The authors compared two types of spiroergometric tests in 14 patients with chronic heart failure (NYHA II-III, ejection fraction < 40%). Test A: 0.25 W/kg 3 minutes, 1 minute break, increase by 0.25 W/kg á 3 minutes. Test B: 25 W 2 minutes without break, increase by 10 W á 2 minutes. The two tests did not differ as to the achieved heart rate, blood pressure reading, oxygen consumption and biochemical parameters at the end of the load, even at the level of the anaerobic threshold. There was a significant statistical difference in the duration of the load: test A lasted 16.4 minutes, test B 9.7 minutes (p < 0.001). The length of the test B correlated with the peak oxygen consumption per 1 kg body weight (p < 0.001, r 0.9866). The authors recommend for common practice test B with a defined period of the load as sufficient.