Breathlessness and Exercise in Patients with Cardiorespiratory Disease1–3

Previous studies have led to the revival of the hypothesis that breathlessness is the perception of respiratory muscle effort and is present when the tension developed by muscles increases, when the muscles are weak, or when both conditions are present simultaneously. Using a category scale, the intensity of breathlessness was measured in 20 subjects (2 normal subjects and 18 patients) undergoing an incremental exercise test (50 to 100 kpm/min) …