News Release

Introvert persons are more likely to become tired at work

Peer-Reviewed Publication

Netherlands Organization for Scientific Research

Introvert people have a higher risk of becoming tired than their extravert colleagues. This was revealed in the first large-scale and systematic study into the influence of personality on tiredness, which was carried out by researchers from Tilburg University.

Psychologists from Tilburg University followed more than 700 people for a period of two years. Every six months these employees completed questionnaires concerning personality, styles of coping with problems, (work-related) stress and social support. Demographic aspects, such as having a child, were also included in the study.

The study revealed that after two years, introvert persons have greater a chance of becoming tired than extrovert persons. The degree to which people experience their workload is also significant. Employees who think that they are busy, have a greater chance of becoming tired than colleagues who do not think they are that busy.

The Tilburg study also revealed that the manner in which an individual copes with problems does not influence tiredness. For example, an employee who acts as if a problem does not exist is not more susceptible to tiredness than somebody who is the same in almost every aspect, but approaches and deals with problems in a systematic manner.

Contrary to what was expected, it turns out that physical and mental tiredness are inextricably linked to each other. One cannot be physically tired without being mentally tired and vice versa. The researchers therefore recommend that company doctors include physical tiredness as well as mental tiredness in their investigations.

This is, for example, possible with the new questionnaire developed by the researchers. This combines the advantages of existing questionnaires and is compact and user-friendly. The researchers state that the questionnaire is ideal for screening employees.

Up until now little research had been carried out into the generally held assumption that personality influences the experience of tiredness. This study is part of the Priority programme 'Fatigue at Work', financed by the Netherlands Organisation for Scientific Research.


Further information can be obtained from Dr Helen Michielsen (Department of Psychology, University of Tilburg), tel. 31-13-466-2299, fax 31-13-466-2370, email The defence of the doctoral thesis took place on 13 September 2002. Dr Michielsen's supervisors were Prof. G.L. van Heck and Prof. T.M. Willemsen.

The research was funded by the Netherlands Organisation for Scientific Research (NWO).

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