Why breathing cold air can hurt

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Why do my lungs seem to burn when running in cold temperatures? This is a common question, especially among new runners or runners who move to cold places. The lung is an amazing organ, evolved to warm and humidify inhaled air to body temperature and humidity without damaging tissue. Think of a tree with two main branches splitting off from the trunk and then splitting into smaller and smaller branches until the tiny branches sprout leaves. Turn the tree upside down and shrink it to chest size and you have the lung with the trachea as the trunk and the alveoli (air sacks) as leaves.

The warming and humidification of the air occurs rapidly starting in the mouth and nose, reaching body temperature and 100 per cent humidity before the air gets too deep into the respiratory tree. As air moves deeper into the alveoli that lie in direct contact with the blood vessels, it exchanges oxygen for carbon dioxide. While inspired air is cooling the lung tissue, the expired air adds some heat back to the cooled tissues on the way out of the lung.

Cold air is very dry. The burning sensation you feel in cold air is probably due to the combination of heat and water exchange that is occurring early in the inspiration of cold, dry air. For most people, this sensation goes away after a few breaths. It is not known to cause harm in a healthy lung, but can trigger an attack of bronchospasm in someone with asthma. Many people worry that the lung tissue will freeze in cold air, but the extensive network of blood flow through the lung tissue seems to prevent that from happening.

As best we can tell, the lung will tolerate extremely cold temperatures without cold damage. Growing up in northern Minnesota, cold weather was common and that did not stop us from running around outdoors. There are many year-round runners in Minnesota and other northern tier states, not to mention Nordic skiers and ice skaters, who are out in very cold conditions. Mother Nature seems to have developed a hardy system that will withstand the cold elements.

If cold air bothers you during exercise, you can wear a scarf or face mask to help “pre-warm” the air. I use a balaclava to keep my face warmer in very cold conditions and avoid frostbite on my cheeks. There are many designs that have extra materials over the mouth and nose to pre-warm the air.

Bottom line: You can exercise in cold conditions without fear of damaging your lungs, and the burning sensation will pass.