The purpose of the research was to determine the association between hair heavy metal levels in children of different ages with the level of functional reserves of the organism in Moscow. Two groups (n = 78) of healthy boys living in Moscow aged 4 - 6 and 7 - 11 years were examined. Hair levels of Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb were assessed using atomic absorption spectrometry. Functional reserves of the body were estimated using computer spirometry and analysis of heart rate variability. Hair heavy metal content in children aged 7 - 11 years was significantly higher than that in the younger children for the majority of the elements studied, especially Cr, Fe, Zn, and Cd, whereas hair Ni content was higher in the younger children. Hair iron content significantly correlated with age (r = 0.38, p < 0.05). In contrast, the parameters of respiratory and cardiovascular function were increased in the older children. Therefore, the observed levels of inorganic pollutants in the hair of children did not significantly affect the growth and development of the organism and the formation of functional reserves. However, adverse health effects may occur at higher rate of urban environment pollution, being typical for certain areas of Moscow.