ABSTRACT
Both ergonomists and practitioners responsible for occupational health and safety in a company normally use and appreciate indices of workload and environmental exposures presented in the simplest possible figures and numbers. Therefore, in traditional standards, rules and safety regulations, the physical environment is normally rated in 8-h-based mean values via connecting intensity and duration of stress by means of a multiplication, i.e. a mutual settlement of high load within a short exposure time and a low stress height within a longer lasting exposure. This principle is well-based on the experience that a low workload can be tolerated for a longer duration than a high workload. But does this confirm the hypothesis that equal energy or dose, or equal demanded output, also involves equal short-or long-term human responses? It will be shown that standards and conventional guidelines for occupational health and safety are more closely related to physics than to physiology. Yet, to really protect man at work, ergonomics must be much more concerned with
physiological costs of work and environmental stress than with physical principles of equal energetic dose.
