Exercise testing with gas exchange measurement is commonly used to evaluate patients with chronic heart failure (CHF). The most widely used prognostic measurement is peak oxygen uptake (VO2peak), with values ≤14 mL.kg-1.min-1 associated with increased mortality (1) and used as key criterion for cardiac transplant listing (2). A symptom-limited exercise test, however, may elicit a VO2peak lower than the maximum physiological limit (VO2max); the latter commonly confirmed using the secondary criterion of respiratory exchange ratio (RER) >1.05, despite RER being sensitive to test format (3). We, therefore, explored whether a ramp-incremental (RI) step-exercise (SE) (or RISE) test (4) could determine VO2max in CHF patients without the need for secondary criteria, by satisfying the criterion that two different work rates are terminated at the same VO2peak (5). Fourteen patients with stable CHF (NYHA class I: n=4, II: n=9, and III: n=1) performed a RISE95 test to the limit of tolerance in the format: RI (4-15 W.min-1; ~10 min); 5 min recovery (10W); SE (95% of peak RI work rate). Six patients also performed RISE95 tests using slow (RI 3-8 W.min-1; ~15 min) and fast (RI 10-25 W.min-1; ~6 min) incrementation rates. VO2 and RER were measured breath-by-breath by a mass spectrometer and turbine (MSX, NSpire, UK). Peak VO2 and RER values in RI and SE were compared within-subjects by unpaired t-test of the final 12 breaths of exercise. Where VO2max was confirmed, the individual 95% confidence interval of the estimate was established. As a group, VO2peak was lower (P<0.05) in RI than SE (mean±SD: 14.5±3.6 vs. 15.1±3.6 mL.kg-1.min-1). A within-subject comparison, however, revealed that the VO2max criterion was met in 9 of 14 patients (measurement sensitivity range 0.6-3.8 mL.kg-1.min-1), despite RER being greater in the other 5 (1.13±0.1 vs. 1.22±0.1; P=0.06). Group VO2peak was not affected (P>0.05) by ramp rate, but a fast ramp reduced the incidence of VO2max confirmation (1 of 5 patients) compared to slow (4 of 6 patients). RER was greater (P<0.05) in the fast ramp (1.22±0.1) compared to slow (1.11±0.04). The single-visit RISE95 test incorporating incremental- and step- exercise phases, each to the volitional limit, was well tolerated by CHF patients: In only 1 of 26 tests did a patient elect not to perform the SE phase. The test was sufficiently sensitive to discriminate VO2max in 9 of 14 patients to within ~10% (or 1.7mL.kg-1.min-1) without the need for secondary criteria, and eliminated the incidence of false-positive. The end-exercise RER was sensitive to the relative ramp-incrementation rate and its use as a secondary criterion for VO2max provided a false-positive in every incidence. Therefore, the RISE95 protocol and novel confidence-interval criterion can provide robust VO2max measurement in CHF patients without the need for secondary criteria.