Cold weather brings with it extra challenges for people with asthma and airway problems. With good preventive measures, appropriate medication and prevention of exposure to cold, asthmatics can still go out in the winter weather. Cold alone is often not the biggest problem. Particle contamination as a result of cold weather, particularly in towns and built-up areas, will often exacerbate symptoms of asthma. Frequent colds in the winter season will also be associated with worsening of symptoms. Asthma is a disease with a highly variable course, but most asthmatics will feel discomfort in cold weather. It is important to be careful during strenuous exercise in very cold weather (temperatures less than minus 10°C).
What happens?
The reason why many asthmatics suffer worsening of symptoms when breathing in cold air is due to hypersensitive airways and not a cold allergy. Inspiration of cold air leads indirectly to drying out of the airways and thereby bronchoconstriction. Breathing in through the nose is also more difficult in extremely cold weather. In asthmatics, mouth breathing leads to even more constriction of the airways, as the air is not pre-warmed prior to reaching the airways.
The nose plays a very important role in protecting the airways against untreated air, and it has been shown that the size of the nose has an impact on the ability to breathe through the nose. The Inuit live in an extremely cold climate (in Greenland) and studies have shown that they have higher nasal cavities than many other ethnic groups!
Cold and exercise
It is important to be aware that exercise in extreme cold can lead to worsening of asthma where appropriate protective measures are not taken. So-called exercise-induced asthma may be worsened indirectly by strenuous exercise in cold weather because of excess supply of cold air into the airways. Problems with exercise-induced asthma often occur as a result of strenuous exercise or competition at temperatures lower than minus 15oC.
Normal airways too can to some degree react to exertion in cold weather – both in animals and humans. Tissue samples from the respiratory passages of sled dogs which have taken part in Alaskan dog-sled races have shown various degrees of inflammatory reactions – exactly the same as in our cross-country skiers when competing in cold weather.
It is nonetheless important to remember that physical activity improves fitness and the ability to conquer asthma. Asthmatics are able to participate in regular activity, including in cold weather, providing they are well protected against cold air at the nose and mouth and with the appropriate amounts of preventive medicine. Exercise should be adapted to the individual. In general, asthmatics should not perform fitness training at temperatures of less than minus 5oC.
Cold-induced asthma is not the same as cold-allergy!
Cold allergy takes the form of urticaria (“nettle rash”) occurring on exposure, especially to cold water. Urticaria as a result of cold or cold water can lead to serious reactions such as swelling involving large areas of the body. Cold allergy can be one cause of allergic shock. Cold allergy is most commonly triggered by bathing in very cold water.
Cold and particle contamination
In towns and built-up areas, cold days with minimal wind and high traffic density will result in increased concentrations of gases and particles in the air. Nitrogen dioxide (NO2) from internal combustion engines (older cars) may contribute to increased air contamination. NO2 exposure, particularly in asthmatics, can result in reduced lung function. In Norway, exhaust fumes, in particular from diesel engines, contribute to increased atmospheric pollution. Together with road traffic, wood-fired central heating on cold days will also be a significant source of contaminated air, resulting in large quantities of suspended dust, the greatest emissions coming from old wood stoves. Suspended dust can both trigger and exacerbate the disease in people with chronic airways disease. Suspended dust may also act as a vector for allergens, which can trigger allergies.
Protection/Prevention
The Jonas cold weather mask from the Norwegian Asthma and Allergy Association (NAAF) provides good protection against cold and dry air and is well-suited to asthmatics who feel that their asthma worsens in cold weather. The Jonas mask also provides good protection when exercising in cold weather. A beanie, headover or scarf with a mesh ensures that the air is warmed up before it goes into the lungs, thereby reducing the problems encountered by asthmatics and others who have problems breathing cold air into the lungs through the nose. The cost of this may be subsidised by the National Insurance Service (Folketrygden), in instances where the cold weather mask is recommended by a specialist in internal or respiratory medicine. A brochure may be obtained on request from NAAF or by visiting our website.
Preventive medicines (bricanyl or ventolin), which widen the airways and thereby reduce the symptoms, are available for asthma symptoms brought on by cold weather. Where appropriate protection and the correct medication are used, asthmatics should not be overly anxious about exercising in temperatures as low as minus 15oC. However asthma is a highly individualised disease with significant variations in the disease course and some individuals will notice problems in breathing at only a few degrees below zero. It is important to have an understanding of your own illness and to be aware of your own reactions.
It is also important to remember that the elderly, the infirm and small children are more vulnerable to very cold air than others. Nor will small children be able to say, to the same degree, when they are having problems as a result of their asthma. Severe cold may also have other negative health consequences, e.g. frostbite. The skin will be especially exposed to cold weather combined with strong wind and moisture.