Development of a standardized single‐session cardiopulmonary exercise test for combined assessment of peak oxygen uptake and on/off‐kinetics

Peak oxygen uptake ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>peak</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{peak}}}}$</mml:annotation></mml:semantics> </mml:math> ) and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}}}$</mml:annotation></mml:semantics> </mml:math> on/off-kinetics are key indicators of exercise capacity and health outcomes, but their assessment often requires separate laboratory visits, which limits feasibility. This cross-sectional study aimed to develop a single cardiopulmonary exercise test (CPET) for both assessments. We designed a single-session combined CPET protocol using an upright cycle ergometer in healthy volunteers (n = 20). <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>peak</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{peak}}}}$</mml:annotation></mml:semantics> </mml:math> was first estimated using an a priori formula. The constant work rate (CWR) part of the test (on-kinetics) was set to an intensity of 30% <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>reserve</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{reserve}}}}$</mml:annotation></mml:semantics> </mml:math> . After an incremental test to measure <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>peak</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{peak}}}}$</mml:annotation></mml:semantics> </mml:math> , a 10-min recovery period was used to evaluate off-kinetics. Twenty volunteers (9 females and 11 males), 28.0 ± 8.1 years completed the protocol. No significant differences were found between predicted and measured <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>peak</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{peak}}}}$</mml:annotation></mml:semantics> </mml:math> (P = 0.47). A strong correlation (r = 0.88) and good agreement (Bland-Altman bias = -0.82 mL kg^-1 min^-1) were found between the calculated/actual individuals' 30% <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>reserve</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{reserve}}}}$</mml:annotation></mml:semantics> </mml:math> (mL kg^-1 min^-1) and the measured steady-state <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}}}$</mml:annotation></mml:semantics> </mml:math> at CWR. The measured exercise intensity at CWR closely matched the target of 30%, with no statistical differences, with an average difference of 0.2 percentage points. Small-medium Cohen's d (0.16) indicated high similarity between predicted and measured <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>peak</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{peak}}}}$</mml:annotation></mml:semantics> </mml:math> . <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}}}$</mml:annotation></mml:semantics> </mml:math> on- and off-kinetics analyses were also performed for all participants with mono-exponential fittings. A single-session protocol for the combined assessment of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:mrow><mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:mi>peak</mml:mi></mml:mrow> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}{\mathrm{peak}}}}$</mml:annotation></mml:semantics> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> <mml:annotation>${{\dot{V}}_{{{{\mathrm{O}}}_2}}}$</mml:annotation></mml:semantics> </mml:math> on/off-kinetics was developed. This protocol will enable greater recruitment and participation in research and enhanced detail for clinical CPET use. Future research should evaluate intra- and inter-participant reproducibility over repeated sessions.