The aim of this study is to propose a new wave protocol to identify low-frequency oscillations for evaluating resting energy expenditure (REE) and compare its performance with the 5-min interval abbreviated protocol and standard protocol. Consecutive 20-min indirect calorimetry (IC) was used to collect metabolic data from 23 women and 37 men (between 23 and 43 yr old). Sliding window filter algorithms were used to eliminate noise. Three protocols were used to evaluate REE: averaging the data between two consecutive waves (wave protocol), averaging the second 5-min intervals (interval protocol), and averaging the last 15-min REE (standard protocol). Based on 60 healthy participants' metabolic data, compared with the interval protocol, the wave protocol showed better consistency with the standard protocol. The mean bias (limits of agreement) using the wave protocol was 0.3458% (-7.817% to 8.509%), and that using the interval protocol was -1.720% (-16.06% to 12.62%). The time required to evaluate REE with the wave protocol and interval protocol was measured. The measurement time for the interval protocol was 10 min, while the average measurement time for the wave protocol was 9.75 min. We recommend the wave protocol for estimating REE in healthy people. This abbreviated protocol can identify low-frequency oscillations and consider individual differences to more accurately reflect the baseline REE compared with the interval protocol. When compared with the standard protocol, the measurement time of the wave protocol was reduced by nearly half [from 20 min (standard protocol) to 9.75 min].NEW & NOTEWORTHY For estimating REE by indirect calorimetry, to shorten the measurement time, a consideration of low-frequency oscillations is essential. Based on that we proposed a new abbreviated protocol named wave protocol, which showed accuracy approaching that of the standard protocol with a measurement time close to that of the interval abbreviated protocol.
Keywords: energy expenditure; energy metabolism; indirect calorimetry; protocols evaluating REE.