Nieman, D., Trone, G. & Austin, M. (2001, October). Validation of a new handheld device for measuring resting metabolic rate [Abstract]. North American Association for the Study of Obesity.
Melanson, E., Coehlo, L., Tran, Z., Haugen, H., Kearney, J.T., Hill, J. (January 2003). Validation of the BodyGemTM Hand-Held Indirect Calorimeter [Abstract] Presented at Nutrition Week 2003.
ABSTRACT: Validation of a New Handheld Device For Measuring Resting Metabolic Rate
Nieman, D.C., Trone, G., and Austin, M. Validation of a New Handheld Device for Measuring Resting Metabolic Rate. North American Association for the Study of Obesity (NAASO), October 9, 2001.
Objective: The purpose of this study was to assess the validity and reliability of a new handheld device that measures resting metabolic rate (RMR), the BodyGem??? (BG) (HealtheTech, Inc., Golden, CO).
Design: Sixty-three adults (mean±SD, age 41.3±11.2 yr, and body mass index, 26.5±6.6 kg/m2) were tested during 2 separate sessions within a 2-week period, and in each session, 2 BG and 2 Douglas bag (DB) RMR measurements were made in a random and counterbalanced order. The BG uses sensor technology to measure O2 consumption, barometric pressure, temperature, relative humidity, and volume of air, and calculates oxygen consumption. Oxygen consumption is converted to RMR in kcals.day-1 using a fixed respiratory quotient of 0.85 and using a modified Weir equation. In the DB bag method, expired air was collected for 10 min in meteorological balloons, with fractional concentrations of CO2 and O2 measured with Amatek analyzers, total volume with a Rayfield dry gas meter, and RMR estimated using the Weir equation.
Results: Within session reliability for measurement of O2 consumption was high on both days for the BG (r=0.97). During the 4 single tests, BG and DB O2 consumption values were significantly correlated (r=0.81-0.87), with SEEs ranging from 22-28 ml.min-1. Mean O2 consumption and RMR values for all 4 tests were 241±46 and 240±45 ml.min-1 (r=0.91, SEE 18.7 ml.min-1), and 1657±324 and 1650±307 kcals.day-1 (r=0.91, SEE 134 kcals.day-1) for the BG and DB methods, respectively.
Conclusions: These data indicate that the BodyGem is a valid and reliable device for measuring oxygen consumption and calculating RMR during repeated tests within a day, single tests on separate days, or when measurements are averaged.
Key Words: oxygen consumption, metabolism, respiratory quotient, energy expenditure
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ABSTRACT: Validation of the BodyGem Hand-Held Indirect Calorimeter.
Edward L. Melanson1, Ligia B. Coelho1, Zung V. Tran2, Heather A. Haugen3, Jay T. Kearney3, and James O. Hill1
1Center for Human Nutrition and 2Department of Preventive Medicine and Biometrics, University of Colorado Health Sciences Center, Denver, CO. 3HealtheTech, Inc., Golden, CO
Background: Indirect calorimetry has become the standard in research settings by which resting metabolic rate (RMR) is determined, but this method is not a practical option in clinical settings. New technologies are needed in order to provide clinicians with an accurate and easy to use method of measuring RMR. A recently introduced hand-held indirect calorimeter (BodyGem??, HealtheTech, Inc., Golden, CO) is an example of such technology. The purpose of this study was to assess the validity and reliability of the BodyGem, using measurements obtained from indirect calorimetry as the criterion measure.
Methods: RMR was measured on two mornings in 41 healthy adults of varying age (21-61 yrs.) and body fatness (% body fat = 16.1 - 51.5%). On each morning, RMR was measured using both a metabolic cart (SM-2900, model 2900, Sensormedics Metabolic Cart, Yorba Linda, CA) with a ventilated canopy and the BodyGem (BG). Measurements were made in the morning (between 7 and 10 AM), after a 12 h fast and at least 24 h abstention from exercise. Body composition, including fat free mass (FFM), was determined using dual-energy X-ray absorptiometry.
Results: There were no trial-to-trial differences in RMR measured by the BG (1614 ± 39 vs. 1600 ± 39 kcal.d-1) or the SM-2900 (1529 ± 39 vs. 1528 ± 40 kcal.d-1). Trial-to-trial intraclass reliability coefficients were acceptably high for both the BG (R=0.92, 95% CI=0.85 to 0.96) and the SM-2900 (R=0.97, 95% CI= 0.94 to 0.98). RMR measured by the BG was significantly higher than that measured by the SM-2900 during both trial 1 (mean difference, 85 ± 18 kcal.d-1, p<0.0001) and trial 2 (72 ± 19 kcal.d-1, p<0.0001). When averaged across the two trials, RMR measured by the BG (1607 ± 37 kcal.d-1) was significantly higher (5.1%) than the SM-2900 (1529 ± 39 kcal.d-1), although the two were highly correlated (r=0.92, p<0.0001). FFM was strongly correlated with RMR measured by the BG (r=0.86, p<0.0001) and the SM-2900 (r=0.90, p<0.0001).
Conclusion: Measurements of RMR obtained with the BG hand-held indirect calorimeter compare favorably with measurements obtained with indirect calorimetry coupled with the ventilated canopy technique, although the BG tended to produce values significantly higher than the SM-2900. A portion of the elevated RMR measured by the BG may have been due to the slightly different body position used during testing.
