Impact of flexible working hours on health

A high degree of variability in working hours has been found to correlate with increased risks for health and psychosocial well-being, especially if the variability is company controlled rather than being of the employee’s choosing.

A study (in German, 2.5Mb PDF) by the Federal Institute for Occupational Health and Safety (Bundesanstalt für Arbeitsschutz und Arbeitsmedizin , BAUA) investigates whether the negative effects of flexible working hours on health and psychosocial well-being can be eliminated, or how they could be alleviated by an appropriate design of flexible working hours.

Definition

‘Flexible working hours’ are defined as working time arrangements allowing a continuous choice regarding the duration and the temporal distribution of working time for both the employee and the employer.

A simple deviation from the standard working time is not seen as sufficient for a distinction. The definition intends to exclude shorter but regular working time arrangements such as part-time work or deviating but regular working hours such as shift work.

A classification of a flexible working time model determines four key elements, namely:

• variability of temporal distribution;

• variability of length;

• influence on the arrangement of working hours;

• predictability.

Methodology

The analysis is based on a company survey and an Internet study. For the former, questionnaires were sent to 17 companies and 660 employees in the following sectors: retail trade, services (call-centre), publishing, telecommunication, public administration, manufacturing, and health. The response rate of the 2,159 questionnaires issued was 31%.

For the Internet-based study, 528 responses from various sectors were used for the analysis. The questionnaire on the Internet was similar to that used in the companies. The press and various organisations announced its publication, and, in principle, any person on flexible working time arrangements could respond.

The assumption is that the company-based study displays outcomes that are too positive, while the Internet-based study gives overly negative results, due to an inherent selection bias.

Variability of working time

Both studies demonstrated the same risk patterns. Flexible working hours - both those variable in terms of temporal distribution and in length of work days - result in de-synchronisation effects due to the varying start and end times of working hours, which lead to deviations and disturbances in an individual’s overall time pattern. These, in turn, result in health disorders of circadian regulated functions (sleep, digestion system) as well as psychovegetative disorders related to biological de-synchronisation. The data shows similar impacts as have been found in research on shift work.

The studies show a clear impact of the four determining elements listed above on health and well-being and on work-life balance. Impairments were caused by the high variability and/or lack of influence on the individual organisation of working hours. Effects of biological and social de-synchronisation include health problems and conflicts in work-life balance.

Closely related to the variability of working time is the predictability of working hours. A certain degree of planning, predictability and reliability of working hours can help to avoid a negative impact.

Working time autonomy

The effects of highly variable working hours are moderated by the autonomy of the employees in the individual organisation of their working time, leading to lower health risks.

Sleeping disorders were clearly more prevalent in the context of highly variable working hours than in the case of more regular hours. The impact was even stronger for those workers with a lack of influence over their working hours. Their rates were equivalent to those of shift workers. The workers significantly more often experience a high frequency of colds, back and neck pain, stomach and bowel disorders, and a higher degree of nervousness.

The impact of a high variability of working hours was somewhat compensated for by improved autonomy. An individual influence on working time eases the effects of highly variable working hours. However, workers need to learn or receive training on how to manage working time autonomy in a responsible and reasonable manner.

Comparison with other research findings

The results of the study were compared with the outcome of secondary statistical analysis of the data from the [European Working Conditions Survey 2000](/search/node/ewco OR 3wc OR 3wcindex?oldIndex) in the EU15 on the effects of flexible working hours. Analogous effects of flexible working hours on health and well-being were demonstrated in this analysis and underpin the findings of the BAUA study.

Future research

The data do not allow a risk assessment of specific models of flexible working hours, such as working time accounts compared with sabbaticals, or annual working time accounts compared with flexitime. The analysis recommends a statistical survey on forms and prevalence of flexible working time, taking ergonomic concepts into account and with a longitudinal perspective.

Anni Weiler, AWWW GmbH ArbeitsWelt - Working World