Cold stress is an umbrella term that refers to cold-related illnesses that occur when the body can no longer maintain its normal temperature. These illnesses range from mild and treatable to permanent tissue damage and death.
Four factors contribute to cold stress:
Cold stress can happen even in moderate temperatures. For example, a temperature of 40° F with a 35 mph wind can make it feel like 28° F. (This is known as the wind chill factor). If it is raining, conditions become even more dangerous.
Many occupations are at risk for cold stress, including snow clean-up crews, sanitation workers, miners, police and emergency response personnel, and construction workers. Any employee who works in cold and wet conditions for a prolonged period could suffer from cold stress.
Certain pre-existing conditions, medications, and physical conditioning can exacerbate cold stress. Pre-existing conditions that can aggravate cold stress include hypertension, hypothyroidism, diabetes, asthma, and bronchitis. Medications that can increase cold stress include antidepressants, sedatives, tranquilizers, heart medication, and alcohol. Finally, people in poor physical condition or who are older might be higher risks for cold stress.
If people are exposed to cold, wind, dampness, and cold water for long periods of time, their body will use most of its stored energy to maintain its internal temperature. When the body can no longer sustain a normal temperature of 98.6° F, blood flow will shift from the extremities (e.g., hands, feet, arms, legs) to the core (e.g., chest and abdomen). When this happens, the conditions are right for several cold-related illnesses—most notably hypothermia and frostbite.
Hypothermia (which means “low heat”) occurs when body heat is lost faster than it can be replaced and body temperature drops below 95° F. Hypothermia starts with shivering but can quickly progress to slurred speech, lack of coordination, and memory loss. As symptoms become more severe, recovery becomes increasingly difficult.
Frostbite happens when layers of skin tissue freeze. Frostbite usually occurs in the extremities, such as the face, ears, fingers, and toes. Symptoms include tingling and stinging followed by numbness. The skin will turn from red to purple to white and will be cold and waxy. Touching cold metal will cause frostbite faster than exposure to cold temperatures alone. Once an area is affected by frostbite, it will always be susceptible.
When feet become wet or damp, trench foot (or immersion foot) can become a problem. Trench foot occurs when feet are in cold water for too long. Symptoms include tingling, itching, burning, and blistering.
Another illness related to cold stress is chilblains, which happens when the skin is repeatedly exposed to temperatures just above freezing and small blood vessels become inflamed. The most affected areas are cheeks, ears, fingers, and toes. Symptoms include itching, red patches, swelling, and blistering. Chilblains is usually not permanent but can lead to infection.
For detailed information on recognizing and treating the illnesses related to cold stress, check out this newsletter published by the Colorado School of Mines.
Fortunately, cold stress can be avoided by following proper safety precautions and dressing appropriately.
If you are interested in learning more about appropriate cold weather gear for your team, contact us today.