Children Rehydration During Exercise (ROAR)

The low fluid intake in combination with a high intake of sugar-sweetened beverages (SSB) by children is a significant concern among public health professionals. Therefore reformulation of existing commercially available beverages has been suggested as one of the strategies to change SSB beverage behaviors of children. It has been suggested that lack of flavor in plain water is one of the factors of low water intake in children. Therefore, the addition of a flavor to a low-carbohydrate beverage might increase and facilitate the voluntary fluid intake in children, and result in more effective rehydration during and after exercise. The present study aims to examine if a lower sugar flavored water will improve voluntary hydration in children that perform multiple exercise bouts within a period of 3 hours.

Subject will enter a warm room with a temperature between 28-30°C (80-85°F). Then, subjects will undergo a 3-hour walk, cycle, and rest protocol. The exercise intensity is based on 70% of the subject's predicted heart rate using the formula: 220 beats per minute (bpm) - 10 years of age = 210 bpm, and 70% equals 147 bpm). This is an intensity in which the subject has an elevated breathing frequency but can still talk. During the 3-h period subject will complete the following one-hour test three times: 10 min walking on the treadmill at 70% of predicted max heart rate (~147 bpm) 5 min rest 10 min cycling on the cycle ergometer at 70% of predicted max heart rate (~147 bpm) 35 min rest During the 3-h period, subjects will have free access to fluids Body weight and urine samples will be collected during the experiement

Inclusion Criteria: Girls and boys age 8 to 10 years Willing to walk and cycle in a warm environment (80-85°F) Body weight ≤85th percentile for their age group Exclusion Criteria: History of conditions known to alter body water balance (diabetes, renal disease, etc.) Drugs that (may) influence hydration status (including Selective serotonin reuptake inhibitor (SSRI), ADHD medication, diuretics and corticoids) Physical or mental disabilities that would prevent participation in moderate-intensity treadmill walking/jogging and cycling Previous diagnosis of heat stroke Body weight ≥86th percentile for their age group