The National Weather Service is warning much of the country about the polar vortex, an arctic air mass that is pushing much of the eastern and central U.S. down to record cold temperatures.

During this wave, workers are at increased risk of cold stress. Increased wind speeds can cause the air temperature to feel even colder, further increasing the risk of cold stress of those working outdoors, such as:

When the body is unable to warm itself, cold-related stress may result in tissue damage and possibly death. Four factors contribute to cold stress: cold air temperatures, high velocity air movement, dampness of the air, and contact with cold water or surfaces.

How cold is too cold?

A cold environment forces the body to work harder to maintain its temperature. Cold air, water and snow all draw heat from the body. The most common problems faced in the cold are hypothermia, frostbite, and trench foot.

What preventive measures should I take?

Plan for work in cold weather. Wearing appropriate clothing and being aware of how your body is reacting to the cold are important to preventing cold stress. Avoiding alcohol, certain medications and smoking can also help minimize the risk.

Protective Clothing is the most important way to avoid cold stress. The type of fabric even makes a difference. Cotton loses its insulation value when it becomes wet. Wool, silk and most synthetics, on the other hand, retain their insulation even when wet. Here are some clothing recommendations for working in cold environments:

• Wear at least three layers of clothing. An inner layer of wool, silk or synthetic to wick moisture away from the body. A middle layer of wool or synthetic to provide insulation even when wet. An outer wind and rain protection layer that allows some ventilation to prevent overheating. Layering provides better insulation. Do not wear tight fitting clothing.

• Wear a hat or hood to help keep your whole body warmer. Hats reduce the amount of body heat that escapes from your head.
• Wear insulated boots or other footwear.
• Keep extra clothing (including underwear) handy in case you get wet and need to change.
• Do not underestimate the wetting effects of perspiration. Oftentimes wicking and venting of the body's sweat and heat are more important than protecting from rain or snow.

With proper planning and training, employers can keep their employees safe during winter work. For more life-saving tips and information, check out our winter weather resource page. Additional information on cold stress is available from the National Institute for Occupational Safety and Health, and those involved in mining operations should view this winter alert from the Mine Safety and Health Administration.

Mandy Edens is the director of technical support and emergency management in the Occupational Safety and Health Administration.