Validation of energy expenditure and macronutrient oxidation measured by two new whole‐room indirect calorimeters

Abstract

Objective The aim of this study was to validate two new whole‐room indirfect calorimeters according to Room Indirect Calorimetry Operating and Reporting Standards (RICORS 1.0). Methods For technical validation, 16 propane combustion tests were performed to determine accuracy and precision of energy expenditure (EE) and ventilation rates of oxygen (VO2), carbon dioxide (VCO2), and respiratory exchange ratio (VCO2/VO2). For biological validation, eight participants (mean [SD], age 24.1 [2.5] years; BMI 24.3 [3.1] kg/m2) underwent four 24‐hour protocols under highly standardized conditions: (1) isocaloric sedentary, (2) fasting sedentary, (3) isocaloric active, and (4) fasting active. Reliability (coefficients of variation [CV]) and minimal detectable changes (MDC) were calculated for 24‐hour EE, sleeping metabolic rate (SMR), physical activity energy expenditure (PAEE), thermic effect of food (TEF), and macronutrient oxidation rates. Results Technical validation showed high reliability and recovery rates for VO2 (0.75% and 100.8%, respectively), VCO2 (0.49% and 100.6%), and EE (0.54% and 98.2%). Biological validation revealed CV and MDC for active conditions of 1.4% and 4.3% for 24‐hour EE, 1.7% and 5.9% for SMR, and 30.2% and 38.4% for TEF, as well as 5.8% and 10.5% for PAEE, respectively. Mean CV and MDC for macronutrient oxidation rates were 9.9% and 22.9%, respectively. Conclusions The precision of 24‐hour EE and SMR was high, whereas it was lower for PAEE and poor for TEF.

Validity and reproducibility of a whole‐room indirect calorimeter for the estimation of VO2, VCO2, and resting metabolic rate

“…However, sensitivity analyses revealed no influence of protocol deviations on the measured parameters. An additional measurement day and measurements under different conditions (e.g., thermic effect of food) would also have been desirable to increase accuracy, precision and usability, and to be in line with previous validation studies (Allerton et al, 2021;Dörner et al, 2022;Schoffelen & Westerterp, 2008), but was not possible due to resource constraints.…”

“…In addition, RQ is a ratio with a physiological range of 0.7 to 1.2 and small deviations in VO 2 and VCO 2 can therefore produce substantial noise. Indeed, longer measurements tend to produce higher ICCs for 24‐h RQ (Allerton et al, 2021 ; Dörner et al, 2022 ) whereas basal, sleeping, and resting RQ appear less reliable (Allerton et al, 2021 ). We observed a significant inverse correlation between scaled VO 2 and scaled RQ residuals, indicating that as the variability in VO 2 increases, so does the variability in RQ, whereas this was not observed for VCO 2 .…”

“…Whole‐room indirect calorimeters (WRICs) provide accurate instruments for the measurement of respiratory exchange, energy expenditure, and macronutrient oxidation, and are currently in use at more than 40 research facilities globally (Chen, Smith, et al, 2020 ). Modern WRICs accurately capture components of total daily energy expenditure (TDEE) over a 24 h measurement period (Allerton et al, 2021 ; Dörner et al, 2022 ; Stinson et al, 2022 ). WRICs can be used to study energy requirements in humans with different metabolic conditions and to study the effects of different dietary exposures on the various components of energy expenditure (Hall et al, 2019 , 2021 ; Müller et al, 2021 ).…”

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Whole-room indirect calorimeters (WRICs) provide accurate instruments for the measurement of respiratory exchange, energy expenditure, and macronutrient oxidation, and are currently in use at more than 40 research facilities globally (Chen, Smith, et al, 2020). Modern WRICs accurately capture components of total daily energy expenditure (TDEE) over a 24 h measurement period (Allerton et al, 2021;Dörner et al, 2022;Stinson et al, 2022).

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How can we assess “thrifty” and “spendthrift” phenotypes?

“…Although all components of daily EE can be quantified from 24hEE data, their measurements have different degrees of accuracy. Specifically, sleeping EE is more accurate than DIT and PAEE measurement [7 ▪ ,8]. However, whole-room calorimeters have limitations such as high cost, limited availability, and the need for subjects to remain confined in the chamber for a prolonged period.…”