We calculated a theoretical vitality function as a reference curve, based on experimental results from 226 healthy individuals. This can be used to assess biological aging rates of geographically separate human populations. Only six parameters were used to assess vitality. Each parameter is associated with one of the two physiological compartments. We assume that one compartment keeps the system stable and the other maintains system fidelity. The results permit us to compare vitality curves within populations as well as to determine the age at which maximum vitality appears in each population. The differences between biological and chronological ages in each population and possible etiological interpretations are discussed. This mathematical model can be useful as a method to measure differences in aging rates and effects of aging in several human populations.