Portugal: Effects of shiftwork

Conventional working hours in Portugal have become less common in the last few decades and shift work and night work is increasingly prevalent. A recently published study aims to look at how organisations can improve the effects of shift work on their workers, particularly in the way such work is organised.

About the study

A study to examine the effects of shift work conducted in Portugal, Horários de trabalho por turnos: Da avaliação dos efeitos às possibilidades de intervenção [Shift work schedules: From effect’s evaluation to intervention possibilities], uses three examples; one of a company in the electronics sector (company A) and two in the textile sector (companies B and C). It assesses some of the effects typically associated with shift work on:

  • health;
  • family;
  • social life;
  • satisfaction with work.

A total of 859 shift workers from the three companies were involved in the study. The scales used included those published in the literature and those developed by the research team.

Table 1 provides an overview of the socio-demographic characteristics of the workers participating in the study. Their average age was between 36 and 39 years and, in all cases, at least two thirds of the workers were married and had children. In the textile companies, most workers were male while, in the electronics firm, most workers were female.

Table 1: Sociodemographic characterization of workers (%)



Company A (N=490)

Company B (N=122)

Company C
















Level of education

First cycle of basic education




Second cycle of basic education.




Third cycle of basic education




Secondary education,




Higher education




There is an unequal distribution of the number of men and women among the various types of shift. The fixed night shifts are performed mainly by men (in companies B and C); the daytime shifts (fixed mornings and afternoons) are performed mostly by women (in companies A and C).

Male workers predominate in all the shifts in company B; however, women predominate in the conventional daytime working schedule. Also significant is the gender distribution in company A; unlike the other two firms, it has a predominance of women in the fixed night shift, while men predominate in the rotating shifts.

The survey integrated scales to evaluate issues such as:

  • health (sleep, digestive disorders and psychological strength);
  • work schedule and life outside of work (satisfaction with marital, family and social life);
  • support (from family, the employee’s superiors and the company);
  • satisfaction with working hours.

The assessment of support given to employees was made from face-to-face interviews with shift workers using a scale, developed by the authors, which aimed to assess their perceptions of the support they were given in managing issues related to working time. These issues include:

  • the adoption of flexible human resources management practices
  •  the way shift work is organised;
  • resources made available to shift workers.
Table 2 : Effects assessed in each company

Companies A and C

Sleep problem

Digestive problems

Psychological strength*

Life outside the company

Satisfaction with working hours

Company B

Family life

Marital life

Life outside the company

 Satisfaction with working hours

Note: *Only in company A.

Key findings

The relationship assessed in each case, between the perception of support given by the organisation and the different effects of shift work, was conducted using Pearson's correlations. The results can be seen in Table 3.

Table 3: Correlations between effects and the perception of support


Company A


Company B


Company C


Sleep problems




Digestive problems




Psychological strength




Life outside the company




Family life




Marital life




Satisfaction with working hours




Notes: *p < .05; ** p < .01; ***p < .001

The results lead to the conclusion that, in the three cases, there is a statistically significant association between all effects assessed and the perceived support. This oscillates between -.19 with ‘sleep problems’ (Company C) and .47 on ‘life outside the company’ (Company A).

The associations between perceived support and the remaining variables were as expected. This was negative in the case of health problems (sleep and digestive problems); positive for satisfaction with life outside the company in general and with marital and family life in particular; and positive for satisfaction with working hours, as well with ‘psychological strength’ (the ability to perceive everyday life in a positive and optimistic way). Overall, comparing the different dimensions assessed, the intensity of the associations with aspects of life outside the company tends to be slightly higher compared with dimensions related to health aspects.

A descriptive analysis of the variable ‘perception of the organisational context support’ was also made in each company (using a scale of 1 to 5, with 5 being the highest). The results are in Table 4.

Table 4: Descriptive statistics of the perception of support

Perception of the organisational context support

Company A


Company B


Company C


Means (Standard deviation)

Range observed

3.03 (.86)


1 - 5

3.31 (.87)


1.2 - 5

3.32 (.87)


1 - 5

In general, the results point to similar average values in the three cases, especially between companies B and C. On the other hand, and considering the dispersion indicators, the results also suggest variability in the perceptions of this support by the shift workers.


In Portugal, over the last few decades, the workforce has become increasingly feminised and there has been a growing adoption of non-standard working hours, such as shifts or night work.

The organisation of working hours, especially when this involves working at night or during unsocial hours, may represent increased difficulties for a worker in physiological, psychological and/or family/social terms.

The study does not ignore the potential advantages of shift work for employees, but it does focus on the negative effects. The study aimed, in particular, to analyse the workers’ perception of how well a company tries to match workers’ individual preferences and needs to the needs of the company through the use of flexible human resources management practices.

The authors also refer to other possible intervention strategies identified in the literature that can be used by organisations to promote the workers’ adaptation to shift work, and night work in particular. These include:

  • organising shifts to allow naps during working hours;
  • expanding the opening hours of childcare services;
  • not making abrupt changes in the assignment /organisation of shifts;
  • organising the shifts well in advance, so that they can be altered easily if necessary;
  • reinforcing a team spirit;
  • the existence of social support.

Another strategy is to provide information and training for workers about the possible effects of shift work on one’s health, family life, and social life.

Support can also be provided through resources such as canteens, transport or health checks. In the companies where data was collected, it was found that in companies A and C there are, respectively, a canteen and a bar open at night, thus offering the opportunity for hot meals (although a light meal only in the case of Company C). Transport services were provided only by Company A. In all companies, health checks are ensured by the occupational health procedures required by Portugal’s labour laws.


Silva, I., Prata, J. and Ferreira, A. I. (2014), ‘Horários de trabalho por turnos: Da avaliação dos efeitos às possibilidades de intervenção’ [Shift work schedules: From effect’s evaluation to intervention possibilities], International Journal on Working Conditions, No. 7.

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