It is possible for a sick person to suffer from shortness of breath, and therefore it is important to discern when it is appropriate and when it is not. 

However, it is normal for an individual to experience shortness of breath after a strenuous exercise like running or walking up a flight of stairs.

It is abnormal to experience shortness of breath after routine walking, walking a few steps, or while at rest. Thus, when dyspnea is inappropriate to the activity, it is considered a symptom of an illness that might be linked to heart disease or asthma.

Shortness of breath or dyspnea should be of particular concern if it begins suddenly. Patients who develop abrupt onset of dyspnea often have problems with the heart whereas chronic shortness of breath is more likely due to coronary artery disease or valvular heart disease. 

 Chronic lung disease or emphysema is another medical condition that present with chronic shortness of breath.

In certain circumstances, shortness of breath might not be easy to recognise, especially when presents as a subjective symptom. 

Some individuals can experience inappropriate shortness of breath unknowingly and sometimes tend to deny when asked by doctor or when doctor is trying to take history from them. There are also patients who might appear to breath normally yet they have problem with shortness of breath.

There are three basic types of dyspnea that are generally investigated when a doctor is making diagnosis; cardiac, pulmonary, and functional (psychological).

Cardiac dyspnea generally occurs when the heart’s pumping action has become weakened or something obstructs the free flow of blood through the heart into the blood vessels. 

Poor pumping quality can be due to weakened heart muscle caused by coronary artery disease. Narrowing of a valve between the heart’s pumping chambers can also prevent blood from flowing from chamber to chamber.

What happens is that when too little blood is pumped forward with each beat, there is always a buildup of pressure in the lungs. This diminished pumping quality creates shortness of breath because blood and fluids begin to back up.

Pressure increases in the heart and ultimately in the lungs via the pulmonary veins. This added pressure in the pulmonary veins results in a leaking of fluid from the bloodstream into the air sacs in the lungs.

As the amount of fluid increases in the air sacs, breathing becomes more difficult. In addition, fluid may also back up into the lower legs, causing swelling of legs or edema.

With or without fluid accumulation in the air sacs, the buildup of pressure in the pulmonary veins also can cause the lung tissue to lose its suppleness and create the sensation of laboured breathing.

Pulmonary dyspnea is usually as a result of lung disease due to the narrowing or stiffening of the airways that makes it physically difficult to get air in and out of the lungs. 

People with asthma or emphysema often experience pulmonary dyspnea; this may occur when engaged in movements that prevent lungs from proper expansion. 

To distinguish cardiac dyspnea and pulmonary dyspnea is not always simple. People with pulmonary dyspnea, whose lungs have lost suppleness over a long period of time, tend to breathe more slowly and deeply when moving air out of the lungs, whereas those with cardiac dyspnea tend to move air in and out of the lungs in short, shallow breaths.

Then there is psychological kind of dyspnea, usually caused by anxiety. In this case, breathing tends to be shallow and rapid, causing hyperventilation.

This type of dyspnea may be even more dramatic than dyspnea caused by heart disease. It can usually disappear with exercise. Patients with psychological dyspnea usually complain of difficulty sensation when they breathe in air. 

Although this is a psychological rather than cardiac problem, it’s never ignored by medics. If psychological dyspnea is caused by panic disorder, can be successfully treated by anti-anxiety drugs or other psychotherapy means.

Other major causes of shortness of breath include pneumothorax, pulmonary embolism, and paroxysmal nocturnal dyspnea. Pneumothorax or a collapsed lung is usually a complication caused by air escape through a leak in one of the air sacs of the lung to build up in the chest cavity. 

Due to various causes of shortness breath, this symptom can manifest or present in a different manner to mimic the underlying illness. 

Dr Joseph Kamugisha is a resident oncologist in Jerusalem, Israel