STRENGTHS AND LIMITATIONS OF THIS STUDY
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The study used well-established tools, such as the Chinese Occupational Stress Inventory and the Maslach Burnout Inventory, to effectively assess the stress, burn-out and sleep quality of ambulance drivers, ensuring the reliability of the findings.
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A substantial sample size of 213 participants provides a solid foundation for generalisable insights specifically related to ambulance drivers in Hengyang, China, enhancing the relevance of the research.
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The cross-sectional design limits the ability to draw causal inferences between stress, burn-out and sleep quality; future longitudinal studies would better elucidate these relationships over time.
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Relying on self-reported measures may introduce response bias, and future research could benefit from incorporating objective measures or data from multiple informants for a more comprehensive evaluation.
With the rapid development of society, the pace of people’s work and life has been continuously accelerating. The current employment environment also imposes higher demands on workers in various industries. Work pressure is unavoidable, and occupational hazards are becoming more prominent.1 Occupational stress has become a hot topic of occupational health concern both domestically and internationally.2 Occupational stress refers to the physiological and psychological reactions caused by an imbalance between objective demands and individual coping abilities under specific occupational conditions.3
As a specific mode of transportation, ambulances undertake social and public welfare functions such as prehospital emergency care, rescue during sudden public incidents, and isolation and transportation of infectious patients. They are vital mobile medical emergency facilities crucial to human life safety.4 Ambulance drivers are responsible not only for ensuring safe travel but also for mastering the use of onboard emergency equipment, acquiring first aid skills and coordinating with medical personnel accompanying the ambulance, thus embodying the basic function of emergency medical care.5 Therefore, ambulance drivers play a crucial role in prehospital emergency care teams, carrying out the critical task of transporting patients from the scene to the hospital.
Meanwhile, ambulance drivers constitute a relatively vulnerable and often overlooked group, deserving attention. Due to the unique nature of prehospital emergency care work, they are frequently exposed to various risk factors and endure long working hours, high labour intensity and susceptibility to discrimination.6 As a result, ambulance drivers often experience extreme fatigue, leading to a range of physical and mental health issues such as occupational stress, burn-out and sleep disorders.
Occupational burn-out refers to a state of physical and mental exhaustion and depleted psychological resources experienced by workers during production operations and prolonged exposure to stressful environments increases the risk of occupational burn-out.7 Sleep, as the fundamental guarantee of physiological activities, directly impacts an individual’s cognitive ability and emotional state when its quality is poor, leading to heightened interpersonal conflicts, fatigue at work and the potential aggravation of various acute and chronic diseases.8 Research has indicated that occupational stress can impair the body’s regulatory capacity, leading to an imbalance in physical performance and making individuals more susceptible to sleep disorders.9 In recent years, there has been limited research on the pathways and underlying mechanisms through which occupational stress among ambulance drivers affects sleep quality.
This study conducted a cross-sectional survey to investigate the current status of occupational stress, burn-out and sleep quality among ambulance drivers in Hengyang, China. We think that ambulance drivers experience significant levels of occupational stress and burn-out, which are negatively associated with their sleep quality. Specifically, we hypothesise that higher levels of occupational stress among ambulance drivers will be positively correlated with higher levels of occupational burn-out. Higher levels of both occupational stress and burn-out will be associated with poorer sleep quality among ambulance drivers. Occupational burn-out will mediate the relationship between occupational stress and sleep quality, suggesting that higher levels of stress contribute to burn-out, which in turn negatively impacts sleep quality. These hypotheses guide the investigation into understanding the interplay between occupational stress, burn-out and sleep quality among ambulance drivers.
It analysed the impact pathways of occupational stress and burn-out on the sleep quality of ambulance drivers, aiming to provide a reference basis for improving the sleep quality and overall well-being of ambulance drivers.
Materials and methods
Participants
From October to December 2023, a convenience sampling method was used to conduct a questionnaire survey among on-duty ambulance drivers receiving health check-ups at the Health Management Center of the Second Affiliated Hospital of South China University. Due to the government’s welfare policy, it is required that all ambulance drivers in Hengyang undergo routine medical examinations. Therefore, we have the opportunity to involve ambulance drivers from all tertiary hospitals in Hengyang in the investigation at the hospital examination centre. Prior to the survey, the purpose and methods of the study were explained to the ambulance drivers, and their verbal consent was obtained before distributing and collecting the questionnaires on the spot.
Inclusion criteria: (1) age ≥18 years old; (2) engaged in ambulance work for ≥1 year and (3) willing to participate in the questionnaire survey.
Exclusion criteria: ambulance drivers with serious heart, lung, liver or kidney diseases.
Criteria for excluding invalid questionnaires: (1) questionnaires with more than three missing items and (2) questionnaires showing obvious patterns in responses.
Methods
General Information Questionnaire
A self-designed questionnaire was used to collect general information, including gender, marital status, monthly income, the number of children, years of work experience, work patterns and average daily working hours.
Occupational Stress Scale
The Chinese Occupational Stress Reaction Scale was used in this study,10 consisting of three dimensions: cognitive stress reactions (three items), psychological stress reactions (seven items) and physiological stress reactions (five items). The scale employed a 5-point rating system, ranging from ‘never’ to ‘all the time’, with scores of 0–4 assigned accordingly. The total score ranged from 0 to 60, with higher scores indicating higher levels of occupational stress. In this survey, the Cronbach’s α coefficient for the scale was 0.810.
Occupational Burnout Scale
The Occupational Burnout General Scale was used to assess the occupational burn-out status of ambulance drivers.11 The scale consists of three dimensions: emotional exhaustion (five items), depersonalisation (four items) and reduced personal accomplishment (six items). Each item is rated on a scale from ‘never’ to ‘every day’, with scores ranging from 0 to 6. The total score ranges from 0 to 90, with higher scores indicating a higher level of occupational burn-out. In this survey, the Cronbach’s α coefficient for the scale was 0.912.
Sleep Quality Scale
The Pittsburgh Sleep Quality Index was used to assess the sleep status of ambulance drivers over the past month.12 The scale comprises 19 self-rated items and 5 other-rated items, with only 18 self-rated items contributing to the scoring. It covers seven aspects including subjective sleep quality, sleep latency and sleep efficiency, with each item scored from 0 to 3. The total score ranges from 0 to 21, with higher scores indicating poorer sleep quality. A total score of 7 or higher is indicative of sleep disturbances. In this survey, the Cronbach’s α coefficient for the scale was 0.880.
Statistical analysis
Data processing and analysis were conducted by using SPSS V.25.0 and Mplus V.7.0. Descriptive statistics were presented as percentages for categorical data and as 
±s deviation for continuous data. Pearson correlation analysis was used to examine the correlations among occupational stress, sleep quality and occupational burn-out in ambulance drivers. A fitting model with occupational burn-out as the mediating variable was constructed using Mplus V.7.0 software. The bootstrap method was employed to test the mediating effects, with a significance level set at α=0.05.
Patient and public involvement
No patients were directly involved in the design, conduct or reporting of this research. As this study focuses on occupational stress, burn-out and sleep quality among ambulance drivers in Hengyang, China, the involvement of patients in the traditional sense was not applicable. However, the research participants—ambulance drivers—were engaged in the study through their voluntary participation in the survey conducted from October 2023 to December 2023. The findings will be disseminated to the participants and relevant stakeholders in the field, contributing to potential improvements in occupational health and well-being for ambulance drivers.
Results
A total of 213 questionnaires were distributed for this study, with 199 valid questionnaires collected, resulting in an effective response rate of 93.4%. Among the 199 included ambulance drivers, all were male (100%); ages ranged from 18 to 30 years old with 16 individuals (8%) and 31 to 50 years old with 183 individuals (92%); 157 participants were married (78.9%) while 42 were unmarried (21.1%); 7 individuals had an education level of junior high school or below (3.5%) and 192 individuals had a high school or technical secondary school education (96.5%).
Occupational stress, burn-out and sleep quality scores of ambulance drivers
The occupational stress score of 199 ambulance drivers in Hengyang, China was (42.07±11.33), the total score for occupational burn-out was (57.23±10.11) and the total score for sleep quality was (8.13±1.90). Additionally, 74.7% of ambulance drivers were found to have sleep disturbances.
Single-factor analysis of occupational stress, occupational burn-out and sleep quality scores among ambulance drivers in Hengyang, China.
Comparison of occupational stress scores among ambulance drivers based on different age groups, monthly income levels, the number of children, work patterns and average daily working hours revealed statistically significant differences (p<0.05). Similarly, significant differences (p<0.05) were observed in the comparison of occupational burn-out scores among ambulance drivers based on different age groups, monthly income levels, years of work experience and average daily working hours. Furthermore, differences in sleep quality scores among ambulance drivers based on gender, monthly income levels and work patterns were also found to be statistically significant (p<0.05) (table 1).
A single-factor analysis of occupational stress, burn-out and sleep quality scores among ambulance drivers with different demographic characteristics
Supplemental material
Correlation analysis of occupational stress, occupational burn-out and sleep quality among ambulance drivers
The Pearson correlation analysis results indicate that occupational stress among ambulance drivers in Hengyang, China is positively correlated with occupational burn-out and sleep quality scores (r=0.528, 0.447, p<0.01). Additionally, there is a positive correlation between occupational burn-out and sleep quality scores (r=0.394, p<0.01) (table 2).
Analysis on the occupational stress, burn-out and sleep quality of ambulance drivers (n=199, r)
Mediation analysis of occupational burn-out among ambulance drivers: the mediating effect between occupational stress and sleep quality
In Mplus software, a mediation model was established with occupational stress as the independent variable, occupational burn-out as the mediating variable, and sleep quality as the dependent variable (figure 1). The fit indices showed that the χ2 to df ratio (χ2/df) was 2.52, the Comparative Fit Index was 0.913, the Tucker-Lewis Index was 0.970, the root mean square error of approximation was 0.065 and the standardised root mean square residual was 0.062, indicating an acceptable fit of the research model. Using the Bootstrap method for multiple random sampling in testing the mediating effects, the results revealed that the direct effect of occupational stress on the sleep quality of ambulance drivers was 0.471 (95% CI 0.221 to 0.728) while the indirect effect of occupational stress on the sleep quality of ambulance drivers through occupational burn-out was 0.168 (95% CI 0.079 to 0.262), accounting for 26.09% of the total effect (table 3).
Mediating model of job burn-out among ambulance drivers between occupational stress and sleep quality. (e1–e14 are residual terms.)
Results of the mediation analysis on the role of job burn-out as a mediator between job stress and sleep quality among ambulance drivers
Discussion
The levels of occupational stress, occupational burn-out and sleep quality among ambulance drivers
When the rewards obtained by workers in their positions do not match the labour input, it is easy to cultivate occupational stress.13 Research has shown that prolonged exposure to the stressful state of occupational stress can not only cause psychological health damage such as irritability, anger, anxiety and depression, but also affect family harmony and work status, and in severe cases, may lead to safety accidents.14–16 The results of this survey show that the occupational stress score of 199 ambulance drivers is (42.07±11.33) points, indicating that the level of occupational stress among ambulance drivers is at a moderate to high level. Univariate analysis results revealed that age, monthly income, the number of children, work pattern and average daily working hours can influence the level of occupational stress among ambulance drivers. It is worth noting that ambulance drivers who are older, have lower incomes, have more children, work in shifts and have longer working hours experience higher levels of occupational stress. Analysing the possible reasons, the work of ambulance drivers in prehospital first aid is often the last choice for many older individuals. The older they are, the more difficult it is to find re-employment, leading to higher levels of occupational stress. Ambulance drivers with low income and many children often bear heavier life pressures, as their work does not bring a sense of income satisfaction and achievement, leading to insufficient self-confidence and increasing the sense of occupational stress. Shift patterns and long-term front-line work make ambulance drivers more prone to feelings of fatigue and lack of concentration during working hours, thereby increasing occupational stress. Therefore, society should pay attention to the work patterns of ambulance drivers, reasonably arrange working hours, and at the same time, reasonably improve income levels to reduce occupational stress.
The WHO defines occupational burn-out as a comprehensive syndrome characterised by physical and emotional exhaustion, as well as reduced work efficiency due to prolonged exposure to excessive work pressure without effective relief.17 The results of this survey indicate that the total score for occupational burn-out among ambulance drivers in Hengyang, China is (57.23±10.11), suggesting a less-than-optimistic state of occupational burn-out among ambulance drivers. This may be attributed to the fact that ambulance drivers are constantly exposed to a highly stressful work environment, and the monotonous and high-demand nature of driving ambulances for extended periods poses a severe challenge to their physical and mental well-being, making them more susceptible to experiencing occupational burn-out. Furthermore, the survey results also demonstrate that older age, longer years of service, longer average daily working hours and lower income levels are associated with more severe levels of occupational burn-out among ambulance drivers. This could be due to the fact that over time, older and more experienced ambulance drivers consistently operate in a stressful work environment characterised by high labour intensity, long working hours, monotonous and unfulfilling tasks and low income, which results in insufficient occupational recognition and fulfilment. Prolonged stress without adequate relief accumulates, leading to increasing feelings of fatigue and a lack of enthusiasm towards repetitive tasks, ultimately resulting in both physical and mental exhaustion. Consequently, the level of occupational burn-out is higher among ambulance drivers.
Research has indicated that good sleep quality not only rapidly reduces physical fatigue and restores energy in the body but also contributes to maintaining physical and mental health, as well as fostering positive interpersonal relationships.18 Conversely, poor sleep quality characterised by irregular sleep patterns and difficulties in maintaining sleep can lead to decreased memory and reaction times, as well as physical and mental issues such as disrupted blood pressure, irritability and fatigue, which can increase the risk of work-related errors and safety hazards.19–21 The results of this survey indicate that the total score for sleep quality among ambulance drivers in Hengyang, China is (8.13±1.90), with a prevalence of sleep disorders at 74.7%. This suggests a significant severity of sleep problems among ambulance drivers, which may be associated with the nature of their work. Furthermore, the survey results show that low-income sanitation workers face high life pressures, making it difficult to maintain a satisfactory standard of living and some individuals in the low-income group may take on multiple part-time jobs after work, leading to poor sleep quality. In addition, compared with regular daytime work, shift work can disrupt the normal biological rhythms of ambulance drivers, particularly causing disturbances in their circadian rhythms, which can prevent adequate physical and mental recovery and affect sleep quality.
An analysis of the relationship between occupational stress, occupational burn-out and sleep quality among ambulance drivers
The results of this survey indicate that occupational stress among ambulance drivers is positively correlated with both occupational burn-out and sleep quality. This suggests that as occupational stress levels increase, the severity of occupational burn-out also intensifies among ambulance drivers. This is because occupational stress can simultaneously impact various aspects of ambulance drivers’ physiology, psychology and behaviour. When ambulance drivers are unable to effectively cope with occupational stress at work, they may exhibit a lack of enthusiasm, patience and reluctance to actively engage in their duties, leading to occupational burn-out. Therefore, occupational stress can be considered an early indicator of occupational burn-out and should not be overlooked. Furthermore, the more severe the degree of occupational burn-out, the poorer the sleep quality among ambulance drivers. On analysis, occupational burn-out, as a psychological syndrome resulting from individuals’ inability to cope with work pressures, can lead to physical and mental fatigue and exhaustion under work-related stress, which in turn can foster the growth of negative emotions and cause individuals to be preoccupied with thoughts before falling asleep, thereby affecting sleep quality. Additionally, higher levels of occupational stress among ambulance drivers are associated with poorer sleep quality. This may be attributed to the long-term chronic stress response induced by occupational stress, which can lead to emotional disturbances, reduced attention, increased psychological pressure, and ultimately have an adverse impact on sleep quality.
The occupational burn-out of ambulance drivers acts as a mediator between occupational stress and sleep quality
The results of this survey indicate that occupational stress not only directly and positively influences the sleep quality of ambulance drivers but also indirectly affects their sleep quality through occupational burn-out. As an indispensable professional group in prehospital emergency care teams, ambulance drivers in Hengyang, China, work long hours each day with generally low material or spiritual rewards. They often face a series of practical issues such as family living expenses and difficulties in re-employment. As a frequently overlooked professional group, they endure monotonous work and stress for extended periods with limited effective psychological outlets, inevitably leading to psychological issues such as occupational stress and burn-out, ultimately resulting in poor sleep quality. Some researchers believe that occupational stress forms the objective basis for the occurrence of occupational burn-out when continuous and substantial job pressure cannot be effectively relieved, it leads to occupational stress.22 As individual experiences of dissatisfaction accumulate due to occupational burn-out in the workplace, they generate aversion and indifference towards work, perpetuate negative attitudes throughout the entire work process, create overwhelming pressure and negative emotions, prevent individuals from finding effective outlets, result in reduced energy and chronic fatigue, and subsequently affect night-time sleep quality.23
Additionally, the working hours and nature of work for ambulance drivers may also impact their sleep quality. Irregular work schedules, night shifts and high work intensity may disrupt their sleep and lower its overall quality. Prolonged poor sleep quality may lead to a range of physical and psychological health issues.
In ambulance drivers, there exists a mutual relationship between work pressure, burn-out and sleep quality. Elevated work pressure and burn-out may lead to a decrease in sleep quality while deteriorating sleep quality may further increase the degree of work pressure and burn-out. This interaction may form a vicious cycle, negatively impacting the physical and mental health of the drivers.
Therefore, in order to safeguard the physical and mental well-being of ambulance drivers, it is necessary to implement measures aimed at alleviating their work pressure and burn-out, as well as improving their sleep quality. This requires giving more attention and care to ambulance drivers. For example, providing training and support to help drivers effectively cope with emergency situations and work pressure; establishing reasonable work schedules to ensure that drivers have sufficient rest and adequate sleep; implementing health promotion programmes to encourage psychological adjustment and physical exercise among drivers; appropriately increasing labour remuneration to genuinely respect their professional status and labour value, thereby reducing occupational stress and burn-out among ambulance drivers, improving sleep quality and ultimately maintaining their physical and mental health.
Limitations
However, this study still has certain limitations: (1) Cross-sectional design: The study employed a cross-sectional design, which limits the ability to establish causal relationships between occupational stress, burn-out and sleep quality among ambulance drivers in Hengyang, China. Cross-sectional studies provide a snapshot at a single point in time and cannot account for changes over time or the directionality of effects. Longitudinal studies would be beneficial to capture the dynamic nature of these variables and provide stronger evidence for causal relationships. (2) Sampling and generalisability: The study’s sample consisted of 213 ambulance drivers from Hengyang, China, which may not fully represent the diversity of ambulance drivers across different regions or healthcare systems. There might be variations in occupational stress, burn-out levels and sleep quality among ambulance drivers in other parts of China or in different countries with distinct cultural and healthcare contexts. Therefore, caution should be exercised when generalising these findings beyond the specific sample studied. (3) Reliance on self-report measures: The study relied on self-reported measures to assess occupational stress, burn-out and sleep quality, which could introduce response biases such as social desirability or recall bias. Self-reported data may not always accurately reflect the actual experiences of ambulance drivers. Future research could consider incorporating objective measures (eg, physiological indicators of stress, sleep patterns measured by actigraphy) or multiple informants (eg, supervisor assessments of burn-out) to enhance the validity and reliability of findings.
Conclusion
Occupational stress has a direct positive predictive effect on the sleep quality of ambulance drivers while occupational burn-out partially mediates the relationship between occupational stress and sleep quality. Reducing occupational stress and burn-out is beneficial for improving the sleep quality. This suggests that hospital administrators can reduce the level of occupational burn-out among ambulance drivers and improve their sleep quality and overall well-being by implementing corresponding measures to ambulance drivers’ sense of occupational stress.
Implications
Given the suboptimal sleep quality among ambulance drivers in China, and the direct correlation between occupational stress and sleep quality, addressing occupational stress levels and burn-out is crucial. The positive mediating role of occupational burn-out underscores the need for interventions focusing on stress management and burn-out prevention within the clinical practice of supporting ambulance drivers. By reducing occupational stress and burn-out, healthcare providers can significantly enhance the sleep quality and overall well-being of ambulance drivers.
Data availability statement
Data are available on reasonable request.
Ethics statements
Patient consent for publication
Ethics approval
This study involves human participants but this study was exempted by the Medical Ethics Committee of the Second Affiliated Hospital of South China University. Participants gave informed consent to participate in the study before taking part.
Acknowledgments
We gratefully acknowledge the support and assistance of various individuals and organisations throughout the course of this research. Furthermore, we would like to thank the participants who generously volunteered their time and contributed to this study. Their cooperation and willingness to participate were essential to the success of our research endeavours.
This post was originally published on https://bmjopen.bmj.com