In miners with chronic bronchitis, diminution of bodily energy reserves does not permit optimizing their functional state in full measure. Patients are provided with ample opportunity to realize various forms of behaviour in order that they might continue their labour activities under usual conditions they are accustomed to. Exclusion from the activity those labour operations of high energy content, lowering of density of work, and increase in duration/number of breaks for rest--all such measures serve to secure professional activity. From the standpoint of self-preservation of the organism the above-named changes can be regarded as quite expedient since they minimize the action of adverse factors of the labour process. Nevertheless, this does not save the miners weakened by their illnesses from development of unfavourable states of overstrain during the process of their work.