and serious but non-competitive athletes since the ingestion of glycerol is prohibited by the WADA.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.001 | 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".