what is Pulmonary Hypertension?

Classifying PH

Pulmonary hypertension (PH) is classified according to how severe it is. This helps medical staff to understand how much PH is affecting someone. It also helps medical staff find the right treatment for people with PH.

The system that is used to classify PH was developed by the World Health Organization (WHO). It is based on how much exercise people with PH can do before they start to notice symptoms such as breathlessness.

WHO classification of PH

Class Description
No symptoms of any kind. Physical activity does not cause any symptoms
Comfortable at rest, but symptoms occur with ordinary physical activity
Comfortable at rest, but symptoms occur with less-than-ordinary effort (eg lifting the arms)
Symptoms while resting

Last medically reviewed: January, 2019 • Due for review: January, 2022