Thirty Minutes of Physical Exercise May Contribute to the Maintenance of Total Sleep Time in Shift Workers

Keywords

shift workers - physical exercise - sleep

Introduction: Shift workers may have chronic sleep restriction, reducing sleep duration to an average of 5 and 6 hours per day (Narciso; Teixeira; Ohayon; Smolensky; Roth, 2010), presence of sleep disorders, physical complaints and fatigue (Moreno; Lowden; Vasconcelos; Marqueze, 2016) that compromise worker health and safety (Mello; Narciso; Mello; Ruiz, 2015). Workers on the night shift or on rotating shifts mostly have chronic sleep restriction and are usually involved in activities that make routine and regular physical exercise difficult, which can have positive effects on sleep. Physical exercise can still be considered a zeitgeber capable of stimulating specific effects on circadian rhythms and the central molecular clock machinery (Kemler; Wolff; Esser, 2020).

Aim: The aim of this study was to investigate the effect of 30 minutes of physical exercise with vibration on the sleep of shift workers.

Methods: This study was approved (protocol No. 97394818.6.0000.5149) by the Research Ethics Committee (COEP) of the Federal University of Minas Gerais. Participated in the research, 23 male volunteers, aged between 18 and 50 years old, fast rotating shift workers 4 × 1 off-road truck operators in mining company. Participants' sleep was assessed by the actigraphy method for 15 days. Then the participants were randomly allocated to the exercise group on an oscillating platform or the control group. The intervention phase consisted of performing three physical exercise sessions per week, lasting ~30 minutes per session. After the intervention or control period, the volunteers had their sleep evaluated by the actimetry method for another 15 days. The generalized linear model (GEE) with Gamma distribution was applied to describe the effect of group and time on measures of sleep assessed by actigraphy. The variables group and time were considered as a fixed effect, controlling for age and the length of time working on the scale.

Results: Only the variable of total sleep time showed a significant result (Wald Chi-Square 7.59, degrees of freedom:3, p = 0.05). A reduction of ~32 units was observed in the overall mean of the control group at post-treatment compared with pre-treatment.

Conclusions: The proposed physical exercise did not improve sleep parameters evaluated by actigraphy in shift workers. However, those who did not exercise reduced their total sleep time. Physical exercise can help to maintain sleep behavior and total sleep time in shift workers.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
15 June 2023