Working Conditions and Health Status of Fixed Night Shift Workers at Logistics Centers (2024)

The Korean Public Service and Transport Workers’ Union (KPTU)

Korea Institute of Labor Safety and Health

Translated by Heeun Lee

Reviewed by Joe DiGangi

1. Research Background and Methods

Many workers at logistics centers work the night shift. Due to higher wages on the night shift, workers prefer night work to day work. However, the high intensity of work at logistics centers, coupled with poor working conditions such as exposure to extreme temperatures, compromises workers’ health. The number of workers engaged in non-rotating night shifts for 20 days or more per month is increasing. This study aims to examine the health effects of night shift work. Additionally, the study evaluated the regulations governing night shift work in South Korea and several other countries to identify necessary legal provisions in South Korea. Through surveys and interviews, the study examined the employment history, health status, and willingness to switch to daytime work of logistics center workers engaged in fixed night shifts. The study aimed to identify the social structural context that leads workers to continue night work despite its adverse health effects, explore measures to minimize health damage, and ultimately propose solutions to improve the structural factors that threaten worker health.

2. Health Effects of Night Work & Review of Domestic and International Night Work Regulations

Numerous studies have confirmed that night work has adverse effects on both physical and mental health. It raises blood pressure and impairs the normal nighttime decline in blood pressure, thereby increasing the risk of cerebrovascular and heart diseases. Night work also contributes to the development of diabetes and hinders blood sugar regulation. In addition, it reduces concentration, negatively impacting work performance and raising the risk of workplace accidents. Disruption of circadian rhythms due to night work has also been linked to poor sleep quality and decreased physical stamina.

Regulations on night work in various countries, including those by the International Labour Organization (ILO) and the European Union (EU), have been reviewed. First, ILO Convention No. 171 states that when night work is unavoidable due to industrial changes and other factors, it must ensure the safety and appropriate working conditions for both men and women, including provisions for health examinations and job rotation. The EU also guarantees the right of workers to transfer to daytime work if night work negatively affects their health. In France, night work is generally prohibited but may be permitted in exceptional cases when social and economic needs are balanced with the health and safety of workers. Notably, some European countries also impose restrictions on supermarket operating hours to limit night work.

In contrast, the South Korean Labor Standards Act does not directly restrict night work. Instead, it takes an indirect regulatory approach, requiring employers to pay a premium of at least 50% of regular wages for night work. Additionally, the Industrial Safety and Health Act mandates special health examinations for night workers. However, unlike the ILO and European standards, South Korea lacks regulations that effectively prevent the excessive use of night work. Previous studies have emphasized the need for restrictions on consecutive night shifts, limits on the number of night shifts per month, and guaranteed rest periods.

3. Results: Survey

A survey was conducted among 270 night shift workers at logistics centers—including Daiso, the Central Distribution Center of the Post Office, Coupang Logistics Center, and others—and the results were analyzed. The most common form of employment was indefinite-term contracts, accounting for 51%, followed by fixed-term contracts at 31%, and daily wage employment at 5.6%. On average, workers were on duty for 9.4 hours, with meal breaks averaging 52 minutes and rest breaks averaging 55 minutes. Given the increased fatigue associated with night work, it appears necessary to ensure longer rest periods.

The main reasons for choosing night work (multiple responses allowed) were higher wages compared to the same working hours during the day (66%), followed by the convenience of having free time during the day (26%) and the opportunity to hold a second job (20%). These responses suggest that economic factors are the primary motivation for engaging in night work.

Respondents reported a range of health problems after working in logistics centers, including sleep disorders, fatigue, weight loss, vision impairment, and gastrointestinal issues. While a majority (69%) believed that night work has a negative impact on health, only a minority expressed a strong desire to switch to day shifts (14% strongly agreed; 27% agreed). The main reason for this reluctance was the unwillingness to accept a reduction in wages (68%).

Although the high work intensity in logistics centers is widely recognized, the subjective work intensity reported by night shift workers in this study was also significant, averaging 14.33 on a scale where this level falls between “the difficulty of walking quickly” and “the difficulty of running 100 meters.” Even during nighttime hours, work intensity was found to be higher than that of daytime shifts, indicating a need for measures to reduce physical demands during night work.

Regarding sleep patterns, 34% of respondents reported difficulty falling asleep daily or several times a week, while 37% reported frequent waking up during sleep, highlighting common sleep disturbances among night workers. Interestingly, the prevalence of certain health issues was slightly lower among those who had worked at night for longer periods, which may be attributed to the “healthy worker effect.” In other words, those who remain in night work for extended periods are more likely to be individuals whose health has enabled them to survive the demanding conditions.

Lastly, respondents expressed high levels of dissatisfaction with their current jobs, particularly in relation to reward and workload. The top priorities identified for improvement included enhancing employment status, reducing night work hours, improving working conditions, and increasing wages.

4. Results: Interview

Four in-depth interviews were conducted, along with group interviews involving a total of 20 participants at each site. The logistics centers where the interviewees worked included the Eastern Seoul Postal Distribution Center, Daiso Namsa Center, Bupyeong Postal Logistics Center, and Coupang Incheon 4 Center.

The interviews revealed that low entry barriers and night shift premium were the main factors attracting workers to these jobs. Because night shifts include additional payment, many workers chose night work for economic reasons and did not consider daytime shifts as a viable option. Despite the long working hours, physical strain, and high-intensity demands of night shifts—often involving prolonged standing and constantly moving—many workers also held second jobs.

Most interviewees reported experiencing sleep disorders. Due to the interruption of the day-night cycle, workers said they were unable to sleep continuously and often woke up intermittently. Aside from sleep problems, few workers reported serious health conditions. One interviewee observed that many people start the job and leave shortly after, while those who had been employed for more than two years appeared to be the ones who had managed to adapt and survive.

Despite the physically demanding nature of the work, the logistics centers often failed to consider workers’ comfort, especially regarding temperature control. Some interview sites were located in underground parking areas with no air conditioning. Ironically, even after working at these centers for quite a long period, most workers did not view the logistics center as “my workplace” where they envisioned staying long-term. Consequently, they lacked the motivation to push for improvements or participate in labor unions.

Unless viable alternatives to night work—which is detrimental to health—are provided, workers will continue to take night shift positions at logistics centers, and safety and health problems will remain unresolved.

5. Conclusions and Recommendations

Logistics center workers are aware that working fixed night shifts is detrimental to their health, yet many continue to do so. The primary reason is the economic incentive of higher wages associated with night work, compounded by the lack of alternative daytime jobs offering comparable pay. To protect workers from the harmful effects of night work, the following recommendations are proposed:

First, regulations should be established to reduce night work to protect workers’ health and safety. The current situation—where workers are compelled to take night shifts for financial reasons despite health risks, and companies take advantage of this—must be reformed. Regulations should include limits on consecutive night shifts, the right to request transfer to daytime work for health-related reasons, increased rest periods, and reduced work intensity.

Second, efforts should be made to gradually eliminate or reduce night workloads and improve conditions so that workers can earn a living wage through daytime work alone, thereby making daytime work a viable option.

Third, the labor intensity of logistics center work must be reduced by expanding the workforce.

Fourth, stable employment structures should be established. Despite the high predictability of logistics volumes, the proportion of temporary workers remains excessively high. Regular employment should be introduced to ensure a stable workforce and maintain efficient logistics operations.

Fifth, adequate rest periods must be guaranteed, working conditions at logistics centers must be improved, and a comprehensive system for managing workers’ health should be established. To reduce work intensity, rest breaks during night shifts should be extended, and appropriate rest areas must be provided. Additionally, work environments should be improved to protect workers from extreme temperatures, and medical support and job reassignment options should be available for those with health concerns.

Sixth, social pressure must be applied to the logistics industry to foster internal self-regulation. There is an urgent need to address the harsh working conditions driven by a 24/7 consumer society and the social problems stemming from the rapid expansion of the logistics sector. It is necessary for our society to develop the capacity to regulate the logistics industry, which is engaged in a relentless race against time.