Insensible weight loss as an indicator of metabolic rate

Insensible weight loss has been used in large animals as an index of metabolic rate. By using the microprocessor controlled electronic balance to minimize the effects of movement, the feasibility of utilizing insensible weight loss as an estimate of metabolic rate in the rat is considered in terms of convenience and accuracy. Using various metabolic stimulants, a high correlation between insensible weight loss and metabolic rate was obtained. Moreover, a calculation is described that corrects for respiratory water loss and results in even higher correlations. These findings support the use of insensible weight loss as an indicator of metabolic rate in controlled situations for small animals.