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Abstract

Although seafaring is one of the most important professions for trade in goods in the 21st century, the results of recent research indicate that seafarers face various sources of stress in their work, including high workload and long working hours. These stressors can be reflected in low job satisfaction and poor mental health, which can result in sleep problems, and consequently lead to various somatic symptoms. The main goal of this mixed method research was, therefore, to expand knowledge about seafarers’ sleep on board, whereby a sequential explanatory design was used. Study 1 (N = 286 male seafarers from Croatia) examined whether the number of sleep hours on board has a mediating role in explaining the relationship between job satisfaction and mental health as predictors of somatic symptoms. The results of the path analysis showed that higher job satisfaction directly and indirectly through longer sleep on board reduces the number of somatic symptoms, while better mental health directly contributes to fewer somatic symptoms. Study 2 (N = 205 seafarers from Croatia) aimed to get a deeper insight into the sleep of seafarers on board, whereby 39% (N = 80) of the participants had difficulties related to sleep problems on board. The thematic analysis of their answers (N = 76) showed the sleeping difficulties experienced by seafarers on board and gave an insight into the consequences of sleeping difficulties and the coping strategies they use. The results of this research indicate the importance of developing healthy work environments for seafarers.

Keywords

seafaring sleep on board mental health job satisfaction somatic symptoms mixed methodology

What do we already know about this topic?

Seafarers present a vulnerable group considering mental and physical health due to a highly demanding and stressful profession, and there is a large body of studies examining fatigue, but research focusing on the relationship on sleep on board and somatization is scarce.

How does your research contribute to the field?

This mixed-method study tests the mediating role of the quantity of sleep on board between the hypothesized antecedents of somatic symptoms (job satisfaction and mental health) and somatic symptoms, as well as gives a deeper insight into the nature of on board sleep difficulties.

What are your research’s implications toward theory, practice, or policy?

This study gives insight into the relationship between sleep on board and somatization, which needs to be re-examined in the methodologically more robust research, and offers practical guidelines about the importance of on board working conditions that support health.

Introduction

Seamanship is a profession that can be defined as the “skill in managing a ship”¹ or “the art of operating a vessel.”² It is one of the oldest professions; throughout history, it was sailors who were the first to discover new continents and expand their horizons. Still, nowadays, seafaring is one of the most important professions for trade in goods. It is no surprise that over 80% of world trade occurs by sea.³ There are approximately 1.89 million seafarers worldwide, and almost all seafarers are male (98%). This occupation is marked by various work stressors, such as high workload and long working hours, low levels of control over work, lack of support received from colleagues and companies, bad social relationships at work, and job insecurity. These stressors often lead to typical stress symptoms such as insomnia, loss of concentration, anxiety, frustration, anger, headaches, coronary diseases, and lower work productivity, and they can also lead to burnout.⁴ Pronounced onboard stressors include long working hours, precisely 67 to 80 working hours per week⁵ and conflicting roles⁶, which lead to accumulation of fatigue—one of the maritime industry’s biggest problems.

Fatigue is a consequence of work stress, high work demands, insufficient number of workers, long working hours, insufficient rest due to the monitoring system, disturbed circadian rhythm, sleep deprivation, and compromised safety standards.^7-14 The connection between energy depletion and fatigue led to the accepted assumption that fatigue is the effect of long and continuous work, but nowadays, this assumption is considered too simplistic. In response, Hockey¹⁵ states that the need to maintain high levels of effort at low levels of controllability is the underlying cause of fatigue. Fatigue, therefore, depends not only on the high workload but also on the effort invested in responding to these demands. The relationship between fatigue and work is moderated by controllability, which means the subjective feeling of controlling work tasks, and controllability can reduce the negative consequences of high workload.¹⁵ Although many studies^{10,13,14,16,17} have investigated seafarers’ fatigue and the impact of fatigue on their health and well-being, Allen et al⁷ note that fatigue is more common than researchers can currently capture with commonly used measures, such as self-reports. At the same time, due to the reduced number of crew, Smith et al¹⁷ warn of an increase in insufficiently recorded working hours among seafarers. Due to shift work, especially night shifts, a disturbed circadian rhythm is one of the most important factors in the development of sleep disorders, but also other serious diseases, such as gastrointestinal problems and cardiovascular diseases.¹⁸ In research conducted in the last decade, it was determined that long-term fatigue is associated with physical and mental health outcomes, and fatigue is also associated with performance at the workplace, the risk of accidents on board, and long-term well-being.^13,14,17

Baumler¹⁹ reports that in the past 100 years, the number of working hours per week of seafarers has increased by almost 50%. It can be assumed that because of this, seafarers have difficulties with the quality of sleep, but also with the amount of sleep, which according to research should be an average of 7 h for adults.²⁰ Recent mixed methods study²¹ indicated on sleeping problems as one of the essential threat to psychological well-being on-board. According to this study, on-board sleeping problems arise directly from working environment and working conditions. Bailey²² points out the importance of managing fatigue and sleep quality while giving seafarers useful advice on how to deal with sleep problems on board.

Sleep debt²³ is a term that defines a constant lack of sufficient amount of sleep, and presents a threat to seafarers’ health and safety, considering the characteristics of the seafaring profession.²⁴ A meta-analysis²⁵ indicates that lack of sleep is the cause of various mental health problems, like depression, anxiety, rumination, stress, and symptoms of psychosis. According to the research of Grossi et al,²⁶ sleep quality, but not sleep quantity, was a significant predictor of both well-being and burnout. Given that this paper deals with seafarers’ sleep and some possible antecedents and outcomes of seafarers’ sleep, the constructs used in this research and their relationships are presented in the following text. Somatization implies the tendency to experience and express psychological stress through somatic or physical symptoms that do not have a clear organic or physiological explanation²⁷ and the most frequent somatic symptoms are cardiovascular, gastrointestinal, musculoskeletal pain and fatigue.²⁸ Somatic symptoms and sleep difficulties are often associated with acute sources of stress, especially in highly demanding work environments.²⁹ Considering the amount of workload, both mental and physical, Tang et al³⁰ investigated the relationship between chronic back pain and insomnia, and the results indicated that patients with chronic pain more often showed symptoms of clinical insomnia, with the best predictors of insomnia being affective pain ratings and health anxiety. Chronic neck pain is also one of the problems that many workers face,³¹ and the prevalence of sleep problems in people with chronic back and neck pain who take analgesics is about 42%, while 20% of patients with these types of pain report that they sleep less than 4 h on average during night.³² Mohr et al³³ reported that sleep partially mediates the relationship between somatic symptoms and traumatic stress symptoms, while Challa et al³⁴ described sleep quality as a mechanism underlying the relationship between posttraumatic stress symptoms and somatic symptoms. Moreover, Gandhi et al³⁵ found that somatic symptoms and job satisfaction are negatively correlated in a sample of nurses from India.

Job satisfaction is a concept that is often researched in the work environment, and it can be defined as a worker’s assessment of his own experience at work or the extent to which an individual likes his job.³⁶ Reducing the time spent in ports due to more efficient cargo handling operations,³⁷ and the increasing competitiveness of jobs on land due to better wages and working conditions can affect seafarers’ job satisfaction.³⁸ Even though there is no research on the relationship between quality or quantity of sleep and job satisfaction among seafarers, research on some other samples of workers indicate a positive relationship between these 2 constructs,³⁹ and it can be assumed that a similar relationship would exist among seafarers. As the human factor is most often the leading cause of maritime accidents, Hystad et al¹⁶ found in seafarers that fatigue and poor sleep quality are positively related, as expected, but what is worrying is the fact that the sleep problems mentioned so far among seafarers do not only affect themselves but also the safety of the ship. Thus, in the same study, the authors found a positive relationship between the risk of an accident and the poor quality of sleep, as well as fatigue. Other findings on job satisfaction among seafarers emphasize a variety of positive high job satisfaction outcomes, including lower intention to leave the job,⁴⁰ better performance,^36,41 lower burnout⁴² and higher motivation to follow safety procedures,⁴⁰ which may be in positive relationship with mental health.⁴³

Mental health, according to WHO⁴⁴ is “a state of mental well-being that enables people to cope with the stresses of life, realize their abilities, learn well and work well, and contribute to their community”. Nowadays, health is no longer defined only through the absence of disease, but as it can be seen from the definition of mental health, it is defined by the well-being of the organism. Furthermore, studies which focused on the relationship between somatization and mental health⁴⁵ conclude that depression is positively associated with the number and frequency of somatic symptoms.

Aim, Research Problems, and Hypotheses

Considering the importance of sleep shown by previous research, this study aims to expand the literature on seafarers’ sleeping on board. Review of the literature showed that facing with occupational stressors in the seafaring may be reflected in job dissatisfaction and impaired mental health, which can result in sleep problems, and consequently lead to somatization. We focused on 2 research problems, whereby the first one was to investigate the mediating role of the quantity of sleep on board between the hypothesized antecedents of somatic symptoms (job satisfaction and mental health) and somatic symptoms. According to previous research in a sample of nurses³⁵ and office workers⁴⁶ it was hypothesized that higher job satisfaction level would directly contribute to lower levels of somatic symptoms. Moreover, it was expected that better mental health would contribute to lower levels of somatic symptoms, which is in line with findings on military personnel⁴⁷ and university employees.⁴⁸ Finally, according to Xie et al³⁹ and Challa et al³⁴ it was expected that on-board sleeping would mediate a relationship between job satisfaction and mental health as predictor variables and somatic symptoms. The second research problem was to gain a deeper insight into the experience of sleeping on a ship, that is the quality of seafarers’ sleep during their stay on board focusing on the personal experience of sleep difficulties.

Methods

Here presented research is a mixed-method study implementing the sequential explanatory design⁴⁹ to expand knowledge on seafarers’ sleep in on-board environment. To gain a deeper insight into seafarers’ sleep problems and to clarify the results from the quantitative study (Study 1) further, a qualitative study (Study 2) was conducted.

Procedure

The quantitative study (Study 1) was conducted in paper-pencil, and online form from April until July 2019. The qualitative study (Study 2) was conducted from March to May 2021 in the online form.

A written informed consent was obtained before filling in the questionnaire in both studies. Participants could contact principal researchers in both studies if they had questions, comments about studies and/or wanted feedback about the results.

Study 1

The convenient sample consisted of 286 Croatian male seafarers. Their age ranged from 18 to 65 years (M = 37.40 years, SD = 10.28 years), and their mean job experience in seafaring was 12.5 years (SD = 9.82 years). Most participants (89.4%) reported working in international shipping and for an international seafaring organization (80.2%). Considering ship type, 60.7% of our sample worked on cargo ships, 20.4% of the sample worked on passenger ships, 13.7% of the sample worked on special purpose ships, while the rest of the sample worked in other work environments such as oil platforms. There were a variety of working positions reported by the participants: captains (12.2%), chief engineers (6.6%), deck officers (33.6%), engine officers (21%), electricians (4.2%), deck crew members (4.9%), engine crew members (2.2%), and cadets (10.8%).

Participants completed following measures: the socio-demographic questionnaire, the Job Satisfaction Scale,⁵⁰ the Mental Health Inventory (MHI-5),⁵¹ the Patient Health Questionnaire − 15 (PHQ-15),²⁸ and they were asked how many hours in a typical day they spend sleeping while on board. The Job Satisfaction Scale⁵⁰ contains 5 items (eg, Most days I am enthusiastic about my work; I find real enjoyment in my work) and measures an individual’s general attitude toward his work. The Mental Health Inventory⁵¹ is a part of the Short Form Health Survey (SF-36),⁵² and measures general mental health in the domains of anxiety (How much of the time have you been a very nervous person), depression (How much of the time have you felt downhearted and blue?), general positive affect (How much of the time were you a happy person; How much of the time have you felt calm and peaceful?), and behavioral/emotional control (How much of the time have you felt so down in the dumps that nothing could cheer you up?). The Patient Health Questionnaire − 15 (PHQ-15)²⁸ is comprised of 15 items measuring the most frequent somatic symptoms (eg, cardiopulmonary, gastrointestinal, fatigue-related symptoms, and pain in different body parts). Considering that all participants were males, the item measuring problems with period was omitted from the analyses.

All of the used measures showed good reliability (Table 1).

Table 1.

Descriptive Parameters and Correlation Matrix of the Observed Variables (N = 286).

Variable	1.	2.	3.	M	SD	Min	Max	α
1. Job satisfaction	1			23.73	6.14	5.00	35.00	.80
2. Mental health	.365**	1		23.04	4.23	5.00	30.00	.76
3. Sleeping on board (h)	.169**	.122*	1	6.81	1.14	3.00	12.00	–
4. Somatic symptoms	–.286**	–.354**	–.178**	3.95	3.20	0.00	17.12	.82

P < .05. **P < .01.

Study 2

In Study 2, after completing socio-demographic questionnaire, participants were asked if they had problems with sleep on board and to describe the difficulties, when they usually happen, how their everyday functioning is affected, and how they cope with them.

Two hundred five participants completed the questionnaire, and 80 participants answered they had problems with sleep on board. Out of 80 participants who had sleep problems on board, 76 participants (7 female) answered an open-ended question about sleeping difficulties on board. This study’s age range was from 21 to 59 years (M = 35.55 years, SD = 10.50 years), and the mean job experience was 11.41 years (SD = 9.70 years). Most of the participants worked on cargo ships (61.84%), followed by the passenger (19.74%) and special purpose ships (15.79%), while the rest of the participants reported working in other work environments. Similarly to Study One, a wide range of job positions was reported by the participants: captains (2.63%), chief engineers (7.89%), deck officers (48.68%), engine officers (18.42%), electricians (1.32%), engine crew members (3.95%), deck crew members (1.32%), steward department members (3.95%), cadets (9.21%), and others (2.63%).

Data Analyses

Data from the Study 1 was analyzed using IBM SPSS and IBM SPSS AMOS. Descriptive parameters and Pearson correlation coefficients between the observed variables were computed before path analysis. The following parameters were used to analyze the proposed model fit: ratio between χ² and degrees of freedom, Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), Standardized Root Mean Square Residual (SRMR), and Root Mean Square Error of Approximation (RMSEA). The acceptable values of model fit are: χ²/df < 3, CFI i TLI > 0.90 te RMSEA i SRMR < 0.10, while following values suggest good fit: χ²/df < 3, CFI i TLI > 0.95, RMSEA < 0.06, and SRMR < .08.⁵³

Answers to open-ended questions in Study 2 were analyzed using post-positivism as an epistemological basis. Post-positivism assumes objective reality but considers the subjectivity of reality.⁵⁴ This implies that the qualitative data was approached inductively, and themes emerged from the data using thematic analysis.⁵⁵ In the first step of thematic analysis, 2 researchers familiarized themselves with the data by reading participants’ responses and writing initial ideas. In the second step, codes were generated for the whole dataset, and in the third step, codes were organized in the themes by the same 2 researchers. The third researcher helped with reviewing themes as well as defining and naming themes in the final step of the analysis.

Results

Study 1

Table 1 shows descriptive parameters and correlation matrix of the observed variables.

Job satisfaction was positively correlated with mental health and sleeping on board, while it was negatively correlated with somatic symptoms. Mental health was positively correlated with sleeping on board, and somatic symptoms were negatively correlated with both mental health and sleeping on board.

The results of path analysis for job satisfaction and mental health as predictor variables, sleep on board as a mediator and somatic symptoms as a criterion variable are shown in Table 2 and Figure 1.

Table 2.

The Results of Path Analysis for Job Satisfaction and Mental Health as Predictor Variables, Sleep on Board as a Mediator and Somatic Symptoms as a Criterion Variable (N = 286).

Effect	ß	SE
Job satisfaction → Sleep on board	.169**	0.062
Mental health → Somatic symptoms	–.280**	0.066
Job satisfaction → Somatic symptoms	–.165**	0.061
Sleep on board → Somatic symptoms	–.116*	0.059

P < .05. **P < .01.

Figure 1.

The results of path analysis for job satisfaction and mental health as predictor variables, sleep on board as a mediator, and somatic symptoms as a criterion variable (N = 286).

Higher levels of job satisfaction directly contributed to lower levels of somatic symptoms. Moreover, higher levels of job satisfaction indirectly contributed to lower levels of somatic symptoms through longer sleep on board. Better mental health directly contributed to lower levels of somatic symptoms. It was decided to accept the proposed model since all the parameters used to evaluate the proposed model fit were good (χ²/df = 1.226; TLI = 0.986; CFI = 0.998; RMSEA = 0.028; SRMR = 0.020)

Study 2

Results of Study 2 showed that large proportion of the examined sample (39%; 80 from 205 seafarers) report difficulties related to sleep problems on board. Thematic analysis of seafarers’ answers to open-ended questions (N = 76) has shown that their answers may be categorized into 3 main themes: descriptions of sleeping difficulties; experienced consequences of sleeping difficulties and coping strategies which they use in facing with problems related to onboard sleeping. Table 3 shows the main themes with the original participants’ examples.

Table 3.

Main Themes with Original Participants’ Examples (N = 76).

Main themes	Examples of responses
Difficulties	“. . .night sleep is interrupted in shorter periods. . .”
	“I often wake up at night.”
	“Sleep periods are short.”
	“It is impossible to have a consistent sleep schedule.”
Sleep on board consequences	“. . .it is difficult to stay focused on work duties after two or three sleepless nights in a row.”
	“I feel sleepy during the day.”
	“. . .the lack of sleep affects the way I think and my mood.”
	“. . .my reaction time is slower.”
	“I sometimes have migraines.”
	“I constantly feel worn out.”
	“. . .even in the free time, I am not able to sleep.”
Coping strategies	“Whenever I have free time, I sleep.”
	“I use Melatonin to fall asleep faster.”
	“I can’t sleep after the watch, so I take anxiolytic to relax me.”
	“Chronic sleep debt requires drinking lots of coffee to awaken. However,
	coffee has a counter-effect when you want to sleep”
	“When I have time for a workout, it helps me.”
	“The easiest way is to prepare mentally, accept the situation as it is, and work.”
	“It is necessary to adapt biorhythm to be able to sleep.”

Seafarers reported a variety of difficulties concerning sleep onboard. As shown in Table 3, participants reported short sleep periods often interrupted with waking up at night, daytime sleepiness, difficulties with staying focused and inconsistent sleep schedule. According to seafarers’ reports, these difficulties lead to harsh consequences such as slower reaction time, impaired reasoning and mood instabilities. Physical health problems arise in the form of constant fatigue, migraines, and inability to fall asleep. To cope with the difficulties and consequences above, seafarers reported diverse coping strategies, including medication use, excessive coffee drinking, and physical activity. The seafarers mentioned acceptance, as well, which is a cognitive coping strategy. Generally, seafarers’ reports from this study show that sleeping difficulties arise from work overload, whereby seafarers recognize this issue as a huge threat to their physical and mental health and to onboard safety.

Discussion

This study aimed to broaden the existing body of seafarers’ sleep studies by using the sequential explanatory design.⁴⁹ More precisely, in the quantitative study (Study 1), we examined the relationship between job satisfaction, mental health, sleep on board, and somatic symptoms in a sample of Croatian seafarers, whereas, in the qualitative study (Study 2), we wanted to achieve a deeper understanding of seafarers’ sleep onboard. The results of the quantitative study are not entirely in line with the hypotheses. The longer sleep on board mediates the relationship between higher job satisfaction levels and lower somatic symptom levels, but it does not mediate the relationship between mental health and somatic symptoms. Higher job satisfaction levels, both directly and indirectly, through longer sleep on board, contribute to lower somatic symptom levels, while better mental health directly contributes to lower somatic symptom levels.

Our finding that higher job satisfaction directly contributes to lower somatic symptom levels adds to the existing body of literature on the importance of job satisfaction among seafarers.^56-59 Aazami et al⁶⁰ demonstrated that higher levels of job satisfaction contribute to better health. It can be concluded that satisfied workers are in better health condition, so seafaring organizations should consider different ways to improve seafarers’ job satisfaction.

There is a body of studies among seafarers that have identified different determinants of job satisfaction, such as resilience,⁵⁷ psychological capital,⁶¹ and personal hardiness,⁶² so it is crucial to apply secondary-level interventions that are likely to contribute to better stress coping skills.⁶³ Being able to cope with stress reduces possible burnout⁶⁴ and improves psychological well-being.⁶⁵ Besides different occupational stress interventions tailored to the individual level, it is a top-priority for seafaring organizations to plan and implement primary-level interventions which reduce or remove external stressors such as long working hours that disrupt circadian rhythm.

Chronic pain caused by disrupted circadian rhythm has been well-documented in working populations other than seafarers. For example, night shift work may result in lower back pain,^66,67 chronic musculoskeletal pain,⁶⁸ and reduced pain thresholds.^68,69 Although we have not examined the incidence of chronic pain in our study, it is possible to assume that some participants experience chronic pain, and this may result in sleep-wake disturbances.⁷⁰ Therefore, future studies should consider the chronic pain status as another variable that might deteriorate sleep on board, considering Oldenburg et al¹¹ results that noise and vibration are stressors that impact sleep on board. Other primary-level interventions ought to focus on improving the quality of life on board by introducing various social events on board, offering opportunities for leisure activities, and improving nutrition and Internet access.⁷¹ Improving the quality of life on board is likely to result in improved mental health, which directly contributes to lower somatic symptoms level in our study. These results may be explained by considering somatization as the relationship between psychological distress and somatic symptoms,²⁸ which may lead to significant problems caused by excessive thoughts, symptoms, behaviors, and feelings related to experienced symptoms, and impact daily life.⁷² Mostafaei et al⁴⁸ report that stress, anxiety, and depression exacerbate somatic symptoms, so it is important to provide a variety of mental health programs intended for seafarers since better mental health serves as a protective factor for experiencing different somatic symptoms. During the COVID-19 pandemic, different stakeholders in the seafaring industry implemented various measures to tackle the pandemic and strengthen seafarers’ well-being which included a reduction in overtime hours, professional counseling services, an increase in recreational, Wi-Fi data and food allowances, meditation, etc.⁷³ It is crucial to continue providing the aforementioned measures to further strengthen seafarers’ mental health and well-being. Abila and Acejo⁷⁴ highlight the importance of educating seafarers in the field of mental health, which would provide seafarers with useful information about mental health care, while Sampson and Ellis⁷⁵ provide a set of recommendations and measures for companies and relevant stakeholders aimed to improve seafarers’ mental health and well-being.

Our finding that sleep duration on board mediates the relationship between job satisfaction as a predictor and somatic symptoms as a criterion variable complemented with results from Ellis et al⁷⁶ who emphasize that less than a quarter of seafarers have adequate rest, points out the need to develop measures that are bound to improve seafarers’ sleep on board. Hence, sleep hygiene programs ought to be implemented by seafaring companies and tailored to seafarers’ individual needs.⁷⁷ Moreover, improved seafarers’ job satisfaction might contribute to better sleep, as Hemmati-Maslakpak et al⁷⁸ reported in a sample of nurses, and according to the results of our study, lead to fewer somatic symptoms.

The results of the qualitative study (Study 2) provide further clarification on the results of the quantitative study (Study 1), which had only one question concerning the on board sleep length. The themes that have emerged in the thematic analysis give us a deeper understanding of sleep difficulties, the numerous negative effects of these difficulties, such as fatigue, longer reaction times and migraines, and different coping strategies seafarers use. The sleep on board difficulties (Table 3) need to be considered with particular attention by relevant stakeholders to ensure appropriate response (eg, respect sleep-wake periods). Moreover, various sleep on board consequences, such as slower reaction time, reasoning difficulties, exhaustion, and migraines impose a potential hazard in the high work-load environment which requires permanent focus. Having said that, a disturbed sleep-wake cycle does not allow sleep during free time, and this may endanger seafarers’ safety on board. Seafarers reported using medication and increased coffee consumption to deal with poor sleep quality and it was previously shown that sleep quality predicts both burnout and well-being.²⁶ Therefore, these answers to the open-ended question represent participants’ unique perspective which needs to be taken into account when planning different interventions.

The previously mentioned sleep problems indicate an increase in the workload of seafarers due to various factors, such as economic or safety factors, and this leads to a decrease in free time and the amount of sleep. Baygi et al²¹ state that the quality of sleep was mentioned as the most significant health problem they had to deal with on board, and consequently, various difficulties arise, such as physical and mental difficulties that affect the functioning of seafarers, which poses a danger to health, but also to safety at sea. The results of our study on a convenient sample of seafarers suggest that almost 40% of our sample reported having sleep difficulties.

Here presented study has several limitations. Firstly, the cross-sectional research design in the quantitative study does not allow making conclusions of causality among the variables studied. Furthermore, as it has been previously mentioned, using only one item for measuring sleep in the quantitative study is certainly not the best choice from a psychometric point of view. Therefore, future studies ought to be conducted longitudinally, use more extensive sleep measures and include more representative samples of seafarers. Nonetheless, as far as we are concerned, this is the first study that examined the relationship between some determinants of somatic symptoms in a sample of seafarers. Practical implications of our findings about the importance of primary-level occupational stress strategies, as well as maintaining and improving secondary and tertiary-level interventions, should be implemented by seafaring organizations to develop healthy organizations that “promote a state of complete physical, mental, and social well-being in their workers, which translates into superior work efficiency and performance”⁷⁹ (p. 565). Developing healthy seafaring organizations is bound to have a whole spectrum of positive outcomes on the individual as well as organizational level.

Footnotes

Acknowledgements

The author thanks all the seafarers who participated in this study and all the organizations, associations and individuals who helped with the advertisement of the study.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Marko Galić

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“ I Constantly Feel Worn Out ”: Mixed-methodology Approach to Seafarers’ Sleep on Board

Abstract

Keywords

Introduction

Aim, Research Problems, and Hypotheses

Methods

Procedure

Study 1

Study 2

Data Analyses

Results

Study 1

Study 2

Discussion

Footnotes

Acknowledgements

Declaration of Conflicting Interests

Funding

ORCID iD

References