Objective: To validate a tool for assessment and control of functional capacity and peak oxygen uptake. Methods: A transversal, correlational study was conducted in which 111 subjects (49.81 ± 11.16 years) were evaluated, their body mass index (BMI) was 31.42 ± 4.07, classified with moderate and high cardiovascular risk, according to the American Association of Cardiovascular and Pulmonary Rehabilitation. Its peak oxygen uptake was measured directly and also through the Step Test 3x1 (ST3x1). Results: Peak oxygen uptake in ST3x1 corresponded to 28.54 ml•kg-1•min-1 and direct measurement at 28.14 ml•kg-1•min-1, with a “strong positive” Pearson correlation r = 0.81, Student n/s p = 0.14 Conclusion: ST3x1 is a valid alternative to estimate peak oxygen uptake in the group studied, and can be used in mass public health physical activity programs
