Introduction In our modern service economies, considerable groups of workers remain exposed to high physical demands. Many jobs in Europe still involve manual labour and this proportion has hardly changed over the last years. In light of the growing evidence base on the harmful cardiovascular effects of occupational physical activity there is a need for developing preventive measures against premature cardiovascular morbidity and mortality in workers exposed to high physical demands. The aim of this study is to investigate objectively the relation between physically demanding jobs and the cardiovascular health of employees and the possible mediating role of psychosocial work factors.

Methods A field study including ambulatory registrations during 2–4 days of physical activity (PA), heart rate (HR) and heart rate variability (HRV) is conducted in a convenience sample of 450 employees. For optimising the external validity of the findings, the sample is not restricted to particular gender, job types or sectors of employment. Participants are recruited from workplaces within the manufacturing and service sector. Participation is on a voluntary basis with informed consent, and includes questionnaire assessment, medical examination (resting HR, blood pressure, and anthropometric measurements), a fitness test and a minimum of 48 hours field registration.

Result The HRV results will provide different insights in relation to workload, HR reserve (the ability to recover from work tasks) and the cardiovascular health. Given the study design, thorough assessment of confounders is required. Therefore, the baseline questionnaire includes standardised measures of socio-demographic information, physical and mental health status, health behaviours, retrospective sickness absence, overall work ability and negative affectivity.

Discussion Self-report PA instruments are generally known to suffer from poor absolute criterion validity, and fail to capture all relevant PA. This study aims to increase the knowledge of the cardiovascular health of employees in physically demanding jobs with objective measurements.