The aim of this study was to determine what proportion of occupationally active Poles have working capacity that enables them to tolerate hard and very hard physical work. For this purpose physical capacity of 1188 occupationally active subjects (524 women and 664 men), aged 18-64 years was examined. Their maximal oxygen consumption (VO2max) was determined indirectly on the basis of their heart rate during an incremental exercise test on a bicycle ergometer. It was found that hard occupational physical work was an excessive load for almost 40% of men and women. This paper discusses how this load should be decreased with planned, appropriately long rest breaks. The percentage of persons for whom their hard physical work becomes an excessive load increases with age to such a degree that a new assessment of individual capability for such work is recommended for persons over 40 years old.