Ratings of perceived exertion and neuroendocrine reactivity (plasma catecholamines) were measured in type A and type B student volunteers during a metabolically equivalent physical stressor (cycle ergometry). Analysis of variance demonstrated that type A underrated the perception of exertion as compared to type B. Therefore, this neuropsychobiological interaction could partly explain the relationship between type A and the tissue pathology in the development of accentuated coronary heart disease.