Battlefield Airmen use Science to Beat the Heat

By Kim Bowden
711th Human Performance Wing

Of all the threats facing battlefield Airmen and other special operations forces, heat doesn’t typically come to mind; however, heat-related illness is a critical factor for personnel operating in extreme temperatures.

Dr. Reginald O’Hara and his exercise physiology research team at the U.S. Air Force School of Aerospace Medicine, part of the Air Force Research Laboratory’s 711th Human Performance Wing, are working to reduce that heat stress.

“Military personnel exposed to excessive heat for an extended period of time may experience reductions in both physical and cognitive performance,” O’Hara said. “Those reductions could severely limit their ability to carry out their duties during intense ground and flight operations.”

An Air Force-invented cooling sleeve for a water bladder and cooling inserts for a specially designed undershirt are two ways that Dr. Reginald O'Hara and his research team at the U.S. Air Force School of Aerospace Medicine hope to help battlefield Airmen and other special operations forces avoid heat-related illness while in hot, humid conditions. (Courtesy photo)

An Air Force-invented cooling sleeve for a water bladder and cooling inserts for a specially designed undershirt are two ways that Dr. Reginald O’Hara and his research team at the U.S. Air Force School of Aerospace Medicine hope to help battlefield Airmen and other special operations forces avoid heat-related illness while in hot, humid conditions. (Courtesy photo)

Essentially, if battlefield Airmen are working at decreased capacity, the risk of mission failure increases.

Though there are many effective ways to mitigate high temperatures, most are not realistic solutions for the battlefield. For example, most devices are heavy and bulky, adding too much weight for troops to practically carry. What’s more, many require a power source or a means of “re-cooling,” which might not always be available, and they are often too noisy to safely use in the field.

Working under a cooperative research and development agreement with Gawi Healthcare LLC, the USAFSAM team has developed an alternative — a small, lightweight, passive cooling technology. Under the three-year technology transfer collaboration with Gawi, which had acquired the assets of Arctic Ease, USAFSAM hopes to develop and commercialize a variety of hydrogel cooling technologies.

O’Hara and his fellow researchers have started testing two variations of the technology to date. One is an Air Force-invented cooling sleeve or wrap for the water bladder that battlefield Airmen and other special ops forces carry, and one is cooling inserts for a specially designed undershirt.

“The devices act through a form of conduction,” O’Hara said, “transferring heat from the water in the hydration pack bladder or the Airman to the hydrogel.

The team conducted field-based testing of the sleeve to see if it would maintain or even reduce the temperature of the water during extended exposure to high heat and humidity, making it more palatable and thereby encouraging Airmen to drink more and stay hydrated.

“The sleeve was tested during 60-minute marches in 90-degree F temperatures and 40-percent humidity, and it successfully demonstrated a 20-degree drop in drinking water temperature,” O’Hara said. “Subjects drank up to 2 liters more cooled water when compared to non-cooled water.”

Additional test plans include incorporation of quick-dissolve amino acid supplements to enhance hydration, energy and performance during training.

Testing of the shirt inserts had similarly positive results, according to O’Hara. Subjects wearing the special undershirt with cooling inserts experienced lower core body temperatures and significantly lower peak body temperatures after a 70-minute weighted vest treadmill walking test than subjects in the standard undershirt with no inserts.

“During sustained operations, even a few degrees can make a tremendous difference,” O’Hara said. “If these cooling devices can lead battlefield Airmen and other special ops forces to drink more or help keep them from over-heating, the risk of heat stress and other heat-related illnesses goes down. And that means their focus can be on accomplishing the mission.”

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