Table 3. New York Heart Association functional classification of dyspnea.

Class	Symptoms
I	No limitation of daily physical activity. Ordinary physical activity does not cause symptoms.
II	Slight limitation of daily physical activity. Comfortable at rest, but ordinary physical activity causes symptoms.
III	Marked limitation of daily physical activity. Comfortable at rest, but less than ordinary activity causes symptoms.
IV	Unable to perform any physical activity without discomfort. Symptoms of heart failure at rest. Discomfort increases with any physical activity.