Low cardiorespiratory fitness (CRF) is related to higher risk of cardiovascular diseases, increase in all-cause mortality and higher risk of different tumors. The reverse is also true; improvement in CRF is related to decrease in mortality. Cardiopulmonary exercise testing (CPET) is a standard and also the most precise test for determination of CRF - the best possibility is the maximal test measuring different parameters including maximal oxygen consumption. Healthcare professionals throughout the developed world have markedly high rates of sickness absence, burnout, and distress compared to other sectors and this leads to higher risk factors. The study aimed to assess CRF in a group of nurses in a big hospital and compare it with population norms and available published results. Nurses over 50 years of age working in one faculty hospital were gradually included in the study from the beginning of 2018. These nurses work in physically demanding positions. A CPET was carried out following the Bruce protocol. 90 nurses (84 females and 6 males), mean age 55.7 years, were evaluated by CPET. The resting blood pressure was within the norm in 58 persons (64.44%), maximal oxygen consumption in 61 persons (67.8%), W/kg in 25 persons (46.2%). We detected a hypertension reaction in 28 persons (31.1%), some types of arrhythmia in 17 persons (18.9%) and signs of ischaemia in 8 persons (8.9%). The result of CPET led to further examination in 42 persons (46.6%). Detailed examination resulted in change of medication in 21 nurses (23.3%). New diseases were diagnosed in 15 nurses (hypertension, atrial fibrillation, mitral valve prolapse indicated for cardiac surgery, coronary artery stenosis, and lipid disorders). It was concluded that the usage of CPET during the regular medical check-ups significantly increases detection of hidden diseases and thus improves the care for nurses.