Current state of knowledge of post-traumatic stress, sleeping problems, obesity and cardiovascular disease in paramedics
- Sandrine Hegg-Deloye1,2,
- Patrice Brassard1,
- Nathalie Jauvin2,
- Jérôme Prairie1,3,
- Dominique Larouche1,3,
- Paul Poirier4,
- Angelo Tremblay1,
- Philippe Corbeil1,3
- 1Department of Kinesiology, Université Laval, Quebec, Quebec, Canada
- 2ÉQUIPE RIPOST, Centre de Santé et de Service Sociaux de la Vieille Capitale (CAU), Quebec, Quebec, Canada
- 3Vieillissement, Centre de recherche FRSQ du Centre hospitalier affilié universitaire de Quebec, Quebec, Canada
- 4Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, Quebec, Canada
- Correspondence to Dr Philippe Corbeil, Department of Kinesiology, Université Laval, Pavillon des sports et de l'éducation physique, Local 0212, 2300 rue de la terrasse, Quebec, Canada QC G1V 0A6;
- Received 21 June 2012
- Revised 15 October 2012
- Accepted 6 December 2012
- Published Online First 12 January 2013
Purpose The impacts of emergency work on firefighters have been well documented and summarised, but this is not the case for paramedics. This paper explores the literature regarding the impact of work stress on paramedics.
Objective To identify the literature available on the effect of paramedics’ jobs on their health status.
Methods Electronic database used: MEDLINE (Ovid, PubMed, National Library of Medicine) between 2000 and 2011. Key words used for the computer searches were: paramedics, emergency responders, emergency workers, shift workers, post-traumatic symptoms, obesity, stress, heart rate variability, physiological response, blood pressure, cardiovascular and cortisol. Exclusion criteria were: studies in which participants were not paramedics, participants without occupational exposure, physical fitness assessment in paramedics and epidemiological reports regarding death at work.
Results The electronic databases cited 42 articles, of which we excluded 17; thus, 25 articles are included in this review. It seems clear that paramedics accumulate a set of risk factors, including acute and chronic stress, which may lead to development of cardiovascular diseases. Post-traumatic disorders, sleeping disorders and obesity are prevalent among emergency workers. Moreover, their employers use no inquiry or control methods to monitor their health status and cardiorespiratory fitness.
Conclusions More studies are needed to characterise paramedics’ behaviour at work. These studies could allow the development of targeted strategies to prevent health problems reported in paramedics.
Paramedics and other emergency workers represent groups of workers who are required to rescue people as quickly and efficiently as possible. To achieve this goal, workers may put their own lives at risk. Their everyday work burden is characterised by organisational and psychosocial challenges that represent stressors. The organisational challenges include, for example, workload, night and day shifts, the pressure to achieve speedy response times, economic efficiency and variable waiting periods between calls.1 The psychosocial challenges are related to emotionally demanding work environments due to exposure to potentially traumatic events or critical incidents, repeated incidents in a short time frame, care for a dependent population, professional conflict and emotional reaction to persons who may be quite ill or near death.2 In addition, these workers, who differ in terms of their individual abilities (eg, physical capacity, personality traits, height, age, experience, lifestyle), must operate in a variety of environmental conditions; thus, they must adapt their work strategies to patient characteristics (body weight, state of consciousness, aggressiveness) as well as their colleagues’ work capacity. All these constraints create physical, physiological and psychological demands before, during and after an emergency call-out. In accordance with Selye's theory,3 persistent exposure to stressors may progressively lead to overactivity of autonomic nervous system, resulting in various maladaptive outcomes, such as the development of mental health impairments, cardiovascular diseases (CVD), metabolic syndrome and obesity.4 ,5 Obesity may also be a risk factor for CVD in paramedics. Unfortunately, few studies have investigated the health status of these workers. This paper provides an overview of recent studies performed to characterise the impact of work stress on paramedics.
We conducted a search of articles published between 2000 and 2011 using MEDLINE (Ovid, PubMed, National Library of Medicine). Key words used for the computer searches were: paramedics, emergency responders, emergency workers, shift workers, post-traumatic symptoms, obesity, stress, heart rate variability, physiological response, blood pressure (BP), cardiovascular and cortisol.
Studies were included in our review if the experimental protocol was conducted among professional workers and included a literature review. Experimental studies with fewer than six participants, and observational studies with a questionnaire response rate below 60% were not included. Forty-eight studies published from January 2000 to July 2011 were found, 25 of which were included in this review. Table 1 summarises the main results of these studies.
Occupational stress indicators
Occupational stress can be defined as physical and emotional responses occurring when the requirements of the job overload the workers’ adaptation capabilities.3 ,6 Paramedics are exposed to stressful events in the line of duty.7 ,8 During these periods of stress, the magnitude of the stress response can be identified through cortisol and catecholamine levels as well as cardiorespiratory reactions (table 2).
For paramedics, an elevation in the cortisol level at work was observed in comparison with days off.4–6 Also, higher secretion of cortisol in the morning was reported on days in emergency service than on days in patient transport, suggesting adjustment to forthcoming demanding tasks.4 It has been reported that paramedics who complained the most about pain and health problems had higher cortisol levels at work in the morning, than those with few complaints.6 This is in agreement with another study that showed associations between cortisol level and anxiety and depression symptoms among rescue workers. Furthermore, Aasa et al (2006) found that higher cortisol values at work were associated with worry about work conditions but not with psychological demands, measured with the demand-control-support instrument.9 They suggested that worry about work conditions is associated with physiological arousal.6 A major limitation on these studies is that the 24-h work shifts studied were, as mentioned by the authors, not as demanding as shifts when major accidents occur, and that paramedics in general relate their stress levels to ‘a worst imaginable disaster’ or other difficult situations.
During a mental, emotional or physical stress response, the elevation of epinephrine and norepinephrine levels increases cardiac output and systemic vascular resistance, which can result in systemic artery and vein vasoconstriction, leading to greater risk of developing CVD.10 The exacerbated cortisol response leads to an alteration in homeostasis among the sympathetic and parasympathetic nervous systems and the hypothalamic pituitary adrenal (HPA) axis. These alterations can contribute to the development of different pathologies, such as arterial hypertension and CVD.3 Two recent studies addressed this issue by quantifying the contributions of sympathetic and parasympathetic nervous activity in paramedics.6 ,11 Both studies showed a work-related decrease in parasympathetic activity, mostly during night and morning work. To our knowledge, no study of paramedics has investigated heart rate variability, a known autonomic nervous system marker that correlates with the risk of developing a CVD.
The assessment of occupational stress has also been characterised by the use of self-report methodologies. A commonly used model for investigating work-related psychosocial factors related to occupational stress is the demand-control-support model introduced by Karasek et al.9 In this model, stress occurs in workers facing high psychological workload demands or pressure combined with low control or decision latitude in meeting those demands. High workload was identified as one of the most frequent and severe stressors among Norwegian ambulance personnel.12 Social support is a moderator and tends to reduce psychological stressors. However, most studies show a lack of social support among paramedics faced with the frequency of shocking events.13 ,14 It has been shown that a lack of support from coworkers and working overtime, are also strongly related to the severity of stressors.12 ,15 Along the same lines, a cross-sectional self-administered questionnaire study reported a high perceived effort combined with low perceived reward.16 This result was associated with poor mental health (eg, effort reward imbalance, general health questionnaire) in a Swiss sample of 333 paramedics.16
Some authors have suggested that individual differences in stress regulation (eg, neuroticism, introversion, self-efficacy) might explain the high level of emotional distress symptoms among ambulance personnel.12 ,15 ,17 Individuals who can regulate distress may experience briefer postincident distress and fewer long-term emotional difficulties. A significant but weak relationship was observed between individual differences and severity of occupational stressors (explaining, on average, 3.7% of the variance).12 Sterud et al (2008) reported that acute stressors at work were related to health symptoms, such as fatigue and post-traumatic symptoms. Clinical levels of depression (9%) and anxiety (23%) were also reported in another study.18 ,19
Consequences of stress for paramedics
Post-traumatic stress disorder
Post-traumatic stress disorder (PTSD) represents a common anxiety disorder that develops after exposure to a terrifying event or repeated shocking situations. The concept of stress shows that repeated exposure to shocking events can lead to psychological exhaustion.3 Thus, each new shocking event becomes one more risk factor for the development of PTSD. The exhaustion stage and PTSD promote headaches, gastrointestinal distress, immune system impairments, discomfort and sleeping problems, suggesting an association with chronic stress at work.13 The impact of PTSD on paramedics’ health has been the subject of several studies2 ,7 ,13 ,14 ,17 ,18 ,20 ,21(table 1).
Alexander and Klein (2001) observed that 90 out of their sample of 160 Scottish paramedics and technicians had experienced a particularly shocking event in the previous 6 months. Several studies have reported that a high percentage of paramedics (62% in Sweden, 100% in the USA, 93% in Germany) experienced acute stress during their shifts, especially in situations involving management of their own emotions.2 ,17 ,20 ,22 Based on the results of their study of emergency medical technicians and paramedics, Mishra et al23 identified two main factors associated with the risk of developing PTSD. The first is re-experience of the shocking event (27%), which is associated with psychological distress, disturbing dreams, flashbacks and physical reactions upon remembering the traumatic event. Second, hyperarousal, characterised by sleep disturbances, difficulty concentrating and a hypervigilant attitude, is also an important feature. The consequences of PTSD have been associated with significantly impaired social functioning, higher rates of depression and poorer physical health.
Considering the overall prevalence of PTSD reported (20% in emergency work vs 5% in the general population),7 ,18 ,21 it is imperative to develop strategies to prevent and treat mental health problems associated with emergency work. These strategies need to take into account the severity and the magnitude of the problem.
Normal sleep consists in cycles of rapid eye movement and non-rapid eye movement (NREM) sleep. NREM sleep comprises three stages: (1) stage 1 sleep (2) stage 2 sleep and (3) slow-wave sleep (or deep sleep). The last stage is characterised by a reduction in heart rate, BP and sympathetic nervous activity, and an elevation of parasympathetic nervous activity to restore baseline values.24 Additionally, there is an inhibition of the HPA axis that releases cortisol. When sleep is delayed in the evening, the sleep cycle is shortened and slow-wave sleep is reduced, thereby altering the return to baseline values.
Several authors suggest that there is a negative feedback loop between PTSD and sleep disorders: more than 80% of people with PTSD report sleep difficulties immediately after the shocking event, and 70% after 6 months.25 Findings suggest that sleep disturbances occurring early after trauma exposure are associated with an increased risk of PTSD at subsequent assessments conducted up to 1 year later. The prevalence of sleeping problems was found to be significantly associated with psychological demands on paramedics in Sweden.13 A review of the literature on paramedics, and the effects of shift work on sleep characteristics identified a high proportion of shift workers who reported fatigue, work stress, low job satisfaction and poor mental and physical health.26 This review concludes that there is a lack of literature describing the effects of shift work on sleep among paramedics.
Yet, the relationship between shift work and the health of other workers has been extensively studied. Data from a recent study showed that chronic exposure to circadian misalignment, such as rotating shift work, is associated with higher body mass index (BMI) and altered biomarkers of atherosclerosis. Moreover, several cross-sectional and prospective studies have found associations between short sleep duration and increased risk of a greater percentage of body fat, weight gain over time, prevalence of arterial hypertension and CVD caused by an increase in cardiac sympathetic activity.27 Such associations between shift work and changes in emergency workers’ health may also be present, but more studies are needed to specifically demonstrate these relationships.
Eating behaviour, nutrition and obesity
Both, shift workers and paramedics may have diverse eating behaviours.28 It is widely recognised that weight problems result from several psychological and environmental factors, such as lack of control, depression, anger or loneliness, interpersonal difficulties, difficulty expressing emotions, media promotion and proximity of fast food.
Of interest for the present text are the effects of acute and chronic stress on eating behaviour by means of hormone actions (table 2). During acute stress, the alarm and adaptation stages inhibit eating and promote the fight-or-flight response.29 After the acute reaction and during stress recovery, the baseline levels of epinephrine, norepinephrine and cortisol are restored, promoting eating sensations (table 2) and, consequently, food intake.3 With chronic stress, the normal body reaction declines and the recovery is deficient; high levels of hunger hormones are maintained for an extended period of time.29 In the case of paramedics, work that involves unpredictable emergency call-outs and variable waiting periods between calls is associated with irregular meal timing.1 Regular meal timing influences satiety and helps prevent weight gain.30
Several studies show a high prevalence of obesity among firefighters, but few have addressed this issue among paramedics.28 ,31 ,32 A recent study reported high BMI values in firefighter and paramedic recruits (mean of 28.5 kg/m2), and a high percentage of workers were considered overweight (77% with a BMI >25 kg/m2), or obese (33% with a BMI >30 kg/m2).32 Another study reported on perceived stress, lack of leisure time and prevalence of obesity among prehospital emergency professionals.16 Longitudinal and quantitative studies are necessary to clarify the eating behaviours and physical activity associated with obesity and CVD risk.
Moreover, recent findings indicate that caloric intake after 20 : 00 may increase the risk of obesity, after adjustment for sleep duration and timing.33 For example, Baron et al (2011) found a higher prevalence of obesity in shift workers (n=33, prevalence of BMI >30 kg/m2=27.2%) than in day workers (n=89, prevalence of BMI >30 kg/m2=23.7%, p=0.001). A recent literature review of 95 studies related to shift work reported a high prevalence of overweight and obesity among shift workers than in day workers.24 It is reported that longer exposure to shift work increases the risk of developing obesity without any difference in total energy intake. In fact, eating patterns are modified, with a reduction in energy expenditure for shift workers in comparison with day workers. This desynchronism in digestion may contribute to the acceleration of metabolic disorders.
With regard to paramedics, the combination of occupational stress, sleeping problems and eating disorders could contribute to obesity, physical inactivity and CVD.32 Body weight is commonly associated with the prevalence of arterial hypertension, a deteriorating lipid profile, and increased risk factors for CVD.
CVDs are the leading cause of mortality worldwide, accounting for 29% of global mortality in 2004. CVDs include stroke, coronary heart and peripheral arterial diseases. They represent an important public health problem and an economic burden for society and the healthcare system.34 Many risk factors are associated with CVD: tobacco, physical inactivity, obesity/overweight, hypertension, dyslipidaemia and diabetes.35 For instance, some studies emphasise the negative impact of time spent sitting (>3 h/day) as an indicator of overweight and obesity after adjusting for age, occupation and physical activity.35 In Holland, the sitting time per shift for paramedics represents more than half their working time, as reported by a field study.36
Eighteen per cent of on-duty deaths among paramedics in the USA result from cardiovascular incidents, as reported in a 6-year follow-up.37 Barrett et al38 used a self-report survey to assess the prevalence of CVD risk factors in urban paramedics (n=85). Their study revealed that 48% of workers presented a high level of CVD. Among paramedics, tobacco use, hypertension and high cholesterol were reported in 19%, 13% and 31% of individuals, respectively. However, very few studies have reported a high level of CVD for paramedics.39 ,40
Conclusion and perspectives
In conclusion, it seems clear that paramedics accumulate a set of risk factors, including acute and chronic stress and post-traumatic disorders that can lead to the development of CVD. Moreover, post-traumatic disorders, sleep problems and obesity are prevalent among paramedics.
The combination of personal cardiovascular risk factors and high demands of physical work may contribute to sudden cardiac death in this population. In the general population, many strategies are focused on reducing risk factors for health, such as nutritional programs to prevent overweight and obesity, promotion of physical activity, the campaign against tobacco and psychological support. No such programs exist for emergency workers, who are at particular risk. Moreover, both organisationally and individually based interventions may be necessary to minimise emotional disorders among paramedics.
Since paramedics may also be exposed to several risk factors, we believe that further studies are needed to better characterise their health conditions. Finally, more studies are needed to characterise their behaviour at work and risk of CVD. These studies could allow the development of targeted strategies to prevent the health problems reported in these types of jobs.
This study was partly supported by a grant from the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) to PC. Paul Poirier is a senior clinician-scientist of the Fonds de la Recherche en Santé du Québec (FRSQ).
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.