Resting metabolic rate in muscular physique athletes: validity of existing methods and development of new prediction equations

Abstract

Estimation of resting metabolic rate (RMR) is an important step for prescribing an individual’s energy intake. The purpose of this study was to evaluate the validity of portable indirect calorimeters and RMR prediction equations in muscular physique athletes. Twenty-seven males (n = 17; body mass index (BMI): 28.8 ± 2.0 kg/m2; body fat: 12.5% ± 2.7%) and females (n = 10; BMI: 22.8 ± 1.6 kg/m2; body fat: 19.2% ± 3.4%) were evaluated. The reference RMR value was obtained from the ParvoMedics TrueOne 2400 indirect calorimeter, and the Cosmed Fitmate and Breezing Metabolism Tracker provided additional RMR estimates. Existing RMR prediction equations based on body weight (BW) or dual-energy X-ray absorptiometry fat-free mass (FFM) were also evaluated. Errors in RMR estimates were assessed using validity statistics, including t tests with Bonferroni correction, linear regression, and calculation of the standard error of the estimate, total error, and 95% limits of agreement. Additionally, new prediction equations based on BW (RMR (kcal/day) = 24.8 × BW (kg) + 10) and FFM (RMR (kcal/day) = 25.9 × FFM (kg) + 284) were developed using stepwise linear regression and evaluated using leave-one-out cross-validation. Nearly all existing BW- and FFM-based prediction equations, as well as the Breezing Tracker, did not exhibit acceptable validity and typically underestimated RMR. The ten Haaf and Weijs (PLoS ONE, 9: e1084602014 (2014)) and Cunningham (1980) (Am. J. Clin. Nutr. 33: 2372–2374 (1980)) FFM-based equations may produce acceptable RMR estimates, although the Cosmed Fitmate and newly developed BW- and FFM-based equations may be most suitable for RMR estimation in male and female physique athletes. Future research should provide additional external cross-validation of the newly developed equations to refine the ability to predict RMR in physique athletes.

Indices of Resting Metabolic Rate Accurately Reflect Energy Deficiency in Exercising Women

“…Additionally, our results demonstrate that lean body mass and fat-free mass should not be used interchangeably within the Cunningham equations, as these equations generated RMR values that were significantly different from each other. These findings indicate that previous researchers may have reported falsely elevated predicted RMR when substituting fat-free mass into the 1980 equation, which was originally intended for lean body mass (Jagim et al, 2018;Staal et al, 2018;ten Haaf & Weijs, 2014;Thompson & Manore, 1996;Tinsley et al, 2019). Importantly, when using fat-free mass with a Cunningham equation, the 1991 equation should be used, but a RMR ratio >0.90 is necessary for higher sensitivity.…”

“…Interestingly, two different Cunningham equations exist (1980 and, one of which relies on lean body mass and the other on fat-free mass. However, there are several examples of researchers using fat-free mass in the calculation for the Cunningham 1980 equation (Jagim et al, 2018;Staal et al, 2018;ten Haaf & Weijs, 2014;Thompson & Manore, 1996;Tinsley et al, 2019), a method that was developed to specifically use lean body mass to estimate RMR (Cunningham, 1980). Whether or not the use of lean body mass and fat-free mass interchangeably may impact the result of predicted RMR and RMR ratio is unknown.…”

Monitoring the Effectiveness of Personalized Metabolic Correction in Athletes Using Biocrystallomics Techniques

“…These trends, which consist in optimizing the crystallogenic properties of athletes' blood serum after a course of individualized metabolic correction, are reflected in the expression of the marginal zone as an indicator of the state of the proteome of the biosensor [4][5][6]. In this case, a significant expansion of the marginal zone of serum micro-preparations was observed (Fig.…”

“…t is known that intensive physical training and high competitive activity, characteristic of highly qualified athletes, contribute to the emergence of various dysregulatory pathologies in the latter [1], [2]. This is manifested in the formation of shifts in the functional state of the cardiovascular system and parameters of cell and tissue metabolism [3], [4], [5]. This trend fully applies to oxidative metabolism, providing in some cases the formation of oxidative stress of varying severity [6], [7].…”

The role of infrared thermography (IRT) and magnetic resonance imaging (MRI) in brown fat evaluation and their application to study the effect of thyroid status on brown fat activity and white fat partitioning

“…In this regard, we are aware that a few companies have attempted to miniaturize indirect calorimeters to instruments that are small enough to be handheld. One such indirect calorimeter is the Breezing calorimeter which is as small as a Wright's peak flow meter and readily portable with one hand (Tinsley et al, 2019). We anticipate that someday in the near future, such indirect calorimeters may even be miniaturized to be used as a mobile smartphone accessory attachment so that it becomes readily available to the general public.…”