{"id":997603,"date":"2026-10-21T08:00:00","date_gmt":"2026-10-21T06:00:00","guid":{"rendered":"https:\/\/kienzler-klima.de\/?p=997603"},"modified":"2026-08-19T11:24:36","modified_gmt":"2026-08-19T09:24:36","slug":"effects-of-dry-indoor-air-on-respiratory-tract-in-winter","status":"publish","type":"post","link":"https:\/\/kienzler-klima.de\/en\/effects-of-dry-indoor-air-on-respiratory-tract-in-winter\/","title":{"rendered":"What effect does dry indoor air have on the respiratory tract in winter?"},"content":{"rendered":"
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Dry indoor air puts a significant strain on the respiratory tract in winter: it dries out the mucous membranes in the nose, throat, and bronchi, weakens their natural protective function, and makes the body more susceptible to infections. The main cause is heated air, which in enclosed spaces often pushes relative humidity well below the health-recommended level. The following questions shed light on exactly what happens in the body, who is particularly affected, and what you can do about it.<\/p>\n

How does heated air in winter change indoor humidity levels?<\/h2>\n

Heated air significantly lowers relative indoor humidity because warm air can absorb more water vapor than cold air. Cold outside air with a relative humidity of, say, 80% contains very little water in absolute terms. When this air is warmed to 20\u00b0C or more in a room, its relative humidity often drops to 20 to 30% \u2014 well below the healthy range.<\/p>\n

This physical effect occurs in every heated building, regardless of whether radiators, underfloor heating, or air conditioning systems are used. It is particularly pronounced in poorly insulated buildings with high air exchange rates, as well as in offices and production halls where many people work in a confined space. There, indoor humidity in winter quickly drops to a level that places permanent stress on the mucous membranes.<\/p>\n

What happens in the respiratory tract when the air is too dry?<\/h2>\n

When indoor humidity drops too low, the mucous membranes in the nose, throat, and upper airways dry out. These mucous membranes are the body’s first line of defense: they filter out dust, pollen, and pathogens and remove them through the so-called mucociliary clearance mechanism. When there is insufficient moisture, this mechanism is disrupted.<\/p>\n

Short-term symptoms of dry air<\/h3>\n

Typical symptoms of dry air<\/strong> include a scratchy or burning sensation in the nose and throat, an irritating cough, dry lips, and irritated eyes. Many people report frequent throat-clearing or a persistently blocked feeling in the nose during winter, even without a cold. These complaints arise directly from insufficient moisturization of the mucous membranes.<\/p>\n

Long-term effects on the respiratory tract<\/h3>\n

Chronically dry respiratory mucous membranes significantly increase susceptibility to bacterial and viral infections. Viruses such as influenza or rhinoviruses survive longer in dry air and spread more easily, while the body’s own defenses are weakened. Those wondering why cold and flu waves so reliably occur in winter will find part of the answer in dry indoor air.<\/p>\n

Who is particularly susceptible to the effects of dry indoor air?<\/h2>\n

Certain groups of people react considerably more sensitively to dry air in winter than others. Children, the elderly, and people with chronic respiratory conditions such as asthma or COPD are most severely affected, as their respiratory mucous membranes are either not yet fully developed or already damaged.<\/p>\n

In addition, employees in offices, production halls, laboratories, and hospitals are particularly exposed because they spend many hours each day in air-conditioned or heavily heated spaces. Contact lens wearers and people with sensitive eyes also often notice the effects of dry indoor air first in their eyes, before the respiratory tract reacts.<\/p>\n

What indoor humidity level is recommended for good health?<\/h2>\n

The optimal indoor humidity level is between 40 and 60 percent relative humidity<\/strong>. Within this range, the mucous membranes of the respiratory tract function effectively, viruses and bacteria survive for shorter periods in the air, and general well-being is significantly better than at lower levels.<\/p>\n

Below 40% relative humidity, the mucous membranes begin to dry out. Above 60%, on the other hand, the risk of mold growth and dust mite proliferation increases. The goal for a respiratory-friendly environment with healthy humidity<\/strong> is therefore a stable average value that fluctuates as little as possible. Regular monitoring with a hygrometer is especially worthwhile in bedrooms and offices, where people spend many hours.<\/p>\n

How can dry indoor air in winter be effectively counteracted?<\/h2>\n

There are several effective measures against dry air in winter that can be usefully combined. The key is to address both the cause and to relieve the immediate discomfort.<\/p>\n