When you are short of breath, your breathing can become too fast, too shallow, or jerky. Because of this you may not get as much air into your lungs as possible. 'Controlled breathing' (sometimes called 'pursed lips breathing') will help you to get as much air as possible into your lungs. This may help to ease shortness of breath. It is one way to slow down your breathing and to make each breath as effective as possible.
This is a companion discussion topic for the original article at https://patient.info/signs-symptoms/breathlessness-and-breathing-difficulties-dyspnoea/controlled-breathing-pursed-lips-breathing