Voluntary Drinking, Body Hydration and Aerobic Performance of Adolescent Male Athletes Running in the Heat
Bibliographic record
Abstract
We have previously shown that beverage flavoring and carbohydrate (CHO) and NaCl stimulate voluntary fluid intake in non-athletic children cycling at a moderate intensity in the heat, thereby preventing dehydration. PURPOSE: This study investigated the effect of beverage flavoring and composition on voluntary fluid intake, body hydration, and aerobic performance in heat-acclimated adolescent male athletes running in the heat at a higher intensity and with much shorter rest periods, than in our previous studies. METHODS: Nine 12- to 15-year-old male cross-country runners (VO2max: 59.2±1.3 mL·kg−1·min−1) underwent at least 4 heat-acclimation sessions (80 min each), followed by three experimental sessions. All sessions were performed at 30°C, 60-65% relative humidity. Each experimental session comprised five 15-min treadmill runs at a speed eliciting 65% VO2max, interspersed by 5 min rest. Ten min after the last treadmill bout, an aerobic performance test (APT - running to exhaustion at a speed eliciting 90% VO2max) was completed. The experimental sessions were identical, except for the beverage that the subjects drank ad libitum: water (W), flavored water (FW), and FW with 6% CHO and 18 mmol·L−1 NaCl (CNa) assigned in a counterbalanced order. Drink intake and body weight (BW) were monitored periodically. RESULTS: Voluntary fluid intake was slightly higher than sweat loss in CNa (1223±111 vs. 1098±91 g), but slightly lower in W (973±129 vs. 1106±89 g) and FW (1063±79 vs. 1113±88 g). Although lower than total fluid losses through sweating, respiration and urine output, voluntary fluid intake during intermittent running was sufficient to prevent major dehydration by the start of the APT (−0.2±0.2 %BW in CNa, and −0.5±0.2 %BW in W and FW). The APT was statistically not different among experimental trials (W: 8.24±0.71 min, FW: 7.45±0.16 min, and CNa: 9.09±0.9 min). CONCLUSION: In contrast to previous findings in non-athletic, unacclimatized boys cycling at a moderate intensity (50% VO2max), heat-acclimated adolescent runners voluntarily consumed enough fluid (irrespective of flavoring and content) to remain well hydrated while running at 65% VO2max in the heat. This likely resulted in similar aerobic performance observed in the W, FW and CNa trials. Supported by Gatorade Sports Science Institute
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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) | 0.000 | 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) | 0.001 | 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".