KSOEM
Articles
- Page Path
- HOME > Ann Occup Environ Med > Volume 35; 2023 > Article
-
[Special Collection] Working hours as a social determinants of workers' health
Brief Communication Working hours and the regulations for night shift workers -
Tae-Won Jang
-
Annals of Occupational and Environmental Medicine 2023;35:e19.
DOI: https://doi.org/10.35371/aoem.2023.35.e19
Published online: July 5, 2023
Department of Occupational and Environmental Medicine, Hanyang University College of Medicine, Seoul, Korea. JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/ |er˭|I|-fGK.rΛp8XV1%K6mvG+tc+qE &ǸC_Nm:l=_/m5^[dߌڇ.c<%:)tQ$Ow~-aY;UJ >=F)2[nk؆?훐 M=l6[4(O.]2#-H^n#->&mp5~Fӛ+|| S,xag% qkEUzUgæBhߕP(7]kFnq?֖Cpru Z6*rEڊtS|*tI*E}7R<,nUU֫^I7Q*mSly%rdȓd8hE<9oHhMfNSRj[i7D[Rj݊+kდq{"$$H?p \̅S?㭻;t~ R߁ )^/>Qj`yt[w ԛ;² ~+ ߔ_ YW~|o] ?x^ᯛ `ʼn;g)T@vWn]>&4l p+$D̢1l|ȨF%-} .9[}w~
ԠLM9hСablfe&QoW !s ?wjLK?s7yO>(=C~_nyǜu? v 3vyo oI@qV-jeES^[9WoSܝh"l2C1a͔CiJ@3:Pճw= /7ovuk+\V;lDgն <[A+r X~d;m!_s8ݖ;;.0llUC+?i#_crʙ1~C.\q u l8Hܶ2m`ܻM3Tov|Bs rɵ"oLS-
DКw=Tv@f '6|YlD͓Y%-#Ѯo%:&!3o%\J<02;K87>^vgƓ# ;ݝmz^Y6=PS39U%~
&f#
}o!muH; ʲŇ˷yvP+&.7e[3'vR4Yj̗IZ`e˽3o[WU{
m[sUbۋZǾۆl6~9'V*.\S2<Sd*zY[aŶ`]C$n.v^Ʌ
dng>ەZ,Mmϑ :n6nϦezW qUJ4! ۇ4R! =>>F n|Q[{pRO 17ƕ~._I ''00k=b՛o}Osðc2'o\3}ݭQ^ 2 . R1yKȣtAݿ-u ܾw!`?1Whn|gzU o[ECWwjUIן)^h#1ɭ!/Z
np;o;ΗŻkXs."6E`Z1
עӐ9Kl8qd q} 2Stt;#j>;խabONŗ=fwP1j)l6J̶|gV 2`y/0E˛6+ԫ1?
6}KW c\KoKͨ2ۅFws*TԞLיuDx .kCzWXhy۶gLu|%TnupǺl-S* P RaLnT+c+*xl.v!.U=|; !_L̎뱚U=4hm:ٯ"y)$:>%(n}X'p[ȴ
^˒4kƓmzDx
\
'Nq amP7nyN݅=
- Correspondence: Tae-Won Jang. Department of Occupational and Environmental Medicine, Hanynag University College of Medicine, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea. om1024@hanyang.ac.kr
• Received: April 17, 2023 • Revised: May 18, 2023 • Accepted: June 21, 2023
Copyright © 2023 Korean Society of Occupational & Environmental Medicine
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
- There are several types of shift work in Korea: rotating shift, 24-hour shift, day-night shift, fixed night work, and.so on. As a result of analyzing the 8th Korea National Health and Nutrition Examination Survey and the 6th Korean Working Condition Survey, Korean shift workers accounted for 11.6%–13.9% of wage workers. Weekly working hours of shift workers were 57.69 ± 1.73 (24-hours shift) and 49.97 ± 0.67 (fixed night shift), which were significantly longer than day workers. To prevent health consequences of night work, many countries regulate the working hours of night work not to exceed 7–9 hours a day. However, Korea does not regulate working hours for night work, and some occupations may work more hours than the prescribed overtime hours. To prevent health consequences and reduce working hours for Korean night shift workers, it is necessary to regulate the working hours of night shift workers by law.
In modern society, many people perform night work for public safety and health services or for economic reasons. When an individual works at night, the circadian rhythm is disrupted, which increases the risk of fatigue, accidents, sleep disturbances, cardiovascular disease, depression, gastrointestinal disorders, and various cancers.1,2,3,4,5
Korea had the second longest annual working hours among OECD countries in 2008: Korea’s annual working hours were 2,228 hours, 440 hours longer than the OECD average (1,788 hours). Since then, Korea’s working hours continued to decrease, but in 2021, annual working hours were 1,915 hours, still 199 hours longer than the OECD average (1,716 hours).6 Korean workers work long hours even at night: some work 24 hours a day including night work, and some work from 6:00 p.m. to 9:00 a.m. the next morning. The long working hours of night workers is one of the factors that increase working hours in Korea.
This paper reviewed the situation of the night shift work and working hours in Korea and the regulations of night shift work in various countries.
There are various types of shift work in Korea: rotating shift, 24-hour shift, day-night shift, fixed night work, and so on. The details of each shift work are described.
Many manufacturing plant workers and hospital nurses practice rotating shifts. They perform three rotating shifts (morning, evening, and night shift) with four or five teams, and usually work about 6 night shifts a month. Their working hours of night shift is usually 8 hours a day, which is not longer than the legal working hours, but in some manufacturing industries or hospitals, night shift hours are as long as 10 hours.
Twenty-four-hour shift is a type of shift in which two or three teams work alternately for 24 hours. Security guards or security workers in apartments or buildings usually perform this type of shift work. They work 24 hours a day and take one or two off-duty days. They are given 4–6 hours for sleep during night on duty, but when an unusual situation occurs, they have to wake up to deal with it. The weekly working hours are 84 hours (56 hours considering sleep and rest time as 8 hours a day, which is still long).
Some manufacturing workers, taxi drivers, and hospital caregivers perform day-night shift work. They work either a 12-hour day shift and a 12-hour night shift, or an 8–9 hour day shift and a 15–16 hour night shift. For example, care workers in the hospital work two day shifts, two night shifts, and two days off: the day shift is from 8:00 a.m. to 6:00 p.m., and the night shift is from 6:00 p.m. to 8:00 a.m. the next day. The weekly working hours are 56–60 hours (49–55 hours considering rest time).
Some workplaces, including hospitals, have workers dedicated to night shifts only. In these workplaces, full-time workers alternate night shifts every few months, or temporary workers perform fixed night shifts to reduce night work of regular workers. fixed night workers usually work 15 days a month, from 5:00 p.m. to 8:00 a.m. the next day. The working hours of them are 15 hours a day and 52.5 hours a week.
Public officers who need shift work, such as police officers, firefighters, and correctional officers, are divided into 3 or 4 groups to perform shift work. Police officers usually work a day shift, a night shift, and two off-duty days. Firefighters perform shift work with 3 groups with 3-, 6-, 9-, or 21-day cycles.7 Correctional officers work in a 4-cycle shift: a day shift, a night shift, an off-duty day, and an off-duty or day shift (the 4th day is day shift or off-duty day alternatively). The working hours are 8 hours of day shift and 15 hours of night shift, and weekly working hours are 40.3–56 hours. However, in case of an emergency, the actual working hours are longer, as they may work even on off-duty day.
There are many types of other shift work in Korea. Social workers in social welfare facility perform 4 times of 24-hour shifts a month, and residents in hospitals usually perform 1 or 2 times of night shifts a week. Also, many bus drivers work from morning until 12:00 or 1:00 a.m., and some bus drivers work at night.
To identify the working hours of shift workers, Korea’s national survey data were analyzed using SAS windows version 9.4 (SAS Institute, Inc., Cary, NC, USA). Data were derived from the 8th Korea National Health and Nutrition Examination Survey (KNHANES) conducted in 2019–2021 and the 6th Korean Working Condition Survey (KWCS) conducted in 2020–2021.8,9 For each data, the weekly working hours of all wage workers, day workers, and shift workers were analyzed considering the weights of each participant. The type of shift work was classified into rotating shift, 24-hour shift, fixed night shift, and others including irregular and split shift. In order to exclude short-term workers, those who worked less than 20 hours per week were excluded from the analysis.
Weekly working hours of shift workers were significantly longer than day workers (p < 0.001). Among the type of shift work, weekly working hours of 24-hours shift and fixed night shift were longest in KNHANES and KWCS, respectively (p < 0.001). These results confirm Korean shift workers have been working long hours, compared with day workers (Table 1).
In many countries, the law stipulates statutory working hours. Most countries stipulate 8 hours a day and 40 hours a week as normal working hours. However, statutory limit on maximum working hours is longer than this because overtime hours are separately stipulated.10 Many countries, except Europe, do not regulate the working hours of night shift work by law. However, in Europe and some countries, the working hours of night shift work are strictly regulated by law. The European Union recommends that normal hours of work for night workers do not exceed an average of 8 hours in any 24-hour period, and night workers with special hazards or heavy physical or mental strain should not work more than 8 hours in any period of 24 hours (directive 2003/88/EC).11
Table 2 shows the countries that regulate the working hours of night shift work by law. Most of countries are in Europe, a few in the Middle East, Americas and Africa, but none in Asia. The limit working hours of night work is different among countries. These countries limit the working hours per day or week for the night shift workers. In some cases, it may exceed the limit, but it is stipulated that it cannot exceed an average of 7–9 hours a day calculated over a certain period.12,13
According to the Labor Standard Law in Korea, work hours shall not exceed 8 hours a day and 40 hours a week and may be extended by up to 12 hours per week where an agreement is made between the parties. There are no restrictions on the working hours of night shift workers and some exceptions on working hours restriction: employers in the transportation services and health care services may work overtime in excess of 12 hours a week, and the working hours restriction does not apply to employees engaged in surveillance or intermittent work.14 As mentioned above, since there is no working hours restriction for night shift workers in Korea, many night shift workers are working long hours. In addition, many elderly workers over the age of 60 engaged in security surveillance work in apartments or buildings work over 12 hours or 24 hours a day because the working hours restriction does not apply to surveillance or intermittent work.
Night shift work causes disturbances in the circadian rhythm and increase the risk of many health consequences. To prevent health consequences caused by night shift work, many countries regulate the working hours of night work. However, Korea does not regulate working hours for night work, and some occupations may work more hours than the prescribed overtime hours. When workers are exposed to shiftwork and long working hours, adverse health outcomes of shiftwork can be intensified by long working hours. Considering the adverse effect of combined exposures of shift work and long working hours, more strict regulation on long working hours should be needed for shift workers. Therefore, to prevent health consequences and reduce night working hours for Korean night shift workers, it is necessary to regulate the working hours of night shift workers.
SUPPLEMENTARY MATERIAL
- 1. Boivin DB, Boudreau P, Kosmadopoulos A. Disturbance of the circadian system in shift work and its health impact. J Biol Rhythms 2022;37(1):3–28. 34969316.ArticlePubMedPMCPDF
- 2. Torquati L, Mielke GI, Brown WJ, Burton NW, Kolbe-Alexander TL. Shift work and poor mental health: a meta-analysis of longitudinal studies. Am J Public Health 2019;109(11):e13–e20.ArticlePubMedPMC
- 3. Manouchehri E, Taghipour A, Ghavami V, Ebadi A, Homaei F, Latifnejad Roudsari R. Night-shift work duration and breast cancer risk: an updated systematic review and meta-analysis. BMC Womens Health 2021;21(1):89. 33653334.ArticlePubMedPMCPDF
- 4. Voigt RM, Forsyth CB, Keshavarzian A. Circadian rhythms: a regulator of gastrointestinal health and dysfunction. Expert Rev Gastroenterol Hepatol 2019;13(5):411–424. 30874451.ArticlePubMedPMC
- 5. IARC. IARC monographs volume 124: night shift work. Accessed April 17, 2023]. https://www.iarc.who.int/news-events/iarc-monographs-volume-124-night-shift-work/ .
- 6. OECD. Hours worked. Accessed April 17, 2023]. https://data.oecd.org/emp/hours-worked.htm .
- 7. Oh HJ, Sim CS, Jang TW, Ahn YS, Jeong KS. Association between sleep quality and type of shift work in Korean firefighters. Ann Occup Environ Med 2022;34(1):e27. 36452253.ArticlePubMedPMCPDF
- 8. Korean Disease Control and Prevention Agency. Korea National Health and Nutrition Examination Survey. Accessed April 17, 2023]. https://knhanes.kdca.go.kr/knhanes/eng/index.do;jsessionid=iMOIOC07T2YqLStMmdK1ZBVntwrm4c_lWGvR4d1R.AP_name10 .
- 9. Occupational Safety and Health Research Institute. About Korean Working Conditions Survey (KWCS download). Accessed April 17, 2023]. https://oshri.kosha.or.kr/eoshri/resources/KWCSDownload.do .
- 10. OECD. Working time and its regulation in OECD countries: how much do we work and how?. Accessed April 17, 2023]. https://www.oecd-ilibrary.org/sites/c18a4378-en/index.html?itemId=/content/component/c18a4378-en .
- 11. European Union. Working hours. Accessed April 17, 2023]. https://europa.eu/youreurope/business/human-resources/working-hours-holiday-leave/working-hours/index_en.htm .
- 12. IARC. IARC monographs volume 98: Shiftwork. Accessed April 17, 2013]. https://publications.iarc.fr/_publications/media/download/2956/0a00e61a59afa99ef86b7a62f9d0024a94b5479e.pdf .
- 13. Replicon. Labor compliance, simplified. Accessed April 17, 2013]. https://www.replicon.com/compliance/ .
- 14. Korea Legislation Research Institute. Labor Standards Act. Accessed April 17, 2023]. https://elaw.klri.re.kr/kor_service/lawView.do?hseq=59932&lang=ENG .
REFERENCES
REFERENCES
Table 1
Weekly working hours of shift workers in Korea
Table 2
Working hours regulations of night workers in various countries
Figure & Data
REFERENCES
Citations
Citations to this article as recorded by 
- Association Between Types of Shift Work and Physical Health Symptoms, Including Musculoskeletal Symptoms and Sleep Disturbance: Evidence From the Seventh Korean Working Conditions Survey
Ji-Soo Jang, Sung-Kyung Kim, Sangwon Hwang, Hoon Jo, Hye-Seon Jeon
Journal of Occupational & Environmental Medicine.2026; 68(1): 34. CrossRef - Metabolic risk stratification of night shift workers in a large retail workplace through clustering and SHAP interpretation
InHo Lee, SangHee Hong, EunChul Jang, JuneHee Lee, JeongBeom Lee
Frontiers in Public Health.2026;[Epub] CrossRef - Gender differences in the association between long working hours and the onset of depressive symptoms in middle-aged and older workers in Korea: A population-based longitudinal study (2006–2022)
Seong-Uk Baek, Yu-Min Lee, Jong-Uk Won, Jin-Ha Yoon
Maturitas.2025; 193: 108175. CrossRef - Association of precarious employment with depressive symptoms and insomnia: Findings from the Korean Working Conditions Survey
Seong-Uk Baek, Jin-Ha Yoon
Journal of Psychiatric Research.2025; 181: 7. CrossRef - Association of long working hours with visceral adiposity index, anthropometric indices, and weight management behaviors: a study of Korean workers
Seong-Uk Baek, Jin-Ha Yoon
Family Practice.2025;[Epub] CrossRef - Night Shift Stress: Evaluating Heart Rate Variability as a Marker in Security Guards
Shouray Dey, A V Vinay, R Sindhu, Shishir Kumar Mahto, Sachin Kumar Patil
Indian Journal of Occupational and Environmental Medicine.2025; 29(1): 49. CrossRef - Gender discrimination in the workplace and the onset of problematic alcohol use among female wage workers: A longitudinal study in Korea
Seong-Uk Baek, Jin-Ha Yoon, Jong-Uk Won
Social Science & Medicine.2025; 379: 118183. CrossRef - A digital, real-time, history-based sleep-management tool to enhance alertness
Yun Min Song, Su Jung Choi, Dongju Lim, Reinatt Hansel Wijaya, Hyeong Jun Jang, Hea Ree Park, Eun Yeon Joo, Jae Kyoung Kim
SLEEPJ.2025;[Epub] CrossRef - Human Rights Condition of Informal Labors of South-Western Bangladesh: A Review
Avijit Mallik
Journal of Human Rights and Social Work.2025;[Epub] CrossRef - Association between shift work and brain age gap: a neuroimaging study using MRI-based brain age prediction algorithms
Youjin Kim, Joon Yul Choi, Evgeny Petrovskiy, Wanhyung Lee
Frontiers in Aging Neuroscience.2025;[Epub] CrossRef - The association of shift work and TyG index among male workers in a chemical plant of Korea: a cross-sectional study
Gwangin Baek, Yong-Jin Lee, Soon-Chan Kwon, Young-Sun Min, Jisuk Yun, Tae Jin Ahn, Eun-Chul Jang
Annals of Occupational and Environmental Medicine.2024;[Epub] CrossRef - Association between long working hours and diet quality and patterns: A latent profile analysis of a nationally representative sample of Korean workers
Seong-Uk Baek, Jong-Uk Won, Yu-Min Lee, Jin-Ha Yoon
Preventive Medicine.2024; 180: 107890. CrossRef - Investigating night shift workers’ commuting patterns using passive mobility data
Sungho Lim, Haesung Ahn, Seungchul Shin, Dongmin Lee, Yong Hoon Kim
Transportation Research Part A: Policy and Practice.2024; 181: 104002. CrossRef - Multimorbidity and its Associated Factors in Korean Shift Workers: Population-Based Cross-Sectional Study
Hye Chong Hong, Young Man Kim
JMIR Public Health and Surveillance.2024; 10: e55014. CrossRef - Sex differences in the association between social jetlag and hazardous alcohol consumption in Korean workers: A nationwide cross-sectional study
Seong-Uk Baek, Jong-Uk Won, Yu-Min Lee, Jin-Ha Yoon
Sleep Medicine.2024; 119: 549. CrossRef - The Effect of 24 h Shift Work on the Nutritional Status of Healthcare Workers: An Observational Follow-Up Study from Türkiye
Semra Navruz Varlı, Hande Mortaş
Nutrients.2024; 16(13): 2088. CrossRef - Changes in Korea’s working time policy: the need for research on flexible working hours considering socioeconomic inequality
Inah KIM
Industrial Health.2024; 62(2): 77. CrossRef - Association between precarious employment and emergence of food insecurity in Korean adults: A population-based longitudinal analysis (2008–2022)
Seong-Uk Baek, Jin-Ha Yoon
Social Science & Medicine.2024; 362: 117448. CrossRef - Special Series I: Working hours as a social determinant of workers’ health
Kyunghee Jung-Choi, Tae-Won Jang, Mo-Yeol Kang, Jungwon Kim, Eun-A Kim
Annals of Occupational and Environmental Medicine.2023;[Epub] CrossRef
Cite
XML DownloadWorking hours and the regulations for night shift workers
Working hours and the regulations for night shift workers
| Variables | 8th KNHANESa | 6th KWCSb | |||
|---|---|---|---|---|---|
| No. (%) | Mean ± SE | No. (%) | Mean ± SE | ||
| Day workers | 2,290 (86.1) | 42.83 ± 0.56 | 22,451 (88.4) | 42.50 ± 0.06 | |
| Shift workers | 369 (13.9) | 43.08 ± 0.78 | 2,935 (11.6) | 46.25 ± 0.27 | |
| Rotating shift | 94 (3.5) | 45.37 ± 0.98 | 581 (2.3) | 45.50 ± 0.54 | |
| 24-hours shift | 39 (1.1) | 57.69 ± 1.73 | |||
| Fixed night shiftc | 790 (3.1) | 50.11 ± 0.67 | |||
| Othersd | 241 (9.1) | 40.59 ± 1.00 | 1,564 (5.9) | 44.81 ± 0.36 | |
| Continent | Country | Definition of night work | Maximum length of night work |
|---|---|---|---|
| Europe | Aruba | work ≥ 4 hours between 12 a.m. and 6 a.m. | 8 hours a day |
| Bulgaria | work ≥ 3 hours between 10 p.m. and 6 a.m. | 7 hours a day, 35 hours a week | |
| Croatia | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 4 months) | |
| Czech Republic | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 26 weeks) | |
| Denmark | work ≥ 3 hours between 10 p.m. and 5 a.m. | 8 hours a day (average in 4 months) | |
| Finland | work ≥ 3 hours between 11 p.m. and 6 a.m. | 8 hours a day (in case of dangerous work) | |
| France | work ≥ 3 hours between 9 p.m. and 7 a.m. | 8 hours a day, 40 hours a week (average in 12 weeks) | |
| Germany | work ≥ 2 hours between 11 p.m. and 6 a.m. | 8 hours a day (average 4 weeks) | |
| Greece | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day | |
| Hungary | work between 10 p.m. and 6 a.m. | 8 hours a day | |
| Ireland | work ≥ 3 hours between 12 a.m. and 7 a.m. | 8 hours a day (average in 2 months) | |
| Italy | work ≥ 3 hours between 12 a.m. and 5 a.m. | 8 hours a day | |
| Liechtenstein | work between 11 p.m. and 6 a.m. | 8 hours a day (average in 1 year, maximum 12 hours) | |
| Lithuania | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 1 month) | |
| Luxembourg | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 7 days) | |
| Netherlands | work > 1 hours between 12 a.m. and 6 a.m. | 10 hours a day, 40 hours a week (average in 16 weeks) | |
| Norway | work ≥ 3 hours between 9 p.m. and 6 a.m. | 8 hours a day (average in 4 weeks) | |
| Portugal | work ≥ 3 hours between 10 p.m. and 7 a.m. | 8 hours a day | |
| Romania | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 3 months) | |
| Slovenia | work ≥ 3 hours between 11 p.m. and 6 a.m. | 8 hours a day (average in 4 months) | |
| Spain | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 15 days) | |
| Sweden | work ≥ 3 hours between 10 p.m. and 6 a.m. | 8 hours a day (average in 4 months) | |
| Switzerland | work between 11 p.m. and 6 a.m. | 9 hours a day | |
| United Kingdom | work ≥ 3 hours between 11 p.m. and 6 a.m. | 8 hours a day (average in 17 weeks) | |
| Meddle East | Israel | work ≥ 2 hours between 10 p.m. and 6 a.m. | 7 hours a day, 58 hours a week |
| North America | Mexico | work between 8 p.m. and 6 a.m. | 7 hours a day, 42 hours a week |
| South America | Argentina | work between 9 p.m. and 6 a.m. | 7 hours a day |
| Venezuela | work between 7 p.m. and 5 a.m. | 7 hours a day, 35 hours a week | |
| Central America | Costa-rica | work between 7 p.m. and 5 a.m. | 6 hours a day, 36 hours a week |
| Guatemala | work between 6 p.m. and 6 a.m. | 6 hours a day, 36 hours a week | |
| Honduras | work ≥ 3 hours between 7 p.m. and 5 a.m. | 6 hours a day, 36 hours a week | |
| Panama | work between 6 p.m. and 6 a.m. | 7 hours a day, 42 hours a week | |
| Africa | Angola | work ≥ 3 hours between 8 p.m. and 6 a.m. | 10 hours a day |
| Kenya | (not defined) | 60 hours a week, 144 hours in 2 weeks |
Table 1 Weekly working hours of shift workers in Korea
The data are shown as frequency (%) or mean ± SE.
SE: standard error.
aKorea National Health and Nutrition Examination Survey (2019–2021); bKorean Working Conditions Survey (2020–2021); cIncluding 24-hour shift; dIrregular, split shift, and so on.
Table 2 Working hours regulations of night workers in various countries
Korean version of this article is available with the Online-only Data Supplement (Download PDF).
