Press Release: Economy-class syndrome

The Asahi Shimbun (Evening Edition)
Thursday, February 21, 2002. 4th Edition Page 14
Drinks Containing Electrolytes Prevent Deep Vein Thrombosis
Experiment shows blood flow maintained on direct flight to USA

“Drinks containing electrolytes do a better job than plain water of reducing the risk of deep vein thrombosis in air travelers.” This was the conclusion of a recent experiment conducted by Otsuka Pharmaceutical Co., Ltd. (Chiyoda-ku, Tokyo). Having bought all the economy class seats on a flight to the United States, the company enlisted 40 volunteers to make the journey. The findings were published in the Journal of the American Medical Association (JAMA).

Deep vein thrombosis is often referred to as “economy-class syndrome”, but can also occur on long car and train trips. Last November, the Japan Society of Aerospace and Environmental Medicine (JSASEM) suggested that a less misleading name should be used. Dehydration and restricted blood flow lead to an increase in blood viscosity, and clots formed in the lower body can travel to the lungs and block blood vessels, resulting in breathing difficulty.

The experiment was carried out in May 2001 on 40 male volunteers with an average age of 23.4 years. Two days before the flight departure, the men stayed at a hotel near Narita International Airport where they all ate the same food and consumed the same quantity of water. The volunteers remained seated throughout the nine-hour flight to Washington State, except when giving urine samples. They all ate the same food on-board the aircraft and were given drinks 5 times. Half of the sample group consumed a total 1.3 liters of a drink containing electrolytes while the other 20 men drank the same volume of water.

The men who drank the electrolytic beverage had less need to urinate, even as their blood plasma, which is necessary for maintaining blood flow, increased. “Significant differences” were reported between the two groups, including in the viscosity of the blood in their legs. It is believed that the drink’s ion balance, which is similar to that of the human body fluid, makes it easier for its water content to be absorbed and remain in the body.

JSASEM president Dr. Ichiro Asukata said: “Having observed the effects of fluid intake during an actual flight, we are able to evaluate the results scientifically. We spend long hours sitting in low-humidity environments, even in normal everyday life, such as when we’re working in the office or watching a long play. Moving your legs and drinking something that really keeps you properly hydrated is effective in preventing problems.”