There are some dangers that are associated with exercising in the cold, even though it can be an exhilarating and rewarding experience. Cold injury is common in some of those extreme type sports, but not always necessarily in running, but it does have its dangers. Precautions do need to be taken and you do need to be aware of the signs of an impending problem with your body in the cold and you do need to know what to do.
Hypothermia is probably the greatest and most serious problem and most well known, due to the potential to become fatal if not addressed quickly and properly. You are at greater risk if it is cold, windy, and wet; if you are young, tall and thin; and if you run at a slower pace. The classic signs of hypothermia are shivering, slurred speech, a lethargy, a slow and shallow breathing, a weak pulse and a clumsiness or lack of coordination. If any of this starts to happen there is an urgency to getting the runner warmed up and get more help.
At the other extreme of the spectrum are the relatively minor issue of chilblains. This an inflammatory response of the small blood vessels in the toes (and sometimes the fingers) that can be quite painful. These do not happen in the extreme cold, but are more common in the colder climates, but are unheard of in the warm climates. They initially appear as a reddish colored painful and itchy patches on the toes, but can sometimes affect the fingers, nose and ears. If the chilblains do become chronic and keep occurring, they take on a dark blue color. They normally heal up reasonably quickly unless they keep recurring, which points to the importance of preventing them by use of warm socks and shoes. When one occurs, then soothing chilblain creams to stimulate the circulation is usually very helpful.
To avoid a cold injury, wearing several layers of clothing that designed for exercise are recommended. Take into account the direction of the wind when beginning your run and choose a route that is in a well populated area so you are not far from help if you need it. It is often a good idea to also wear a warm hat and gloves for further protection from the cold. If you have any real doubts, then don’t go for a run. You could have a rest day or use a treadmill that is indoors.