How is living in space like playing in the Super Bowl? Both involve circumstances that cause the body to involuntarily lose water. Astronauts and athletes with low body water can suffer physical performance impairments and can develop symptoms such as headaches, fatigue, muscle cramps, light headedness, disorientation and, in severe cases, loss of consciousness. With crew members living and working now and for years to come aboard the International Space Station, this is a real concern.
A rehydration beverage developed by John Greenleaf, physiologist and former researcher at NASA's Ames Research Center in Moffett Field, Calif., to treat low body water, or hypohydration, in astronauts is now being used to improve human performance under various demanding conditions on Earth.
Astronauts involuntarily lose body water during space missions. Body fluid that is usually pulled towards the feet by Earth's gravity shifts rapidly during spaceflight, moving from the legs into the upper body. This fluid shift increases pressure in the head and torso, and body water loss soon follows. Unless astronauts take countermeasures to restore their body water levels prior to re-entry, they can experience serious symptoms of dehydration when they return to Earth and gravity once again shifts their body fluid downwards.
"We set out to solve the problem of involuntary dehydration for astronauts," said Greenleaf. "Our goal was to improve their performance after descent or during the physically demanding work of extravehicular activity during spaceflight."
For astronauts to rehydrate themselves effectively, they must take in both water and electrolytes--or salts. Both the quality and quantity of electrolytes critically affect how water is absorbed and distributed within the body.
Early in the space program, astronauts were given water and salt tablets--specifically, sodium chloride--with instructions to consume both prior to descent. This approach was unreliable. Some astronauts took only the salt tablets, which worsens dehydration; some only drank the water, which simply is excreted and offers no hydration benefit and an inconveniently full bladder; while others ingested varying proportions of salt and water, which provided less than optimal results.
Water that contains 0.9 percent dissolved sodium chloride--also known as isotonic or normal saline, commonly used for intravenous hydration--contains the right amount of electrolytes for optimal hydration, but is problematic as a consumable rehydration beverage. Not only does isotonic sodium chloride taste bad, ingesting it can cause diarrhea.
To help ensure that astronauts would consume correct proportions of electrolytes and water, Greenleaf developed a pre-mixed beverage that was acceptably palatable. Using bad-tasting isotonic saline as a starting point, Greenleaf replaced half of the sodium chloride with sodium citrate and added a non-caloric sweetener. These modifications eliminated the gastrointestinal side effects associated with drinking isotonic saline, improved the taste, and maintained an optimal amount of electrolytes for rehydration. The NASA rehydration beverage contains no sugar or carbohydrates and is distinctly salty-tasting.
"This is not a recreational beverage for casual drinking," said Greenleaf. "It is optimized for effective hydration rather than flavor."
Clinical studies conducted by Greenleaf and collaborators showed that the NASA formula was superior to other rehydration beverages tested for restoring blood plasma volume in dehydrated individuals and for maintaining blood plasma volume during exercise. Their studies demonstrated that use of the rehydration beverage improved regulation of core body temperature during exertion and, importantly, increased exercise endurance.
Although the cause of hypohydration for astronauts is unique, NASA's rehydration solution is broadly applicable.
Wellness Brands Inc., in Boulder, Colo., licensed the NASA invention in 2009 and is marketing the beverage using the trade name "The Right Stuff" to professional, collegiate and amateur sports teams, endurance athletes and workers such as firefighters and military personnel who perform strenuous physical tasks in hot conditions.
When David Belaga, president and CEO of Wellness Brands Inc. encountered NASA's rehydration technology, he immediately knew that he wanted to develop it into a consumer product.
"I had an 'ah-ha!' moment," said Belaga. "The reason we licensed this rehydration technology from NASA is because of the potent science that shaped the development of the product over a decade of research. It was striking that the rehydration beverage increased athletic endurance by more than 20 percent - beyond any other formula NASA tested."
Although the majority of customers who currently use The Right Stuff are serious athletes or workers who perform particularly strenuous jobs, Wellness Brands is looking into other applications of its product including use by dehydrated, jet-lagged air travelers and those suffering the unpleasant results of over-consuming alcoholic beverages.
In December 2013, Greenleaf was awarded the Federal Laboratory Consortium for Technology Transfer, Far West Region's 2013 award for Outstanding Commercialization Success for the patented water-electrolyte rehydration beverage. In January, Greenleaf's technology also was recognized as the Runner-Up Commercial Invention of the Year and Exceptional Space Act Agreement by NASA's Technology Partnerships Division at Ames.
This development is a piece of the whole, like a touchdown in the Super Bowl of human health concerns while living in microgravity. "I am satisfied that we accomplished what we set out to do," said Greenleaf, now retired. "That is, to develop a solution for the hypohydration problem for astronauts." Regarding the decades he spent as a scientist in the Life Sciences Division at Ames, Greenleaf added, "Getting someone to pay you to engage in your hobby is the secret to happiness. My hobby happens to be human physiology."
by Gianine M. Figliozzi
Space Biosciences Division
NASA Ames Research Center