Objectives In the change process, workers’ work-related well-being is often seriously challenged, and it is not clear to what extent current occupational health systems are capable of dealing with changes in the world of work. This paper determines how the tools used by occupational health services conceptualize changing work as the object of occupational health activity.

Methods The methodology was based on the Cultural Historical Activity Theory, and the data originated from a development intervention project.

Results The tools used in everyday occupational health activity were utilized to construct the object as the interplay between the worker and the loading factors, but the central phenomenon from the well-being point of view seemed to be the disturbances in the work flow.

Conclusions As long as occupational health services construct their objects according to health-study-based tools only, the activity will not be able to contribute to the prevention of work-related well-being problems in situations of change.

Key terms cultural historical activity theory; object formation; occupational health services; OHS; working life; working life change; worklife; worklife change