Methods for Estimating Resting Energy Expenditure Using Indirect Calorimetry in Adults with Overweight and Obesity (P13-030-19)

Abstract

Objectives

Standard procedures to estimate resting energy expenditure (REE) using indirect calorimetry are time-consuming, and may be unnecessary. Indeed, the guidelines recommend a pre-test resting period of 30-minutes, followed by a 5-minute stabilization period, and then waiting until the first steady state period (SS), defined as a 5-minute period with a coefficient of variance (CV) of <10% for VO2 and VCO2, to estimate REE. The aim of the study was to evaluate alternative procedures for estimating REE in adults with overweight and obesity.

Methods

Indirect calorimetry was performed in 37 adults enrolled in a weight loss trial using a metabolic cart (Quark RMR, COSMED). The volume of oxygen (VO₂) and volume of carbon dioxide (VCO₂) were collected every 10 sec for ≥20-minutes following pre-test resting (10-mins) and stabilization (5-mins) periods. The measurement period was segmented into five-minute (REE_6–10, REE_11–15, REE_16–20, and REE_21–25) and rolling (REE_6–15, REE_6–20, and REE_6–25) periods, and VO₂, VCO₂, and CV were calculated for each period. REE was calculated using standard criteria (REE_SS). Alternative SS periods of 3- and 4-minutes (REE₃ and REE₄) were applied to those who did not achieve REE_SS. REE_SS estimates were compared to the other estimates of REE using paired t-tests.

Results

Participants were 51 ± 14_SD yo, primarily women (78%), and had a BMI of 35.4 ± 5.5_SD kg/m². REE_SS was achieved by 81% (n = 30) of all participants, and 54% (n = 20) achieved REE_SS during the first 5-minute period (REE_6–10) following stabilization. Applying REE₃ and REE₄ criteria, those who did not reach REE_SS increased to 92% (n = 34). There were no significant differences between REE_SS, and REE₃ (P = 0.21), REE₄ (P = 0.40), REE_6–10 (P = 0.38), REE_6–15 (P = 0.15) or REE_6–20 (P = 0.05).

Conclusions

The majority of adults with overweight and obesity met the standard criteria for SS following a reduced pre-test resting period. However, the non-significant difference between REE_SS and rolling averages suggest the standard criteria may be unnecessary in a group setting.

Funding Sources

American Heart Association.