Acute Cardiopulmonary Responses to the Two-Minute Step Test in Adults with Cardiovascular Risk Factors

Background: Field-based functional fitness tests are widely used to assess exercise capacity, yet their acute physiological responses in clinical populations remain incompletely characterized. This study examined acute cardiopulmonary responses to a two-minute step test (2MST) in adults with cardiovascular risk factors. Methods: A total of 239 adults (155 women, 84 men) with cardiovascular risk factors completed the 2MST. Pulmonary function (FVC, FEV₁, PEF), oxyhemoglobin saturation (SpO₂), and heart rate were assessed before and immediately after the test. Analyses were performed overall and stratified by sex, age, and tertiles of step count. Results: Following the 2MST, small but significant increases in FVC and FEV₁ were observed across sex and age groups (p < 0.05). Improvements in PEF were most evident in younger men. Participants with lower baseline stepping performance showed greater increases in SpO₂, particularly women, with improvements of up to approximately 1.7 percentage points. Heart rate increased by approximately 25 beats per minute during exercise and did not differ significantly across performance tertiles after adjustment. Conclusions: The two-minute step test elicits measurable acute cardiopulmonary responses in adults with cardiovascular risk factors. Beyond its role as a functional fitness assessment, the 2MST provides a brief physiological stimulus associated with improved oxygenation, particularly in individuals with lower baseline functional capacity.