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Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat.
Appl Physiol Nutr Metab 2010; 35(6):834-41AP

Abstract

We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg-1·min-1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%-65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L-1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (-0.45% ± 0.68% body weight in W, -0.66% ± 0.50% body weight in FW, and -0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance.

Authors+Show Affiliations

Children's Exercise and Nutrition Centre, McMaster University, Hamilton, ON L8N 3Z5, Canada.

Pub Type(s)

Clinical Trial
Comparative Study
Controlled Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21164555

Citation

Wilk, Boguslaw, et al. "Voluntary Fluid Intake, Hydration Status, and Aerobic Performance of Adolescent Athletes in the Heat." Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquee, Nutrition Et Metabolisme, vol. 35, no. 6, 2010, pp. 834-41.
Wilk B, Timmons BW, Bar-Or O. Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat. Appl Physiol Nutr Metab. 2010;35(6):834-41.
Wilk, B., Timmons, B. W., & Bar-Or, O. (2010). Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat. Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquee, Nutrition Et Metabolisme, 35(6), pp. 834-41. doi:10.1139/H10-084.
Wilk B, Timmons BW, Bar-Or O. Voluntary Fluid Intake, Hydration Status, and Aerobic Performance of Adolescent Athletes in the Heat. Appl Physiol Nutr Metab. 2010;35(6):834-41. PubMed PMID: 21164555.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat. AU - Wilk,Boguslaw, AU - Timmons,Brian W, AU - Bar-Or,Oded, PY - 2010/12/18/entrez PY - 2010/12/18/pubmed PY - 2011/3/16/medline SP - 834 EP - 41 JF - Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme JO - Appl Physiol Nutr Metab VL - 35 IS - 6 N2 - We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg-1·min-1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%-65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L-1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (-0.45% ± 0.68% body weight in W, -0.66% ± 0.50% body weight in FW, and -0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance. SN - 1715-5312 UR - https://www.unboundmedicine.com/medline/citation/21164555/Voluntary_fluid_intake_hydration_status_and_aerobic_performance_of_adolescent_athletes_in_the_heat_ L2 - http://www.nrcresearchpress.com/doi/full/10.1139/H10-084?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -