Long Working Hours and Unhealthy Lifestyles of Workers: A Protocol for a Scoping Review

Abstract

Poor lifestyle behaviors, including unhealthy dietary habits, lack of physical activity, smoking, inadequate and poor-quality sleep, and alcohol consumption, are well-documented risk factors for health deterioration. Previous studies have suggested that such undesirable lifestyle behaviors may mediate the effects of long working hours on negative health outcomes. This protocol paper aims to introduce and outline the methods for this scoping review. The proposed scoping review will map the existing research on the relationship between working hours and lifestyle behaviors, identifying areas and gaps in the evidence that warrant further investigation. This review will include only peer-reviewed, published articles written in English. All studies examining the relationship or effects of working hours on the five a priori defined major lifestyle components will be considered (diet, physical activity, tobacco use, sleep, and alcohol use), without restrictions on region, publication year, or study design. This review will be performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines. The databases will include MEDLINE, EMBASE, CINAHL, and PsycINFO. The search equation will be structured to include the topic of working hours while also encompassing at least one of the five lifestyle topics: physical activity, diet, sleep, tobacco use, and alcohol consumption. Two reviewers will screen the articles and extract pertinent data. This investigation will primarily focus on evaluating the existing evidence and identifying any gaps in understanding the relationship between working hours and each lifestyle component. A narrative summary will be presented to explain the findings of the included studies.

1. Introduction

The health implications of long working hours are important public health concerns. Approximately 488 million people worldwide experienced long working hours (≥55 h/week), resulting in over 745,000 annual deaths from cardiovascular diseases in 2016 [1]. “Karoshi”, which means “death from overwork”, has sparked debates on working hour regulations, particularly in several Western-Pacific countries, such as Japan and Korea, where long working hours are most prevalent [2]. In Korea, approximately 6% of wage workers worked more than 52 h per week in 2020, with higher proportions observed among men, blue-collar workers, and employees in small businesses with fewer than five workers [3,4]. Numerous adverse health consequences have been found to be associated with long working hours, including circulatory diseases, stroke, and depressive symptoms [5,6,7,8]. Notably, previous research has consistently demonstrated a relationship between long work hours and the onset of cardiovascular diseases [9,10,11,12].

Lifestyle is constituted by multidimensional components that encompass various factors, including sleep, smoking, alcohol use, physical activity, and diet. A number of meta-analyses have consistently confirmed that lifestyle behaviors are closely related to all-cause or cardiovascular mortality [13,14,15,16]. Therefore, healthy lifestyle behaviors are the foundation of good health, and their promotion is essential for public health policies. Recently, the American Heart Association proposed the concept of “Life’s Essential 8” to promote healthy lifestyles and reduce the health burdens associated with poor health behaviors. The health behavior factors of Life’s Essential 8 include physical activity/exercise, nutrition/diet, tobacco use, and sleep [17]. In addition to such lifestyle behaviors, alcohol consumption has also been considered an important health behavior in the literature, particularly in relation to working hours and physical or mental health disorders [18,19]. These health behaviors can interact synergistically to affect health outcomes, including cardiovascular disease and mortality [20,21]. This is particularly relevant since individuals with unhealthy behaviors often have a constellation of risk factors that amplify their overall health risk.

In the current theoretical perspective, unhealthy lifestyle behaviors are believed to be one of the major mechanisms by which exposure to long working hours leads to negative health outcomes, including ischemic heart diseases, stroke, and mental health problems [1,7,22,23]. Previous research has demonstrated that long working hours can significantly contribute to the development of unhealthy lifestyles among workers. These adverse effects include an increased likelihood of engaging in behaviors such as poor diet [24], cigarette smoking [25], physical inactivity [26], inadequate sleep [27], and excessive alcohol consumption [18]. Long working hours have been related to an elevated level of work-related stress and a concomitant decrease in leisure time, thus making employees more susceptible to engaging in risky substance abuse [18] and experiencing a decline in both physical activity and sufficient rest [26].

There has been growing academic interest in unhealthy lifestyle behaviors and potential barriers for them. Indeed, previous systemic reviews have explored how individual components of lifestyle behaviors are associated with working hours (e.g., risky alcohol use) [28]. However, no published or ongoing systematic or scoping reviews that incorporate the multidimensional components of lifestyle have been identified through an initial search of PROSPERO, PubMed, and JBI Evidence Synthesis. Consequently, it is imperative to conduct a scoping review of the existing literature on the association between long working hours and lifestyle behaviors. This review will identify potential research gaps and provide valuable insights into lifestyle factors that warrant further investigation. The conceptual framework for the association between long working hours, lifestyle behavior, and health outcomes is presented in Figure 1. The findings of the review will also be relevant to policymakers who are developing strategies to promote health behaviors in the workforce. This scoping review is expected to serve as a significant foundational step towards conducting a more focused and systematic review of specific lifestyle factors in the future.

The objective of this scoping review is to (i) map out the state of the existing studies on the relationship between long working hours and the five lifestyle behaviors and (ii) identify areas and gaps in knowledge that warrant further investigations. Ultimately, by elucidating these connections and knowledge gaps, this review will underscore the development of evidence-based policies aimed at fostering work–life balance and reducing the detrimental health consequences associated with long working hours.

2. Materials and Methods

This study will adapt the scoping review framework outlined by the work by Arksey and O’Malley (2005) [29]. Scoping review studies explore broader themes and subject areas, accommodating a wider range of research methodologies, which align with the objective of our study. This review will conduct this scoping review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guideline [30]. The review question is as follows: “What is known from the current literature about the relationships between long working hours and lifestyle behaviors?”

2.1. Eligibility Criteria

This study will follow the Population/Concept/Context (PCC) framework to describe the eligibility criteria. This study will include peer-reviewed qualitative, quantitative, or mixed methods studies written in English. Secondary studies, such as systematic reviews, and the gray literature will be excluded. The primary objective of this review is to provide an overview of the current evidence pertaining to working hours and their potential impact on lifestyle behaviors, based on peer-reviewed published studies.

2.1.1. Participants

The study population will include working-age individuals aged 15 and above, encompassing both formal and informal economy workers. However, individuals below the age of 15 and unpaid family workers (unpaid domestic workers) will be excluded from the study.

2.1.2. Concept

This scoping review will aim to identify and summarize the current literature on the potential effects of long working hours on lifestyle behaviors, covering the following a priori defined components of lifestyles: physical activity/exercise, nutrition/diet, tobacco use, sleep, and alcohol use. This study will include studies that examine whether working hours are associated with at least one of the five lifestyle components. However, other atypical work time arrangements, such as evening work, night work, shift work, weekend work, on-call work, non-fixed (variable) working hours, or work from home, will not be considered in this review.

2.1.3. Context

Studies from all countries and regions will be included. This review will not be restricted to specific genders, occupations, or industrial sectors.

2.2. Search Strategy

This study will follow the 3-step approach for this review. Initially, the authors conducted a preliminary search of MEDLINE (PubMed), Embase, Scopus, and CINAHL on 1 September 2024 to identify articles related to the topic. Subsequently, a comprehensive search strategy was developed for PubMed using the titles, abstracts, and keywords of articles. The detailed search equation is outlined in

Table 1. Search equation (search date: 1 October 2024).

Search Set	Search	Search Details	Results
Working hour	#1	“Work Schedule Tolerance” [Mesh] OR workhour*[tiab] OR “working hour*”[tiab] OR “overtime*”[tiab] OR work time*[tiab] OR “overwork*”[tiab] OR “extended hour*”[tiab] OR “extended work*”[tiab] OR “work hour*”[tiab] OR “worktime*”[tiab] OR “long hour*”[tiab] OR working hour* [tiab] OR workhour* [tiab] OR “hours of work*”[tiab] OR “hours worked”[tiab]	28,391
Physical activity/exercise	#2	“Exercise”[Mesh] OR (physical[tiab] AND activit*[tiab]) OR (physical[tiab] AND inactivit*[tiab]) OR “exercise*”[tiab] OR fitness[tiab] OR sport*[tiab] OR aerobic*[tiab] OR “physical exercise”[tiab] OR workout*[tiab]	918,344
Nutrition/diet	#3	“Diet, Food, and Nutrition” [Mesh] OR “diet, healthy”[Mesh Terms] OR “Diet”[MeSH Terms] OR diet*[tiab] OR nutrition*[tiab] OR food[tiab] OR food intake[tiab] OR (food[tiab] AND consumption*[tiab]) OR eat[tiab] OR appetite[tiab] OR feeding*[tiab] OR “Mediterranean diet”[tiab] OR (eating*[tiab] AND habit*[tiab]) OR (diet*[tiab] AND pattern*[tiab]) OR meal*[tiab] OR intake*[tiab]	2,413,386
Tobacco use	#4	“Smokers”[Mesh] OR “Smoking”[Mesh] OR “Tobacco Use”[Mesh] OR “Tobacco Use Disorder”[Mesh] OR smoke[tiab] OR smoker*[tiab] OR smoking*[tiab] OR tobacco[tiab] OR cigarette*[tiab] OR sigarette*[tiab] OR nicotine*[tiab]	474,260
Sleep	#5	Sleep*[tiab] OR insomnia*[tiab] OR asleep*[tiab] OR awakening[tiab] OR circadian[tiab]	326,499
Alcohol	#6	“Alcohol Drinking”[Mesh] OR “alcohol*”[tiab] OR “wine”[tiab] OR “beer”[tiab] OR “liquor”[tiab] OR “spirit”[tiab] OR “alcoholism*”[tiab] OR “substance*”[tiab] OR “drink*”[tiab] OR (heavy[tiab] AND drink*[tiab]) OR (alcohol[tiab] AND depend*[tiab]) OR (alcohol [tiab] AND consumption*[tiab]) OR “alcoholic*”[tiab] OR (alcohol[tiab] AND abuse*[tiab]) OR (drink*[tiab] AND behavior*[tiab]) OR (alcohol[tiab] AND misuse*[tiab])	938,466
Other keywords	#7	“Health Behavior”[Mesh] OR “Health Risk Behaviors”[Mesh] OR “Lifestyle”[tiab] OR “health-related behavior*”[tiab] OR (life[tiab] AND style*[tiab]) OR (health[tiab] AND behavior*[tiab])	695,773
Concept: lifestyles	#8	#2 OR #3 OR #4 OR #5 OR #6 OR #7	4,913,370
Final	#10	#1 AND #8	9065

The asterisks (*) are used for truncation.

. This search equation will be applied to information sources. This combination will be applied to each database while keeping the search terms unchanged. In addition, a manual screening of the reference lists of all included articles will be conducted to identify further eligible studies. Only studies written in English will be included. To ensure the inclusion of all relevant sources, no date restrictions will be imposed. The following databases will be searched: MEDLINE (PubMed), EMBASE, CINAHL (EBSCOhost), and PsycINFO (Ovid).

2.3. Study Selection

All identified citations will be collected and organized using Endnote v.21 (Clarivate Analytics, Philadelphia, PA, USA). Duplicate citations will be removed, and titles and abstracts will be screened by two independent reviewers to ensure they meet the inclusion criteria. The full text of selected citations will then undergo a thorough review by two independent reviewers. Specifically, this review will include only peer-reviewed articles that fully meet the predetermined criteria of the PCC framework. Studies that do not meet the eligibility criteria at the full-text review stage will be excluded, with reasons for exclusion stated to ensure transparency. In case of disagreements, they will be resolved through discussion between two reviewers or with the involvement of a third reviewer. The complete search results and inclusion process will be detailed in the final scoping review. It will be displayed in a diagram based on the PRISMA-ScR guidelines. The diagram will follow the format proposed by the updated guideline for systematic reviews, 2020 [31] (Figure 2).

2.4. Data Extraction

Data will be extracted from each article based on the extraction tool developed by the research team (

Table 2. Data extraction instrument.

Main Category	Subcategory	Description
1. Authors		Name of the authors
2. Title		-
3. Journal		Published journal
4. Publication year		-
5. Origin (country)		The region where the study was conducted
6. Study design	Type Design	(i) Type of study (e.g., original research, review) (ii) Study design (e.g., qualitative study, cross-sectional, cohort)
7. Population	Sample Size Characteristics	(i) Number of participants, mean follow-up period (ii) Characteristics of the sample (e.g., gender, age, occupation, industrial sector)
8. Working hours	Categorization Measurement	(i) Categorization of working hours (ii) Measurement of working hours (e.g., self-reported, objectively measured)
9. Lifestyle behaviors	Component Measurement	(i) Component of lifestyle behaviors (ii) Measurement of lifestyle behaviors
10. Key findings		Narrative descriptions of the summary of the main findings

). Authors, titles, journals, publication years, origins/regions of study, sample sizes, characteristics of participants (e.g., gender, age), study designs, categorizations of working hours, lifestyle outcomes, and key findings will all be extracted. To ensure consistency in the extraction process, two independent reviewers will initially test the data extraction tool on the first five following the method described by Pollock et al. [32].

2.5. Data Analysis and Presentation

The extracted data from included full-text articles will be presented in diagrams and tables that are aligned with the research objectives. The anticipated results will include the first author, publication year, study region, sample size, participant characteristics, study design, working hour categories, lifestyle outcomes, key findings, and limitations/biases. Although the first author and publication year are not results in themselves, they are essential information for organizing the papers. Therefore, we have included them in the extracted information. The tabulated findings will be accompanied by a narrative summary that explains how the results relate to the research question and objectives. The purpose of this scoping review is to explore the basic characteristics of the existing literature and identify gaps, rather than to critically appraise the literature. Therefore, a risk-of-bias assessment was not conducted. This decision aligns with the PRISMA guidelines, which consider risk-of-bias assessment optional for scoping reviews [30].

3. Discussion

Long working hours are recognized as a major occupational risk factor that can have various adverse impacts on workers’ health. Research indicates that extended working hours can lead to physical and mental health issues, particularly an increased risk of cardiovascular diseases such as stroke and ischemic heart diseases [1,7,8,22,33]. Long working hours can make it challenging for workers to maintain healthy lifestyle habits, often leading to irregular eating patterns, insufficient physical activity, and sleep disturbances [24,26,27,34]. Furthermore, the high stress associated with long working hours can prompt workers to engage in alcohol consumption or tobacco use as coping mechanisms for their stress [18,25]. Considering that these lifestyle factors are significant predictors of cardiovascular diseases and mental disorders [35], understanding the association of long working hours with health behaviors is essential for developing appropriate interventions. However, the current literature provides evidence of individual associations between work hours and health behaviors, indicating the need for a comprehensive summary to guide future research endeavors.

The proposed scoping review aims to review and synthesize existing research on the association of working hours with workers’ health behaviors. To our knowledge, this is the first comprehensive review to specifically examine the association between long work hours and various lifestyle factors. While this review will provide a deeper understanding of this topic, it is important to note that limitations such as language restrictions and the exclusion of unpublished studies may affect the generalizability of the findings. Additionally, the scope of this review is limited to five specific lifestyle behaviors, and there may be other relevant factors, such as screen time, social interaction, and stress management, that were not included. Lastly, as a scoping review, this study cannot quantitatively assess the relationship between individual lifestyle behaviors and long working hours. These limitations can be considered in future scoping reviews or systematic meta-analyses. By systematically examining and summarizing previous studies on the impact of long working hours on employees’ lifestyles, this research seeks to explore the relationship between these two variables. The findings of this scoping review will serve as a foundation for future research endeavors and provide valuable insights for workers, epidemiologists, and policymakers. Furthermore, this review will provide workplaces with comprehensive insights into how long working hours can adversely affect employees’ lifestyle behaviors, thereby enabling the development of evidence-based organizational policies to promote work–life balance.

4. Conclusions

This scoping review aims to serve as a foundational resource for mapping the evidence pertaining to the association between long working hours and the lifestyles of workers. This review will contribute to promoting healthy lifestyle behaviors among workers and provide guidance for future research aimed at elucidating the complex association between working hours, lifestyles, and worker health.