Why does asthma cause shortness of breath


What happens in the bronchi of an asthmatic?

In asthma sufferers, there is a constant readiness for inflammation and defense in the lower respiratory tract (bronchi and bronchioles), which is intensified by certain influences (triggers). Due to the frequent inflammation, the bronchial tubes of an asthmatic sufferer are overly sensitive and react to harmless stimuli with a violent defense reaction: They constrict like spasms, the mucous membranes in the bronchial walls swell and often form an excessive amount of tough mucus. This leads to whistling and humming breathing noises, dry coughing with thick, glassy phlegm that is difficult to cough up, tightness in the chest and shortness of breath.

As a result, the diameter of the bronchi becomes narrower and the air you breathe can no longer flow in and out unhindered (obstruction). This overworks the respiratory muscles, which is the main cause of shortness of breath. In addition, it is difficult for asthmatics to breathe out. After each breath, a little more air remains in the lungs than normal until a new equilibrium is reached. As a result, the lungs expand a little more with each breath (acute emphysema). This also makes it more difficult to inhale further: the less the used air, which should actually be exhaled again, can flow out of the lungs, the less space remains in the lungs to inhale fresh air. Although the lungs are inflated with air, this additional proportion of air cannot be breathed, so to speak. This increases the shortage of breath.

You can really feel how an asthmatic must feel during an asthma attack by trying to breathe through a straw for a few minutes. While it is still possible to breathe in through the straw, it is almost impossible to breathe out quickly enough through a straw. After a short time you will stop because of shortness of breath.

With the overall prolonged exhalation, there is more friction due to the narrowing of the lower airways and thus an amplification of the flow noises: whistling (the doctor calls this wheezing) and humming can be heard clearly.

The constant readiness of the airways to inflame and defend themselves does not make asthmatics consistently uncomfortable. At times they are only slightly affected or not at all. Only contact with a trigger causes and intensifies the asthmatic symptoms and can also provoke an asthma attack. In asthma, two things must come together: a constant readiness for inflammation and an external influence (trigger) that intensifies (triggers) the existing inflammation and thus causes the symptoms typical of asthma.