[Body composition and energy metabolism at rest]

Indicators of body composition determined by bioelectrical impedance analysis (total body water, extracellular water mass, intracellular water mass, skeletal muscle mass, soft lean mass, protein, mineral mass, fat mass) were compared with the resting metabolic rate values (RMR). Studies were conducted in adults of different occupations, gender, age, weight and height. In total, the survey involved 180 people, residents of Nizhny Novgorod (70 men and 110 women) aged 17 to 63 years. It was shown that the normalization of the RMR with the parameters of the bioelectrical impedance analysis reduced the scatter of individual values. Comparison of the normalization results allowed us to estimate the interconnection between the RMR and the body composition. It was obtained statistical formulas for the relation of the RMR with the bioelectrical impedance. The greatest effect was found with the normalization of lean mass, as well as intracellular and extracellular water masses. The smallest effect was detected with the normalization of body fat. We obtained statistical formulas for the relation of the RMR with the bioelectrical impedance parameters. The highest correlations were found between the RMR and the lean mass, muscle mass and total water mass, the lowest with the fat mass. Role of the metabolically active tissue in energy metabolism, including the role of the intracellular and extracellular water is discussed. The results confirm the importance of the metabolically active tissues in the formation of the value of the RMR. Identified dependencies and high correlation between the RMR and the bioelectrical impedance parameters allows us to use these as a fast and convenient method for the approximate estimation of the RMR.