WHO Functional Class

The WHO Functional Class is a system used by doctors to describe how much a condition like pulmonary hypertension affects a person's daily activities. It ranges from Class I, where there are no symptoms during normal activity, to Class IV, where symptoms occur even at rest and limit all activity. This classification helps assess disease severity, guide treatment decisions, and predict outcomes. It’s a helpful way to understand how the condition impacts a person's ability to perform routine tasks and overall quality of life.