An investigation of sleep quality, mental health and job satisfaction among shift workers in South African logistics industry.

Abstract

South Africa hosts an immense human population - one that requires goods and service provision on a vast scale and a rapid timeline. Swift goods and service delivery necessitates an expansive logistics industry which operates on a 24/7 timeline. The employees who drive the logistics industry, known as shift workers, are responsible for ensuring that the local and global supply chains are well-oiled and constantly moving. However, the impact of the act of working in shifts denotes that these employees work odd hours, during the night, at different times every day and rest at abnormal hours of the day. Shift workers are known to experience unusual hours of work which can have implications on their physical health. For example, these could be irregular sleeping patterns and unhealthy lifestyles, and simultaneous disruption of their personal lives. The physical impact of shift work often has an unpleasant effect on the mental and emotional health of such employees, further impacting the feelings that a shift worker has toward the job. This study aimed to investigate sleep quality, mental health and job satisfaction of such shift workers in the South African logistics industry, such that a greater understanding can be obtained about the health of such employees in a relatively underexplored realm of South African research. This investigation additionally unearths the relationships between the constructs of sleep quality, mental health and job satisfaction and distinguishes if sleep quality is a mediator between the constructs of mental health and job satisfaction in shift workers. This study followed a quantitative research design, utilising the theoretical frameworks of the Herzberg Two-Factor Analysis, Broaden and Build theory of Positive Emotions and Spielman’s Three-Factor Model. The construct of sleep quality was measured through the Pittsburgh Sleep Quality Index, the construct of mental health was measured through the General Health Questionnaire -12 and the construct of job satisfaction was measured through the Minnesota Satisfaction Questionnaire – with the biographical data obtained from a biographical questionnaire. A sample of 102 (N=102) was utilised for this study and was obtained from a national South African logistics company. Results of the study indicate that the levels of sleep quality and mental health of these shift workers were poor, whilst the level of job satisfaction experienced was on the positive and more inclined to good levels of job satisfaction. Additionally, the results of the study indicate that relationships between all three constructs are present and that sleep quality is a mediator of mental health and job satisfaction of such shift workers. A secondary test known as Sobel’s Test, was conducted to confirm that sleep quality is a mediator between mental health and job satisfaction. Limitations presented throughout the study related to the data collection process with physical pen-and-paper questionnaires, the time frame to collect data and the additional external challenge of navigating research during the COVID-19 pandemic. Health Questionnaire -12 and the construct of job satisfaction was measured through the Minnesota Satisfaction Questionnaire – with the biographical data obtained from a biographical questionnaire. A sample of 102 (N=102) was utilised for this study and was obtained from a national South African logistics company. Results of the study indicate that the levels of sleep quality and mental health of these shift workers were poor, whilst the level of job satisfaction experienced was on the positive and more inclined to good levels of job satisfaction. Additionally, the results of the study indicate that relationships between all three constructs are present and that sleep quality is a mediator of mental health and job satisfaction of such shift workers. A secondary test known as Sobel’s Test, was conducted to confirm that sleep quality is a mediator between mental health and job satisfaction. Limitations presented throughout the study related to the data collection process with physical pen-and-paper questionnaires, the time frame to collect data and the additional external challenge of navigating research during the COVID-19 pandemic.