The table in this article shows the approximate weight and metabolic rate (MR) of the liver, brain, heart, kidney and muscle. Taken as a whole, the intense activity of these five organs affects the daily caloric expenditure, in basal conditions, by approximately 80%.
The values refer to an adult man of 70 kg and a newborn of 3.5 kg.
By basal conditions we mean a particular state of controlled rest, in which the subject is awake, in conditions of thermal neutrality and total psychophysical relaxation, fasting for at least 12-18h.
The neonatal metabolic values were calculated by multiplying the adult ones by the respective weights of the individual organs; although the basal metabolic rate thus calculated is close to that proposed by Benedict & Talbot (750 kJ or 180 kcal), it could underestimate its real value.
Metabolic rate of various organs and tissues in adults and newborns
(kg)
kJ (kcal)
kJ (kcal)
MR
(kg)
kJ (kcal)
MR
Weight of the various organs according to Boyd
Distribution of brain, liver and muscle metabolic rate as a percentage of total basal metabolism at different body weights (HOLLIDAY, 1986).
CHANGES IN BASAL METABOLISM WITH AGE (Mitchell, 1962)
