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February 20, 2002

Effects of Hydration on Fluid Balance and Lower-Extremity Blood Viscosity During Long Airplane Flights

Author Affiliations

Stephen J.LurieMD, PhDIndividualAuthor

JAMA. 2002;287(7):844-845. doi:10.1001/jama.287.7.839

To the Editor: Long airplane flights may be a risk factor for pulmonary embolism,1,2 which may be due in part to mild dehydration from insufficient fluid intake, consumption of diuretic beverages, and low ambient humidity.3 Increased blood viscosity (BV) on long flights also may be associated with dehydration-related hypovolemia, as well as venous stasis from long periods of sitting. Both processes could increase the risk for thrombosis.3 In a simulation of a long airplane flight, the reduction of plasma volume (PV) observed during 10 hours of confinement in a chamber was attenuated by an intake of isotonic-electrolyte solution.4 A combination of electrolytes and carbohydrates could further enhance hydration in this situation.5 We tested the hypothesis that a beverage containing electrolytes and carbohydrates (ECB) would be more effective at maintaining hydration and BV than water alone on a long-distance international flight.