Respiratory quotient metabolic rate

Rest, respiratory quotient during, 287-288 Resting metabolic rate IRMR], 302 Resting metabolism, 193-194 Restriction enTymes, 947-919 Reticulocytes, 513 Retinal, 558 ll-cjs-Retinat, 561,562... 

Basal metabolism O2 consumption CO2 production Respiratory quotient Blood volume Resting cardiac output Systemic blood pressure Heart rate at rest General cardiac output... 

Whole room calorimetry is considered the gold standard for measuring energy expenditure in humans. Although the subject is free to move around in the calorimetric chamber, spontaneous physical activity is greatly reduced. Furthermore, the measurement is carried out under strictly controlled, artificial environmental conditions and often is of short duration (<24 hr). However, indirect calorimetry does provide important information about the basal metabolic rate, respiratory quotient, sedentary energy expenditure, and sleeping metabolic rate. 

Another goal of the USDA study was to determine whether CLA enhanced energy expenditure, lipolysis, or fat oxidation in humans, similar to the effects observed in animals. Accordingly, measurements of metabolic rate and respiratory quotient were made by indirect calorimetry, and stable isotope tracers of palmitate and glycerol were used to measure the rate of appearance of free fatty acids and glycerol as well as whole body lipolysis and apparent reesterification. CLA supplementation had no effect on metabolic rate or whole-body fat oxidation rate during rest or exercise. Similarly, CLA did not change lipolytic rate, fatty acid release from adipose tissue, or apparent FFA reesterification rates under conditions of rest or exercise (33). 

The most commonly made calorimetric tests are the measurements of the basal metabolic rate and the respiratory quotient. Details follow ... 

RESPIRATORY QUOTIENT (RQ). This measurement may be made as part of the determination of the basal metabolic rate, or it may be measured separately in order to provide other information, such as the amounts and types of the nutrients which are metabolized under various circumstances. The noted American physiologist Eugene DuBois made many determinations of the RQ for the latter purpose. 

The classical Warburg method of manometric indirect calorimetry (see e.g. [41 ]) determined the oxygen consumption rate by a reduction of volume and the carbon dioxide production by a volume increase in the gaseous environment of an organism under research. The ratio of carbon dioxide production and oxygen consumption, the so-called respiratory quotient RQ, rendered information about the substrate(s) used in this specific metabolism. Table 2 presents the RQ values for various pure or mixed substrates and the expected heat production or gas exchanges. 

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