Statistical analysis of the distribution of the mean somatometric, functional, and psychophysiological parameters in the total sample of subjects with the use of the χ2 and λ tests and low, medium, and high habitual physical activity (HPA) levels (LHPA, MHPA, and HHPA, respectively) at different ontogenetic stages (junior and senior school students and young adults of both sexes) showed wide quantitative and qualitative ranges of psychophysiological individuality in a healthy population and demonstrated that it is reasonable to distinguish three typological groups or functional constitutional types (FT-1 corresponding to LHPA; FT-2, to MHPA; and FT-3, to HHPA). Typical first- and second-order parameters, as well as the results of third-order tests characterizing the current state, were determined for each FT. In order to comprehensively assess the constitutional type (synthetic constitution) of the subjects with low, medium, and high HPAs, the integrated analysis of the set of their characteristics was performed using the principles of polythetic (multi-variate) classification. The results obtained using multivariate statistical methods confirmed the basic postulate of the concept of typological variability of physiological individuality that a healthy human population is qualitatively heterogeneous in morphological, functional, and psychophysiological traits. The integrated physiological and statistical analyses of the results provided a scientific basis for three functional constitutional types (FT-1, FT-2, and FT-3) corresponding to three synthetic constitutional types (C 0-1, C 00, and C 01). These data indicate that the systemic (constitutional) approach to the estimation of individual typological characteristics confirm a high informativeness of partial constitution (FT-1, FT-2, and FT-3) in the human biological organization, and the set of characters selected for analysis allows the synthetic constitutional types to be adequately differentiated on a formal basis. © 2011 Pleiades Publishing, Ltd.