A method is provided for correcting reference parameters based on weight variations of a subject. The parameters that can be corrected may be metabolic rate, metabolic equivalent (MET), dehydration rate, drug dosage, exercise intensity, calorie usage, work level, and oxygen consumption. A corrected parameter for a subject can be determined by the factor
to obtain a corrected parameter (Ps). In the factor, wts is the weight of the subject, x is preferably ⅓, Pr is the reference parameter to be corrected, and y is preferably (wtr)z, wherein wtr is the reference weight and z is preferably ⅓.