Respecting Cold Through Preparation

With more than ten years of research and advanced knowledge of clothing biophysical properties, Dr. Xiaojiang Xu, biophysical mathematical modeler with the Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), unit of the U.S. Army Medical Research and Development Command (USAMRDC), is developing a user-friendly computer application noting specific clothing items Warfighters should wear based on environmental conditions and planned activity levels. The Cold Weather Ensemble Decision Aid (CoWEDA) app uses a series of inputs to make recommendations to reduce the risk of hypothermia and frostbite.

By Carey Phillips, USARIEM

From Combat & Casualty Care , August 2022

Are you dressed warmly enough? This is a question you’ve no doubt heard millions of times as the season turns cold. For Warfighters operating in cold-to-extreme-cold environments, however, knowing the answer to this question — that is, what to wear in relation to the specific environmental conditions – can go a long way to reducing risk of serious illness and potential injury.

Warfighters, of course, deploy around the world – including to regions featuring sub-zero temperatures. As such, Warfighters need to know exactly which clothing items to wear in those environments so they can, in turn, more safely and more effectively accomplish their mission. Knowing what to wear is far more complicated than dressing for work; it is the first step in creating and maintaining a ready and resilient force.

“How does a Soldier select the clothing they need when they go into cold environments?” said Dr. Xiaojiang Xu, biophysical mathematical modeler with USARIEM, noting that current evaluation of cold weather ensembles is often based on anecdotal experiences, or even simple charts and tables, none of which fully address the need for cold protection. “CoWEDA integrates physiology knowledge, a thermoregulatory model, and a database and algorithms of clothing biophysical properties into a single user-friendly software application. The app has to be user-friendly, and requires no scientific knowledge to use it. That was the starting point.”

Proactive Readiness to Avert Consequence

Cold weather injuries such as hypothermia or frostbite can be severe, life-changing and fatal – but most importantly, such injuries are preventable. There are more than 500 cold-weather injuries reported by Warfighters each year. The CoWEDA app improves Warfighter awareness of their operating environment, and further provides guidance on how to dress appropriately to reduce the risk of cold-weather injury.

“What I hope is that this app can reduce that number,” Xu said of the aforementioned injuries. “If you head into cold-weather environments and you don’t prepare, you will be in trouble; once you’re outside in the cold, there’s really not much you can do anymore. That is the purpose of the app – to tell people about potential danger and prepare them.”
Notably, CoWEDA allows Warfighters to build their own ensembles from their current clothing inventory. Based on user inputs, the app provides clothing recommendations for each of the five body regions: head, upper body, hands, lower body and feet. CoWEDA then interprets those selections in terms of cold injury risk and safe operation times, letting the Warfighter know when exposure to each body part becomes critical. Clothing performance is evaluated by the requirements to prevent frostbite, prevent hypothermia and avoid excessive sweating.

“We have figured out a way to connect a selected clothing item to the physiological consequence,” said Xu. “For instance, different gloves could mean the difference between comfort or pain in the same cold condition. CoWEDA directly relates a selected clothing item to the physiological response so the user knows what will happen if they don’t wear proper clothing. When the hand temperature drops in the cold then the hand will feel cold, pain, numbness and lose the capability to perform different tasks. They will know what kind of clothing they will need to avoid injury or pain.”

To that end, Xu notes his team has been working with clothing manufacturers for several years, asking questions that relate to a given piece of clothing’s performance and capability in extreme temperatures.

“What is the definition of good or not good?” said Xu. “The existing methods are not good enough to present the protection level an ensemble provides. Our team figured out a human-centric approach to evaluate the performance of the cold weather ensemble. The thermal performance of cold ensembles were defined as endurance times instead of insulation values to represent the protection level an ensemble provides.”
Clothing supports and is meant to protect people from cold-weather injury. Cold-weather injuries can have different forms (including frostbite or hypothermia, for instance) but all are serious.

“We have worked out a way to evaluate the performance of cold-weather ensembles,” Xu said. “If the existing methods of cold weather ensemble evaluation are limited and provide incomplete guidance for determining clothing items and preventing cold injuries then how would the individual know what clothing to choose?”

Indeed, this is where the idea of developing such an app came from; the ultimate goal being to provide the individual user with a method to understand which particular clothing ensemble will provide the best protection against cold injuries while also avoiding overheating during exercise in different cold-weather environments.

Practice Equals Preparedness

In 2021, the team provided the CoWEDA app to the 4th Brigade Combat Team (Airborne), 25th Infantry Division to help prevent cold weather injury during the Arctic Warrior 21 Exercise at Joint Base Elmendorf-Richardson in Alaska. During the exercise, weather conditions ranged from negative five degrees to negative 40 degrees Fahrenheit. In the end, data collection showed the CoWEDA had a substantial positive impact; according to recently-published research, the app predicts both the risk of frostbite and hypothermia, and ensures that a selected clothing ensemble is, indeed, appropriate for expected weather conditions and activities.

Due to the success of the computer-based testing, the app has been pushed to USAMRDC’s U.S. Army Medical Materiel Development Activity’s Warfighter Health, Performance, and Evacuation Project Management Office to convert it for access on smartphones. Once the smartphone version is ready, the CoWEDA app will be tested in units working in and deploying to cold-weather environments.

CoWEDA is designed to supplement information found in the Army Technical Bulletin – Medical 508, entitled, “Prevention and Management of Cold-Weather Injuries.” The TB MED 508 provides guidance for cold-weather conditions to military and civilian healthcare providers. The TB MED includes topics such as how the body responds to the cold, how Soldiers should prepare when deploying to the Arctic and how to mitigate and treat different cold weather injuries.



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