[Health in the 100-Year Life Era] In Winter, We Must Raise Our Body's 'Core Temperature'

Professor Park Chaeryeong, Department of Emergency Medicine, Severance Hospital. [Photo by Severance Hospital]

We are currently in the middle of winter. Recently, a cold wave with temperatures below minus 10 degrees Celsius has continued for several days. Among the specialties of emergency medicine is 'environmental injury,' which includes cold injuries and hypothermia during winter. Not long ago, a patient who suffered frostbite while walking on a snowy road visited the emergency room where I work, and frostbite cases frequently occur in winter.

The degree of skin and tissue damage in frostbite patients is determined by the exposure temperature, exposure time, and the rate of skin cooling. Tissue damage occurs not only when the skin freezes but also during the thawing process. The depth of injury is classified into first, second, third, and fourth-degree frostbite depending on whether the damage is limited to the skin layers or extends to deeper structures such as muscles or bones. The most common symptom is sensory impairment. First-degree frostbite, which is relatively mild, causes the skin to swell and become pale, while second-degree frostbite is accompanied by blisters but generally has a good prognosis. In cases of third- and fourth-degree frostbite, the skin turns black, structural damage and necrosis occur, and the prognosis is poor.

If frostbite is clinically suspected, one should immediately go to the nearest emergency room. At this time, to prevent further damage, heat should not be applied directly to the frostbitten area, nor should thawing be attempted. Before arriving at the hospital, the frostbitten area should not be rubbed or massaged, and ointments should not be applied. Wet and tight clothing should be avoided, and dry clothes should be worn to prevent secondary cold injuries. The affected arms or legs should be immobilized and elevated before going to the nearest emergency room.

Different people may feel cold in different body parts for various reasons. First, the distribution of blood vessels varies among individuals, leading to differences in blood flow and circulation. Blood is the main medium that transfers heat throughout the body. Generally, many people feel their hands and feet are colder than other parts because they are farther from the body surface and receive less blood flow. If there is an abnormality in blood circulation or if blood is not sufficiently supplied to a specific area, that area may become more sensitive to cold. Second, the distribution of fat varies. Body fat helps retain heat, so areas with more fat lose less heat and feel less cold. Lastly, sensitivity to temperature changes varies depending on the body part; areas such as the face, hands, and feet are more sensitive and may feel colder.

Besides frostbite, what are some good daily practices to manage body temperature during winter? Medically, hypothermia is defined by core body temperature (the internal temperature of the body's central part), not surface temperature. For patients with intubation, measuring temperature in the esophagus is known to best reflect heart temperature, and although less accurate, core temperature can also be measured in the bladder or rectum. To maintain body temperature, the core temperature must be raised, which requires keeping the torso warm.

Changing into dry and warm clothes and covering the entire body with warm blankets or comforters helps reduce heat loss. Using a heater to restore body heat is also important. To raise core temperature, wearing thermal underwear or attaching hot packs over thermal underwear during outdoor activities helps keep the body warm. Since the hands and ears are far from the body's core and prone to cold injuries, it is advisable to keep them warm with hats, scarves, and gloves. Consuming hot beverages such as tea, coffee, or hot chocolate helps maintain body temperature internally.