The effect of beverage composition on exercise-induced voluntary dehydration in adolescents
This study examined the effects of beverages containing various concentrations of sodium on fluid balance in children during exercise in a thermoneutral environment (22°C). Hypotheses were that the ingestion of chicken noodle soup prior to exercise would cause: (1) increases in ad libitum drinking throughout exercise, (2) increases in urine osmolalities, and (3) decreases in urine volumes. Forty-five minutes after 12 children ingested water (0 mmol/L Na+), a carbohydrate-electrolyte beverage (16 mmol/L Na+), condensed chicken noodle soup (167 mmol/L Na+), or dehydrated chicken noodle soup (148 mmol/L Na +) the subjects completed 4 bouts of cycling at ~55% VO2 peak for 20 minutes followed by 10 minute rests. Urine volumes were greater in water and carbohydrate-electrolyte trials. Urine osmolalities were greater in soup trials. Ingestion of chicken noodle soup prior to exercise-induced dehydration led to decreases in urine volumes and increases in urine osmolality, suggesting tendencies of improved water retention.