Background and aims: A personal indirect calorimeter allows everyone to assess resting and non-resting energy expenditure, thus enabling accurate determination of a person's total calorie need for weight management and fitness. The aim of this study is to compare the performance of a new personal metabolic rate tracker based on indirect calorimetry, Breezing ® , with the Douglas bag method, the gold standard method for energy expenditure (EE) measurement. Methods:Energy expenditures (EE) at rest and during activities, and respiratory quotient (RQ) were measured for 12 healthy subjects, including 7 male and 5 female under different living conditions. A total of 314 measurements were performed with Breezing ® , and the results were compared with those by the Douglas bag method.Results: R-squared correlation coefficients (R 2 ) between the data obtained with Breezing ® and the Douglas bag method were 0.9976, 0.9986, 0.9981, and 0.9980, for VO 2 , VCO 2 , EE, and RQ respectively. Conclusions:The EE and RQ values determined by Breezing ® are in good agreement with those by the Douglas bag method.method. Over 300 measurements with human objects were performed following the instructions of the mobile indirect calorimeter and standard protocols of the Douglas Bag method. Statistical analysis methods, such as linear regression and Bland-Altman plot were used to establish quantitative correlation between of the values from the mobile indirect calorimeterand that from the gold standard method. Materials and Methods SubjectsTwelve healthy adults from Arizona State University (ASU), including 7 male and 5 female, were tested during this study. Their ages ranged from 21 to 38 years and their body mass indices (BMI) ranged from 16.9 to 32.2kg/m 2 (Table 1 and Table 2). The study was approved by the Institutional Review Board of Arizona State University (IRB protocol #1012005855) and all subjects participated in the study voluntarily, providing written informed consent prior to participation. The study was carried out at ASU from January 2013 to June 2014. The mobile indirect calorimeter, Breezing ® DeviceThe Breezing ® device uses a sensor cartridge and a flow meter to determine the rate of consumed oxygen and produced carbon dioxide in the breath. The sensing technology of the new indirect calorimeter, which used a cell-phone camera as the optical detector, was previously reported [8]. The current Breezing ® device uses a QR code to carry calibration parameters of a single-use sensor cartridge, which can be scanned and recognized by the mobile application (app). The device is 6.0 oz. (170 g), and 1.8 in × 2.1 in × 4.8 in (4.7 cm × 5.4 cm × 12.3 cm), and connects wirelessly to an iOS mobile device, using Bluetooth 4.0 technology.

Citation: Mora SJ, Mann S, Bridgeman D, Quach A, Xian X, et al. (2020) Validation of a wearable metabolic tracker (Breezing Pro TM ) for Resting Energy Expenditure (REE) measurement via Douglas bag method. Glob J Obes Diabetes Metab Syndr 7(1): 001-008. DOI: https://dx. IntroductionResting Energy Expenditure (REE), also called Resting Metabolic Rate (RMR), has been widely used for fi tness, nutrition and diseases study due to its high importance to body energy balance [1][2][3][4][5][6]. REE is the major component of the Total Energy Expenditure (TEE), determined by basal energy expenditure, diet induced thermogenesis and physical activity Abstract Background and aims: Resting Energy Expenditure (REE) is one of the most important metabolic parameters since it accounts for 60%-70% of total energy expenditure (TEE) in a typical population and 80%-90% in a sedentary one. Accurate measurement of REE is essential for weight control, nutrition management, and disease treatment. Though metabolic carts, desktop metabolic analyzers, and portable metabolic trackers are available on the market to address certain needs of metabolic rate measurement, a stand-alone and truly wearable metabolic tracker that can provide comfortable and natural breathing experience (e.g. lacking of nose clips and mouthpieces) for nasal and pulmonary disease-restricted users is preferred. Here is featured a novel, wearable, stand-alone and fully integrated metabolic analyzer that overcomes the abovementioned user experience barriers. The Breezing Pro TM determines REE based on the indirect calorimetry method. It measures both oxygen consumption (VO 2 ) and carbon dioxide production (VCO 2 ) rates using integrated colorimetric sensing technology. This work evaluates the accuracy of Breezing Pro TM device against the Douglas bag method, considered the gold standard of indirect calorimetry, and validates its functions as the world's fi rst wearable and fully-integrated metabolic tracker, without the need for wearable accessories such as detector back packs, holders, and shoulder straps compared to other predecessors. Methods:A total of 66 healthy subjects under resting conditions were simultaneously tested by Breezing Pro TM and the Douglas bag method. The exhalation rate (V E ), VO 2 , VCO 2 , and REE results from both methods were compared to evaluate the performance of the Breezing Pro TM device. Results:The comparative correlation plots for V E , VO 2 , VCO 2 , and REE indicate a strong correlation between the two methods for measuring the metabolic parameters previously described. R-squared correlation coeffi cients (R 2 ) between the data obtained were close to 0.9 for all parameters. Conclusions:The accuracy of Breezing Pro TM for measuring V E , VO 2 , VCO 2 and REE has been validated using the gold standard Douglas Bag method. The results indicate that Breezing Pro TM is reliable for resting metabolic parameters measurements.