The effects of fluid absorption and plasma volume changes in athletes following consumption of various beverages

Objective: To verify the hydration effects of ORS on athletes by comparing the degrees of fluid absorption and plasma volume changes following beverage consumption, including ORS. Methods: Thirty-one participants visited the testing laboratory 4 times at 1-week intervals to consume 1 liter of beverage (e.g., water, ORS, and two sports drinks) for 30 minutes on each visit. The urine output was measured 4 times at 1 hour, 2 hours, 3 hours, and 4 hours after beverage consumption. A blood sample was collected 3 times at 1 hour, 2 hours, and 3 hours after beverage consumption. Body weight was measured once in 4 hours after beverage consumption. Results: Body weight change was smaller for ORS than for water, SpD1, and SpD2 (p<0.05). Cumulative urine output in 4 hours was lower for ORS, SpD1, and SpD2 than for water (p<0.05), and it was lower for ORS than for SpD2 (p<0.05). BHI in 4 hours was higher for ORS, SpD1, and SpD2 than for water (p<0.05), and it was higher for ORS than for SpD2 (p<0.05). There was no significant difference in PVC for different beverages at all test times, i.e.., 1 hour, 2 hours, and 3 hours. Conclusion: We evaluated the hydration effects of the consumption of beverages, such as water, sports drink, and ORS in athletes. ORS and sports drinks were more effective than water. A comparison between ORS and sports drinks showed that the result could vary depending on the type of sports drink.