Respiratory exchange ratio
Abstract
Abstract Key Points: • The respiratory exchange ratio (RER) is the ratio of VCO2 to VO2. • Beyond the anaerobic threshold (AT), the RER increases above 1.0 as VCO2 rises more steeply than VO2, reflecting the production of CO2 from the buffering of lactic acid. • At peak exercise, an RER >1.1 is an indicator of good effort by the subject (provided they are not limited by lung disease). • RER increases further during the recovery phase of a CPET. • Subjects with dysfunctional breathing can have erratic RER traces, especially at rest and in early exercise.
Fields of Study & Subjects
Cardiovascular and exercise physiology
Sports Performance and Training
Biomedical and Chemical Research
Publication details
- Journal / source
- Oxford University Press eBooks
- Pages
- 81–85
- Publication date
- 1 February 2026
- Language
- EN
- Document type
- Book chapter