In view of assessing the physical fitness of Bulgarian men going to work in lumber production in the Komi ASSR (180 men of different professions) the physical working capacity was measured by bicycle ergometer with submaximum loading (50, 100 and 150 W). The maximum aerobic capacity is extrapolated after the nomogram of Astrand and the individual regressive lines. The results point out the mean values of physical working capacity assessed after oxygen consumption and pulse. Frequency at submaximum loading (at 150 W average for the group they are respectively 2, 12 dm3/min and 166 beating/min). The assessment of the physical working capacity after the maximum oxygen consumption is also about the mean (2.7 dm3/min). The representatives of the so called sitting professions (employees, drivers) have lower aerobic capacity then those engaged mainly in physical work (machine building, construction workers). In comparison with literature data the examined persons have lower working capacity for the corresponding age. Juxtaposing the results of the mean data for physical working capacity with the high energy losses in the lumber industry imposes measures for raising the physical working capacity of the Bulgarian workers departing for the Komi ASSr, by effective training system, improving the work and rest regimen, professional selection by examining the physical working capacity etc.