This issue of Heart has a group of articles about hypertrophic cardiomyopathy with two of these studies addressing exercise capacity. In a study from The Heart Hospital in London (See page 644 and figure 1) cardiopulmonary exercise testing showed a reduced peak oxygen consumption and cardiac index in 70 patients with hypertrophic cardiomyopathy compared to normal volunteers. Left ventricular outflow tract obstruction was present in 31% of patients at rest and an additional 14% had obstruction provoked by exercise. Compared to patients without obstruction, outflow obstruction at all levels of exercise was associated with an inability to augment stroke volume index and a higher oxygen consumption figure 1.