respiratory quotient


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quotient

 [kwo´shent]
a number obtained by division.
achievement quotient the achievement age divided by the mental age, indicating progress in learning.
caloric quotient the heat evolved (in calories) divided by the oxygen consumed (in milligrams) in a metabolic process.
intelligence quotient IQ; a numerical expression of intellectual capacity obtained by multiplying the mental age of the subject, ascertained by testing, by 100 and dividing by the chronological age.
respiratory quotient RQ; the ratio of the volume of carbon dioxide given off by the body tissues to the volume of oxygen absorbed by them; usually equal to the corresponding volumes given off and taken up by the lungs. It varies with the fuel source used: for carbohydrates it is 1.0; for lipids 0.7; for proteins 0.8; and with overfeeding (lipogenesis) 1.0–1.3.

res·pi·ra·to·ry quo·tient (R.Q., RQ),

the steady-state ratio of carbon dioxide produced by tissue metabolism to oxygen consumed in the same metabolism; for the whole body, normally about 0.82 under basal conditions; in the steady state, the respiratory quotient is equal to the respiratory exchange ratio.

respiratory quotient

n. Abbr. RQ
The ratio of the volume of carbon dioxide released to the volume of oxygen consumed by a body tissue or an organism in a given period.

res·pi·ra·to·ry quo·tient

(RQ) (res'pir-ă-tōr-ē kwō'shĕnt)
The ratio of the carbon dioxide produced during tissue metabolism to the oxygen consumed; reflects net substrate oxidation; can be determined by indirect calorimetry.

respiratory quotient (RQ)

the ratio of the volume of CO2 produced to the volume of O2 taken up in a given period of time. From RQ estimates it is possible to deduce what type of food is being oxidized. Carbohydrates have an RQ of 1.0, fats of 0.7 and proteins 0.9. An RQ lower than 0.7 indicates that organic acids such as malic acid are being oxidized (see CRASSULACEAN ACID METABOLISM): an RQ greater than 1.0 indicates that ANAEROBIC RESPIRATION is occurring.
References in periodicals archive ?
Respiratory quotient (qC[O.sub.2]).--The respiratory quotient was also affected by each of the factors studied.
Earthworm activity also altered the respiratory quotient in L/F and H material significantly.
The finding that EETA restored oxygen consumption and respiratory quotient to levels found in lean mice is supported by the beneficial increase in PGC-1[alpha], SIRT1, pAMPK, and COX-IV (a unit of themitochondrial OXPHOS complex) in theadipose tissueof mice fed a HF diet and treated with EET-A, thus highlighting the role of EETs in mitochondrial energy production and expenditure.
Body weights, fasting blood glucose, blood pressure, oxygen consumption, and respiratory quotient of mice fed regular chow or HF diet for 8 weeks.
As all measurements discussed will be made at steady state, I will refer to the ratio of VCO2/VO2 as respiratory quotient or RQ.
The molar ratio on a volume basis of the C[O.sub.2] evolved to oxygen consumed is termed the respiratory quotient (RQ).
It is unlikely that the respiratory quotient will vary much from 1; hence, this value of RQ is used in calculation of the average rate of pyrite oxidation.
Kawada, et al., "Capsaicin Induced Beta-Adrenergic Action on Energy Metabolism in Rats: Influence of Capsaicin on Oxygen Consumption, the Respiratory Quotient and Substrate Utilization," Proc.
A study in endurance athletes has shown that L-carnitine supplementation decreases their respiratory quotient (RQ) during a 45-minute cycling exercise--indicating a glycogen sparing effect that is thought to lead to improved performance and delayed fatigue onset.
The calculations assume 100% humidity at sea level and a respiratory quotient of 0.8, using the alveolar gas equation to determine PAO2: PAO2 = (FiO2 * (760 - 47)) - (PaCO2 / 0.8) A-a gradient = PAO2 - PaO2 http://www-users.med.cornell.edu/~spon/picu/calc/medcalc.htm
Both an increase in maximal oxygen consumption and a lowering of the respiratory quotient indicate that L-carnitine has the potential to stimulate lipid metabolism.
In endurance-trained athletes, L-carnitine supplementation (2 g/ day for 28 days) led to a significant reduction in Respiratory Quotient (RQ) during a 45 minute cycling exercise (compared with a placebo).

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