Cardiopulmonary Function Assessment Scores (CPET)

Oxygen Uptake Efficiency Slope (OUES) Calculator

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OUES Regression Calculator

Enter paired oxygen uptake and minute ventilation measurements from an incremental CPET.

0Data points

Enter one paired measurement per line as VO₂ (mL/min), VE (L/min). Use a comma, semicolon, or tab between values. Include at least 3 valid pairs; use the same exercise interval for all pairs.

Example data are illustrative only. Replace them with measurements from the patient's CPET report before calculating.

—OUES
Linear regression slope
Calculation complete

About OUES

The oxygen uptake efficiency slope (OUES) is a CPET-derived index describing the relationship between oxygen uptake and the logarithm of minute ventilation during incremental exercise. It can be estimated from submaximal exercise data, but interpretation depends on the population, protocol, units, and method used.

Calculation method

VO₂ = a × log₁₀(VE) + b
OUES = slope a

For the entered data, the calculator performs ordinary least-squares linear regression with VO₂ (mL/min) as the dependent variable and log₁₀[VE (L/min)] as the independent variable. The estimated slope is reported as OUES.

Important considerations

  • Use paired measurements from the same incremental CPET and a consistent sampling interval.
  • VE must be greater than zero; VO₂ and VE must be numeric, finite values in the units specified above.
  • OUES depends on the units and analysis protocol. Do not compare values derived using different units or data-selection methods without checking comparability.
  • There is no single universal adult normal range suitable for every age, sex, body size, and clinical population. Interpret against appropriate validated reference values and the clinical context.

References

Baba R, Nagashima M, Goto M, et al.Oxygen uptake efficiency slope: a new index of cardiorespiratory functional reserve derived from the relation between oxygen consumption and minute ventilation during incremental exercise. J Am Coll Cardiol. 1996;28(6):1567–1572. doi:10.1016/S0735-1097(96)00412-3.
Hollenberg M, Tager IB.Oxygen uptake efficiency slope: an index of exercise performance and cardiopulmonary reserve requiring only submaximal exercise. J Am Coll Cardiol. 2000;36(1):194–201. doi:10.1016/S0735-1097(00)00691-4.
Oxygen uptake efficiency slope in healthy normal weight young males: an applicable framework for calculation and interpretation.PeerJ. 2022. This open-access study describes OUES determination using linear regression of VO₂ against log-transformed VE. doi:10.7717/peerj.13709.
Clinical disclaimer: This calculator performs a mathematical regression on the data entered. It does not diagnose disease, provide a validated universal normal range, or replace review of the complete CPET, technical quality, protocol, and clinical context by a qualified clinician.
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