Researcher Shares Cold Safety Tips for Soldiers

By Christen N. McCluney
Special to American Forces Press Service

Dec. 17, 2009 - Researchers at the U.S. Army Research Institute of Environmental Medicine are coming up with ways to sustain soldiers' performance in environmental extremes, a research physiologist at the institute said today. "Our job is to help [soldiers] do their job better in rough environments," John Castellani told listeners to the "Dot Mil Docs" program on DoDLive.mil.

Hypothermia, frostbite and nonfreezing cold injuries are common in winter and in cold environments, he said. Areas of the body affected by frostbite usually feel cold and firm, and burning, tingling, stinging, or numbing sensations may also be felt, Castellani said. White spots may appear on the skin in minor cases, and more severe cases could cause blistering and tissue damage.

"One of the biggest things is to get out of the environment and to re-warm the tissue," he said. Though the first instinct is to warm the area over a fire or an engine, he added, the best step is to re-warm very slowly to make sure there is no major damage.

Castellani emphasized the need to get out of the environment to prevent major tissue damage from frostbite. "You are better off to allow tissue to remain frozen than to be in an environment where you are in a freeze- thaw -freeze cycle," he said.

Another way soldiers can prevent cold-related injuries is to protect their bodies. "How you dress is the biggest preventive method," Castellani said.

Dressing in layers provides insulation from trapped air. He suggested that soldiers wear a base layer that allows moisture to move through it, rather than cotton, which absorbs sweat. Silk, polypropylene and other synthetics serve as the best materials, he said, because they allow moisture to move away from the skin.

The middle layer should be materials that provide insulation, such as fleece and wool, and the top layer should be windproof and waterproof. Soldiers should use knowledge of layering to create their own number of layers based on their personal preference, he added.

Staying dry is important in preventing cold-related injuries, Castellani said. Getting wet from sweat or rain or wearing wet gloves or boots can cause injuries, he said.

Protecting the skin is also another measure Castellani recommended to stay protected in the cold. Wind chill, the temperature felt on exposed skin due to wind, can get low before seeing an actual frostbite injury. Wind from helicopter rotors and moving downhill in a cold environment need to be taken in to account when protecting the skin, he noted.

Another possible injury is one not usually associated with cold weather. "Sunburn can still happen in the winter, and you can still get sunburn when the UV index is low," Castellani said. Wearing sunscreen is important in a cold environment, he said, because there is always a chance of sunburn from indirect light off snow. "Snow blindness," which he said is sunburn of the eye, is easily preventable by wearing sunglasses or goggles, he said.

Although the cold doesn't change the body's requirements for food and water intake very much, Castellani suggested staying hydrated and listening to your body to know when you may require more food to maintain your energy. Some people burn more calories than usual walking in the snow or carrying extra weight from cold-weather clothing or backpacks, he said.

"When you go to a cold environment, work in it and see how it goes, and then adjust from that," he said.

(Christen N. McCluney works in the Defense Media Activity's emerging media directorate.)