The paper provides a biorhythmological assessment of the health of a driver's team in conditions of joint activity in terms of heart rate variability. Measurements were taken during the working day using Holter monitoring in AnnaFlash2000 software and statistical processing ISCIM6. The cardiogram of the heart was recorded during the working day from 8.00 to 18.00 hours. It was revealed that the rhythmic processes of acrophase and heart rate bathyphase, which testify to the leading role of hypoxia, hypercapnia and desynchronosis of ultradian rhythms, influence the joint professional activity of drillers. The examined drivers found a violation of the synchronization of biological rhythms and desynchronosis at various levels of regulation of heart rhythm regulation. Both drivers, working in different biological rhythms, have a low degree of compatibility and belong to the group of production risk, which negatively affects occupational safety. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).