Scand J Work Environ Health 2014;40(2):105-108    pdf full text


Rest breaks – a countermeasure for work-related injuries?

by Sallinen M

The main idea behind supplementary rest breaks within a work shift is to promote recovery from work, a process known to be important for health in the long-run (1). Supplementary rest breaks are also used to promote occupational safety. In many industries and occupations, rest breaks are viewed as so important for safety that their use is determined by legislation and regulations. This holds especially true for the transportation sector where, for example, professional drivers’ work–rest cycles are determined by acts and regulations, recorded by the employer, and inspected by authorities.

For the moment, scientific knowledge suggests that the use of supplementary rest breaks during a work shift can prevent or ease musculoskeletal symptoms and disorders (2, 3) and sleepiness (4, 5) to some extent. Whether also occupational injuries can be reduced by the same intervention is largely unknown (6) even though a recent study on workers who had experienced a work-related ladder-fall ­suggested that rest breaks could be used as a tool to enhance occupational safety (7).

In this issue of the Scandinavian Journal of Work, Environment & Health, an original study examines the association between rest breaks and severe work-related injuries (8). In the study, 703 hospitalized workers from various industries with severe work-related traumatic hand injury were interviewed in three cities in the People’s Republic of China. The study did not include a group of uninjured controls. The main finding of the study was that a rest break of any duration postponed the onset time of a work-related hand injury.

The study has obvious strengths. It is based on face-face interviews that were done shortly following the injuries. In addition, many potential covariates (including age, gender, work hours, work start time and duration, injury day and time, duration and quality of last sleep, sleepiness, and job control) could be evaluated when examining the relationship between time-to-injury and the prior rest break. However, like all studies, this study also has its limitations, many of which the authors raise in the paper.

A central question arising from the study is how to interpret the main finding on the effect of a rest break on the time-to-injury within a work shift. According to the authors, the results “support the use of rest breaks during a work shift, along with other proposed measures to delay the onset time of a work-related injury and potentially counteract the effects of work fatigue as a means of obtaining recuperative rest and enhancing worker safety”.

Taken literally, the first part of the interpretation sounds problematic: Does it really matter whether an injury occurs earlier or later during a work shift if it nevertheless occurs? On the other hand, the latter part of the interpretation says the main takeaway of the study is that rest breaks have potential to help workers recover significantly from fatigue that has accumulated over the preceding work session(s).

The main finding is good news albeit with some reservations. The association found between the time-to-injury and having or not having a rest break before the injury may be explained also by factors other than recuperation through a rest break. It is possible that many of the workers who had no prior rest break simply experienced their injuries before their first rest break opportunity. It is natural that a certain amount of injuries occur during the first hours of the work shift and thus before the first rest break. On the other hand, if a worker is engaged in his or her tasks for a long period of time without having a rest break there may be some particular reasons for this and the same reasons may also contribute to the occurrence of an injury. Third, it is possible that the workers without a prior rest break had, on average, fewer rest break opportunities than their counterparts. This kind of difference between the two groups of injured workers could play a role in the onset time of an injury.

Despite these reservations, which are often inherent in this type of research design, the study of Lombardi et al (8) significantly contributes to the limited body of evidence on the role of rest breaks in work-related injuries. The results can be used as evidence for justifying and introducing the use of supplementary rest breaks. It is also most likely that the results will stimulate further research.

From a practical viewpoint, there are some pertinent questions to be answered regarding the use of supplementary rest breaks. One of the questions concerns the ways in which supplementary rest breaks ought to be introduced and implemented in a workplace. In a study by Oude et al (9), a tool aimed at raising awareness about the importance of supplementary short rest breaks among construction workers did not prove successful. In a later study from the same research project (10), the rest break tool – together with training sessions on workload adjustment and possibilities for greater worker influence at a worksite – did not result in significant improvements in musculoskeletal symptoms, sick leave, work ability, or health. Another study by Sarna et al (11) found that taking rest breaks was strongly associated with smoking status among nurses: those who did not smoke were almost twice as likely to miss their rest breaks as compared to smokers. In light of these findings, it is expected that management’s commitment to flexible rest break practices, regulatory measures, or both are needed to make a difference in rest break practices and policies in the workplace.

Another issue regarding the use of rest breaks is workers’ activities during their breaks. One could hypothesize that workers spontaneously spend their rest break time in a way that facilitates recuperation. The study of Lombardi et al can be considered to support this hypothesis since the rest breaks were associated with a delay in the mean onset time of injuries, even though the researchers did not oversee activities during the rest breaks. However, it is not self-evident that workers would have an opportunity to engage in optimally recuperative activities during rest breaks. A good example of this is the use of nap break opportunities in shift work. Despite the large body of evidence showing that prescribed nap breaks are effective in alleviating fatigue under the soporific conditions of shift work, in many industries and countries, caffeine and even nicotine consumption is still more easily accepted as a fatigue countermeasure than taking a nap.

In the future, there is a clear need for intervention studies to examine rest break practices that would prevent work-related injuries. This need is emphasized by the association of two common phenomena of modern work life, stress and fatigue, with work-related injuries (12, 13).