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not just the number.
VO₂/Work Rate (VO₂/WR) Slope: Explanation and Clinical Context The VO₂/WR slope quantifies the relationship between oxygen uptake (VO₂, in mL/min) and external work rate (WR, in Watts) during incremental exercise, typically measured during a cardiopulmonary exercise test (CPET). It reflects the efficiency of the cardiovascular and muscular systems in converting oxygen consumption into mechanical work. Normal VO₂/WR slope values generally range from 8–12 mL/min/W in healthy adults.
A slope below this range indicates impaired cardiovascular efficiency, often seen in heart failure, pulmonary vascular disease, or deconditioning. Conversely, unusually high slopes may reflect measurement artifact or unusually high aerobic efficiency. This parameter is particularly valuable in evaluating functional capacity, prognosis, and risk stratification in patients with chronic heart failure or other cardiopulmonary disorders.
Evidence & references1 primary source mapped
- Source 1
Hansen JE, Sue DY, Wasserman K. "Predicted values for clinical exercise testing." Am Rev Respir Dis. 1988;137:705-712. Wasserman K, Hansen JE, Sue DY, et al. "Principles of Exercise Testing and Interpretation." 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2011.
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