Bronchoconstriction is seen at rest in patients with chronic heart failure, and may contribute towards exercise limitation. To investigate the effect of bronchodilator agents on exercise capacity, 10 patients (mean age 60 years, range 39-72) in New York Heart Association class II and III heart failure, underwent symptom-limited maximal exercise testing after inhalation of nebulized salbutamol (5 mg), ipratropium bromide (500 micrograms) or placebo delivered on separate days in a randomized, double-blinded study. There was an increase in forced expiratory volume in one second from pre-treatment to after nebulizer, 2.28 +/- 0.20 to 2.38 +/- 0.19 l (P < 0.05) with salbutamol, and 2.27 +/- 0.21 to 2.37 +/- 0.21 l (P < 0.05) with ipratropium bromide. There was an increase in maximal oxygen consumption after salbutamol 17.9 +/- 1.3 ml.kg-1.min-1 (P < 0.05) and ipratropium bromide 17.0 +/- 1.4 ml.kg-1.min-1 (P < 0.05), compared with placebo 16.3 +/- 1.4 ml.kg-1.min +/- 1. Peak minute ventilation during exercise also increased after salbutamol 52.8 +/- 4.5 l.min-1 (P < 0.05), compared with placebo 46.1 +/- 3.1 l.min-1. The small but significant increase in exercise capacity in chronic heart failure following bronchodilator agents implies that a degree of bronchoconstriction is present in these patients and contributes to exercise limitation.