respiratory quotient: meaning, definition, pronunciation and examples
LowTechnical/Scientific
Quick answer
What does “respiratory quotient” mean?
The ratio of the volume of carbon dioxide produced to the volume of oxygen consumed in a given period of respiration.
Audio
Pronunciation
Definition
Meaning and Definition
The ratio of the volume of carbon dioxide produced to the volume of oxygen consumed in a given period of respiration.
In metabolism and physiology, a dimensionless number used to indicate the type of fuel (carbohydrate, fat, protein) being oxidized by an organism or tissue, calculated from gas exchange measurements.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or spelling differences. The term is identical in both varieties.
Connotations
Purely technical with no regional connotative differences.
Frequency
Used with equal but low frequency in scientific contexts in both regions.
Grammar
How to Use “respiratory quotient” in a Sentence
The respiratory quotient of XX has a respiratory quotient of YA respiratory quotient greater than 1.0 indicates ZVocabulary
Collocations
Examples
Examples of “respiratory quotient” in a Sentence
verb
British English
- Researchers will quotient the respiratory gases.
- The system quotiented the metabolic outputs.
American English
- The software quotiented the respiratory data.
- We need to quotient the gas volumes.
adverb
British English
- The gases were measured respiratory-quotient-ly.
- The metabolism shifted respiratory-quotient-high.
American English
- The patient breathed respiratory-quotient-stably.
- The value changed respiratory-quotient-slowly.
adjective
British English
- The respiratory-quotient measurement was crucial.
- We analysed the respiratory-quotient data.
American English
- The respiratory-quotient analysis is complete.
- Check the respiratory-quotient value.
Usage
Meaning in Context
Business
Virtually never used.
Academic
Used in advanced biology, physiology, biochemistry, and exercise science lectures and papers.
Everyday
Not used in everyday conversation.
Technical
Core term in metabolic research, clinical physiology, and nutritional science for assessing substrate utilisation.
Vocabulary
Synonyms of “respiratory quotient”
Neutral
Watch out
Common Mistakes When Using “respiratory quotient”
- Mispronouncing 'respiratory' with stress on 'spire'. Correct stress: RES-pir-a-tory. Confusing it with 'respiratory rate' (breaths per minute).
FAQ
Frequently Asked Questions
In strict terms, RQ refers to cellular respiration, while RER is the measured exchange of gases at the mouth. They are often used interchangeably, especially when metabolic steady state is assumed.
Yes, an RQ > 1.0 can occur during hyperventilation, acidosis, or when converting carbohydrate to fat (lipogenesis), as more CO2 is produced relative to O2 consumed.
It is used in research and clinical settings to assess metabolic health, nutritional status, substrate utilisation during exercise, and in designing personalised diets.
Yes, it requires a device called a metabolic cart or indirect calorimeter to precisely measure the volumes of oxygen consumed and carbon dioxide produced.
The ratio of the volume of carbon dioxide produced to the volume of oxygen consumed in a given period of respiration.
Respiratory quotient is usually technical/scientific in register.
Respiratory quotient: in British English it is pronounced /ˈrɛspɪrət(ə)ri ˈkwəʊʃənt/, and in American English it is pronounced /ˈrɛspərəˌtɔri ˈkwoʊʃənt/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think: **Quotient** = a ratio. **Respiratory Quotient** = the ratio of breath-out (CO2) to breath-in (O2). Remember it by '**RQ** = Ratio of exhalation to inhalation **Quotient**.'
Conceptual Metaphor
A metabolic fuel gauge.
Practice
Quiz
What does a respiratory quotient (RQ) of 0.7 most likely indicate?