Cold Weather Injuries Peak in January, February

Courtesy Photo | Service members are often in danger of experiencing cold weather-related injuries because of the cold and wet conditions present during various training and operational activities. CWI risk can be reduced if both unit leaders and service members are aware of the conditions and symptoms and how to prevent them. (Defense Health Agency-Public Health graphic illustration by Joyce Kopatch).  

UNITED STATES

01.13.2025

Courtesy Story

Defense Health Agency

By V. Hauschild, MPH, Defense Health Agency-Public Health Public Affairs
Service members are often in danger of experiencing cold weather-related injuries because of cold and wet conditions present during various training and operational activities.

Wind chill and wetness (including from sweat) can increase the rate of heat loss. Cold weather-related injuries, otherwise known as CWIs, can occur at warmer conditions as high as 60 degrees Fahrenheit, but CWIs are much more common at freezing temperatures below 32 F.

“January and February are consistently peak months for our service members to experience CWIs,” says Dr. Chip McCannon, a preventive medicine physician working for the Defense Health Agency–Public Health in Aberdeen, Maryland.

McCannon says that while CWIs do occur throughout the year, service members and unit leaders should be on the alert when temperatures drop.

Be On High Alert Now, But Be Aware All Year

When a service member experiences a CWI, the incident must be reported for military health surveillance to monitor trends and identify occurrence of cases outside expected patterns.

Katherine Kotas, a DHA-PH epidemiologist who analyzes the surveillance data, confirms that CWI cases for military service members are reported most frequently in the winter months.

“Military CWIs are reported year round, but the primary months of concern are from October through March,” says Kotas. “In the 2024 cold season, nearly half of the CWIs were reported between January and February.”

Kotas says that surveillance data from 2018 to 2023, as reported in the November 2023 Medical Surveillance Monthly Report, showed service members who most frequently experienced CWI were enlisted males younger than age 20 in combat-specific occupations, especially in the U.S. Marine Corps and U.S. Army.

What are Cold Weather Injury Conditions and Symptoms?

McCannon describes three categories of CWI monitored by the military:

1. Non-freezing cold injuries occur primarily to hands and feet exposed to cool wet conditions. The two primary conditions include:

• Chilblains, from one to five hours of continuous or repeated skin exposure to cool wet conditions under 50 degrees such as in wet areas, wet weather, or from sweat in boots or gloves. Skin initially appears wet, white, and shriveled but becomes cold, swollen, and waxy. A casualty may feel pins and needles, tingling, numbness and then pain. Skin may develop blisters, open weeping, or bleeding.

• Immersion foot, also known as trench foot, is typically associated with prolonged (>12 hours) exposure of tissue, especially the feet, to wet cold and conditions at 32 degrees to 60 degrees. Inactivity and damp socks and boots (or tightly laced boots that impair circulation) can speed the time of onset and severity. Cold, numb feet may progress to feeling hot with aches, then shooting pains and pain sensitivity. Foot swelling and redness may change to pale and blue and may include bleeding.

2. Freezing cold injuries, or frostbite, is the freezing or crystallization of tissues primarily of the extremities (fingers, toes, ears, nose), when skin is exposed to extreme cold or high winds. Exposure time can be minutes or instantaneous if skin is exposed to extreme cold or high winds. Skin will feel cold, stiff, or woody and turn gray or a waxy-white color but can progress to purple or blackened skin. A casualty will feel numbness, tingling, or a stinging sensation. Blisters and restricted joint movement may also be present.

3. Hypothermia occurs when the body’s core temperature falls below 95 degrees. This can occur suddenly, such as during partial or total immersion in cold water, or over hours or days, such as during extended operations or survival situations. Hypothermia is usually characterized as mild, moderate, or severe, based on a casualty’s core temperature as measured rectally with a thermometer (oral and ear temperatures do not yield accurate results in a cold environment).

An initial sign of hypothermia is vigorous shivering, though shivering may decrease or even stop as a person’s core temperature continues to fall. A casualty may also show increasingly slowed reactions and changes in behavior, including mumbles and fumbles, as cold affects muscle and nerve function. This can progress to confusion, sleepiness, slurred speech, shallow breathing, weak pulse, and low blood pressure.

How Can You Reduce Your Risk of Cold-Weather Injuries?

McCannon says while CWIs will always be a threat during military training and combat operations, the risk can be reduced if both unit leaders and service members are aware of the conditions and symptoms and how to prevent them:

Remember the acronym COLD:
o Keep it Clean
o Avoid Overheating
o Wear it Loose and in Layers
o Keep it Dry

Everyone should keep their feet dry by changing wet or damp socks as soon as possible. McCannon recommends avoiding cotton clothing, socks, or gloves as cotton holds perspiration. He also emphasizes awareness of what can increase an individual person’s risk.

Personal Characteristics that Can Increase Your CWI Risk

Medical conditions. Having had a prior CWI increases one’s risk of another CWI, possibly a more severe one. Raynaud’s Disease causes blood vessel constriction in cold temperatures, resulting in reduced blood flow to fingers and toes which increases frostbite risk. Other diseases that may also increase susceptibility to CWIs include anemia, diabetes, sickle cell disease, hypotension, hypothyroidism, and atherosclerosis.

Some medications. Benzodiazepines, tricyclic antidepressants, barbiturates, and general anesthetics impair blood vessel constriction, increasing risk of CWI.

Alcohol. Though it imparts a sense of warmth, alcohol dilates skin blood vessels which increases heat loss. It can also impair the senses and judgment, making it difficult to notice signs and symptoms of a CWI.

Nicotine. Smoking, chewing, and vaping can cause increased constriction of skin blood vessels, which increases the risk for frostbite.

Self-care tips to reduce your risk of developing a cold weather injury:
• Dress in loose clothing and layers. This helps you regulate your body’s temperature and remove or change layers.

• Keep skin dry by changing out of wet clothing, gloves and footwear (especially socks). Heat loss increases when skin is damp, increasing risk of CWI.

• Alert your unit leader and battle buddy of prior CWI, medical conditions, or medications that may increase your risk of CWI. Heightened awareness balances the increased risk.

• Abstain from unhealthy behaviors such as alcohol or nicotine use on days preceding and during activities in cold or wet conditions.

• Consume adequate calories through nutritious food. More calories are needed to maintain critical body thermal functions such as shivering in colder temperatures.

• Drink plenty of fluids to stay hydrated. The temperature of the fluids is not as important as maintaining hydration; in cooler temperatures you may not realize how much fluid you are losing through sweat.

• Maintain fitness levels. Keeping a healthy weight and doing 150–300 minutes of aerobic exercise and two sessions of strength work each week can increases your body’s resilience to illness and injury.

• Get quality sleep each day. Getting sleep allows your body to recharge so it can function more efficiently. If military operations don’t allow for the ideal six–eight consecutive hours, utilize military guidance for tactical naps.

• Avoid face camouflage. Face camouflage paint should not be used when the air temperature falls below 32 degrees because the paint conceals changes in skin color which signal the early development of frostbite.

What Happens if You Are Injured?

“To avoid further tissue damage, use dry, loose layers of clothing for warmth and seek medical assistance, says McCannon. “Do not attempt to rub injured skin, and do not use snow or external heat sources, including warm water or snow. Do not attempt to thaw frozen tissues if there is a chance of refreezing before getting medical attention.”

Additional information sources:
• DHA Factsheet – Cold Weather injuries: https://ph.health.mil/PHC Resource Library/disease_epi-cold-weather-Injuries-factsheet.pdf

• Uniformed Services University-Consortium for Health and Military Performance (CHAMP), Human Performance Resources- Extreme Weather: https://www.hprc-online.org/physical-fitness/environmental-extremes/how-prevent-cold-injuries

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• Date Taken: 01.13.2025
• Date Posted: 01.13.2025 14:19
• Story ID: 488981
• Location: US