Preliminary Characterization of Enterade® Rehydration Kinetics Following Intra- and Extracellular Dehydration

Abstract

Two distinct types of dehydration occur when body water loss is accompanied by small or large solute losses. Small solute losses result in shared water losses between the intra- (ICF) and extracellular (ECF) fluid spaces (intracellular dehydration, ID) while large solute losses primarily reduce volume of the ECF (extracellular dehydration, ED). The distinction between the two has therapeutic implications for rehydration. Enterade® is a commercial beverage blend of amino acids and electrolytes designed to improve gut function and enhance body water restoration. PURPOSE: To compare the rehydration kinetics of Enterade® following two types of dehydration. METHODS: Nine healthy, non-heat acclimatized volunteers participated in this study [mean ± SD; 20 ± 2 yr, 73.3 ± 11.9 kg, 1.8 ± 0.1 m, total body water (TBW), 39.5 ± 7.2 L]. A euhydration baseline was established over three days using standardized fluid intakes (≥3 L/d). On day four volunteers were acutely dehydrated using 80 mg furosemide (ED; n = 6) or exercise-heat stress (ID; n = 3). Volunteers were then rehydrated by replacing 100% of TBW losses with Enterade® over 90 minutes. Blood, urine, and sweat were sampled throughout. Rehydration kinetics were assessed over 4 hours, including plasma volume (PV) restoration, compartmental fluid shifts (Cl- method) and drink volume retention. RESULTS: ID (- 3.8 ± 0.1% body mass) produced a hyper-osmotic (8 ± 1 mmol/kg) hypovolemia (-11 ± 3% PV). Losses in TBW (-2.9 ± 0.7 L) and solute (-535 ± 117 mmol) were shared between the ICF (33%) and ECF (67%). ED (-3.0 ± 0.2% body mass) produced an iso-osmotic (0 ± 2 mmol/kg) hypovolemia (-11 ± 4% PV). TBW (-2.2 ± 0.2 L) and solute losses (-719 ± 98 mmol) came primarily from the ECF (90%). PV was restored to baseline by 30 min in ID and by 60 min in ED, but after 4 hours ID was 5% above baseline while ED was 3.5% below. Enterade® retention was 73 ± 7% in ID and 63 ± 13% in ED. The ICF and ECF were restored by 47% and 88% in ID, while in ED restoration was 113% and 59% for ICF and ECF, respectively. CONCLUSION: Enterade® rehydrated volunteers to within 1% of euhydrated TBW baseline after 4 hours in both ID and ED. However, PV was restored more rapidly and recovery of the ECF volume was more complete in ID. Opinions herein are the private views of the authors; citations of commercial products are not an endorsement by the DOA.