SARAH DOBSON
U.S. Army Public Health Center
Aberdeen Proving Ground, Maryland

Cold-weather injuries, or CWIs, affect hundreds of service members each year and have debilitating effects on the human body if they do not take preventive measures. In the Army, injuries resulting from exposure to cold and wet environments reduce force strength and have immediate impacts on Soldier readiness and mission success.

According to the Defense Health Agency Medical Surveillance Monthly Report from October 2017, the Army accounted for nearly 58 percent of all cold injuries diagnosed in active-duty service members during the 2016-17 cold season. Soldiers participating in military training or deployments most often encounter CWIs, which can include hypothermia, frostbite, non-freezing cold injuries (e.g., chilblains, trench/immersion foot) and injuries related to cold exposure. Conditions related to cold exposure include dehydration, carbon monoxide poisoning, sunburn, snow blindness, and slips and falls. In addition to the cold itself, factors such as duration of exposure, humidity, wind and altitude all contribute to CWIs.

Fortunately, CWIs are preventable. Soldiers need to understand the importance of taking cold-weather safety precautions and actively employing injury-prevention strategies with the help of healthcare providers and military leaders. The U.S. Army Public Health Center recommends service members remember the acronym COLD, which serves as an easy reminder for CWI prevention:

Keep it Clean
Avoid Overheating
Wear it Loose and in Layers
Keep it Dry

Soldiers can increase resilience against CWIs through the following prevention methods:
 

• Wear proper clothing. It is essential for Soldiers to keep clothing clean, dry and worn in loose layers. They can remove clothing layers as the ambient temperature or physical activity increases, which can reduce sweating and overheating. To keep feet warm and dry, individuals should wash and dry feet and put on dry socks at least twice a day.


• Keep the body moving. Soldiers must keep major muscle groups moving or at least keep hands and feet warm by moving fingers and toes if unable to walk or exercise. Frequent movement is necessary because it increases blood flow to muscles. Soldiers can warm fingers quickly by swinging their arms in a wide arc from an extended side position to a front position and hitting hands together until warmth is restored. Also consider moving your lips from side to side and up and down to increase blood circulation throughout the face to help prevent cold injury to facial tissue.


• Be mindful of personal risk factors. Military personnel between the ages of 17-25 suffer the most CWIs. Soldiers not acclimated to cold weather and unprepared to survive in winter conditions are likely to suffer from a CWI; however, anyone is susceptible. Female Soldiers should take extra precautions in cold-weather conditions because they sustain peripheral CWIs at a rate two times higher than males of comparable age and weight. Certain medical conditions such as hypothyroidism and Raynaud’s disease can increase cold intolerance. In addition, many medications change the way the body reacts to temperature in the environment, so Soldiers should ask their healthcare provider for information on whether they could be at increased risk for a CWI.


• Stay hydrated. Dehydration increases the chances of hypothermia and frostbite. As with exposure to heat, dehydration occurs easily in cold environments, causing decreased ability to tolerate physical activity and even impaired cognitive function. Drinking hot liquids can help keep the body warm. Soldiers that drink plenty of fluids and maintain a healthy diet will be at lower risk for CWIs.


• Ensure proper nutrition. The body burns calories by maintaining body temperature in extreme hot and cold conditions. Therefore, those exposed to cold environments need to consume more calories than usual and eat well-balanced meals to maintain energy levels and lower their CWI risk. Low blood sugar (hypoglycemia) makes it difficult to generate body heat, and low availability of carbohydrates limits physical activity capabilities. Food also contains electrolytes that are necessary to water regulation in the body.


• Be aware of hazardous conditions. The presence of ice and snow in cold-weather conditions poses a great risk for slips and falls that result in injuries to different parts of the body. These injuries may include sprains/strains and fractures to lower extremities (e.g., legs, ankles and feet) along with wrists and arms.


• Get adequate sleep. To achieve optimal performance, Soldiers should aim to get eight hours of sleep per 24-hour period. Physical fatigue has been shown to impair shivering and physiological responses to cold weather, increasing the risk of hypothermia. Mental and physical fatigue may cause Soldiers to neglect basic cold-weather protection measures.


• Ensure proper ventilation. Carbon monoxide poisoning occurring in cold-weather conditions is serious and life threatening, but preventable. Soldiers should not be permitted to sleep in vehicles while engines are running, tent stoves and heaters must be Army-approved, and sleeping tents must have proper ventilation.


• Protect the eyes and skin. Snow blindness and sunburn result from ultraviolet radiation exposure to unprotected eyes and skin. Snow, ice and lightly colored objects reflect the sun’s rays and increase injury risk. Wearing dark, UV-protective glasses or goggles can help prevent snow blindness. Soldiers can protect against sunburn in cold weather by using an alcohol-free sunscreen that blocks both UVA and UVB rays. Sunburn to the skin increases heat loss during cold exposure, increasing susceptibility to hypothermia, and causes pain that hinders a Soldier’s performance.


• Avoid using alcohol and nicotine. It is important to understand the body’s reaction to alcohol and nicotine in the context of a cold environment. Alcohol consumption produces peripheral vasodilation, gives a false sense of warmth and may impair senses and judgment, which makes it more difficult for a Soldier to detect a CWI. Nicotine causes peripheral vasoconstriction and decreased blood flow to limbs, which increases the risk for CWIs, especially frostbite.


• For anyone working in a cold environment, it is important to balance the amount of time and activity spent outside to reduce the injury risk. Educating Soldiers about the steps needed to minimize the risk of cold injury, especially awareness of personal factors, is key in lowering the number of preventable CWIs.
  
  Sources:
  1. TB MED 508 Prevention and Management of Cold-Weather Injuries (2005). http://www.usariem.army.mil/assets/docs/publications/articles/2005/tbmed508.pdf
  2. Cold Weather Injuries Fact Sheet APHC.
  3. Medical Surveillance Monthly Report, October 2017 https://www.health.mil/Military-Health-Topics/Health-Readiness/Armed-Forces-Health-Surveillance-Branch/Reports-and-Publications/~/link.aspx?_id=534E26BD8E5D4ECC8CAA8ABA47679691&_z=z
  4. Cold Weather Casualties and Injuries (2017). https://phc.amedd.army.mil/topics/discond/cip/Pages/Cold-Weather-Casualties-and-Injuries.aspx
  5. Manage Environmental Cold Injuries. https://www.trngcmd.marines.mil/Portals/207/Docs/FMTBE/Student%20Materials/FMST/111.pdf.
  
  
  Cold Injury Prevention
  
  ■ Immersion foot: This is caused by continued exposure to wet, cold conditions. The surprising factor is it doesn’t have to be freezing cold. Immersion foot can occur at temperatures up to 60 F if the exposure lasts as long as 12 hours. Of course, if the temperature is lower, it can occur sooner. Symptoms include cold, numb feet that may have shooting pains, as well as redness, swelling and bleeding, particularly involving the toes.
  + First Aid: The most important step is to re-warm and dry the feet. Expose the feet to warm air and/or gently wrap in dry blankets or towels. Do not massage, rub or use salves or ointments on the feet. Do not expose the feet to extreme heat; if the feet are numb, the victim may get burned and not realize it. If you suspect trench foot, get medical help immediately.
  
  ■ Chilblain: This is a condition caused by exposure of bare skin to continued temperatures ranging from 20 to 60 F, depending on an individual’s acclimatization. Symptoms of chilblain include tender, hot-feeling, red and itching skin mainly on exposed areas like the cheeks, ears and fingers. Feet, however, also may be affected.
  + First Aid: Warm the Soldier’s affected body part with direct body heat, or move the Soldier to a warm area. Do not massage the area, rub with snow or ice or apply salves or ointments. Do not expose the area to any intense heat. If the Soldier does not improve, seek medical help.
  
  ■ Frostbite: This is a very common and potentially dangerous injury. The body is mainly water, and water freezes at 32 F. Frostbite occurs when the body cannot maintain sufficient internal heat in certain parts and the water in cells freezes. Areas that are most often affected are those areas exposed or where blood flow can be decreased such as fingers, toes, ears and other facial parts. Exposure to bare skin on metal, extremely cool POL, wind chill and tight clothing, particularly boots, can make the problem worse. Symptoms include numbness or tingling in the affected part; blisters, swelling or tenderness; body parts that feel dull or wooden; and pale, yellowish or waxy-looking skin — gray in dark-skinned Soldiers.
  + First Aid: Frostbite is a medical emergency and the victim should be evacuated as soon as possible. If not treated properly, frostbite can lead to gangrene and amputation. Before evacuation, move the Soldier to a warm area and the part affected must be warmed with direct body heat or warm air. Do not warm with hot water or expose the part to intense heat. Do not massage or rub with snow or ice or use salves and ointments on the affected area. Do not allow the part to thaw and then refreeze.
  
  ■ Hypothermia: This is a serious medical emergency. Hypothermia is caused by severe body heat loss due to prolonged cold exposure. Immersion in water can make hypothermia worse or come on more quickly because the water increases heat loss. Symptoms include lack of shivering and what has been described as “the Umbles”—stumbles, mumbles, fumbles and grumbles — all of which are signs of mental slowing and lack of coordination. Hypothermia can progress to unconsciousness, irregular breathing and heartbeat and, eventually, death.
  + First Aid: If you find a Soldier in the early stages of hypothermia, start warming the Soldier immediately. If his clothes are wet, remove them. Loosen any restrictive clothes. Wrap the victim in dry blankets or a sleeping bag. Another person can get into the sleeping bag as an additional heat source. Get medical help immediately.
  If the Soldier is unconscious, cold to the touch and appears to have no pulse or breathing, don’t assume the Soldier is dead! Normal body temperature is 98.6 F. When body temperature gets down to 90 F, it tries to save energy and heat by trying to “hibernate.” It also decreases blood flow to the Soldier’s arms and legs, and his pulse and breathing become shallow. A Soldier may appear dead and his heart rate and breathing so low that untrained personnel miss it. Medics have resuscitated people with body temperatures as low as 82 F. Get the Soldier to a medical facility as soon as possible!