Dyspnea is the medical term used to describe sensation of breathlessness, inadequate or difficult breathing. Being short of breath is something most of us have experienced after intense physical exertion, but when this sensation is disproportionate to levels of physical activity, it is generally a symptom of another medical condition.
There are a number of medical conditions that can cause dyspnea, some of which are extremely serious and so it is important that this symptom is not ignored. Any unexpected or severe shortness of breath should be treated as a medical emergency.
The sensation of dyspnea differs between individuals as does the perception of what it means to be short of breath. For some people, merely walking up a flight of stairs can leave them with an uncomfortable sensation of shortness of breath, where others may only be concerned when they feel they are struggling to breathe. In some instances mild shortness of breath is normal, for instance if one has a cold with extreme nasal congestion, or after exercise when very unfit.