Reduced professional efficacy is associated with a blunted salivary alpha-amylase awakening response
Introduction
The relationship of discrete measures of the burnout syndrome with indices of stress physiology is not well understood [1]. The two primary neuroendocrine response systems activated when faced with a perceived threat are the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic-adrenal-medullary (SAM) system [2,3]. Neuroendocrine stress and burnout research has typically focused on HPA axis reactivity as most researchers consider salivary cortisol levels a reliable indicator of HPA axis activity and adaptation to stress [[4], [5], [6]]. However, less is known about the surrogate autonomic nervous system (ANS) marker, salivary alpha-amylase (sAA) [7]. Elevated levels of sAA concentrations reflect ANS activity in response to stress and involve activation of both the parasympathetic and sympathetic nerves [[8], [9], [10]]. Studies have demonstrated that an increase in sAA levels can be expected in response to acute stress stimuli when autonomic activation is high in a range of contexts [9,11,12]. However, only a small number of studies have investigated associations between the sAA awakening response (sAA-AR) and chronic work stress. These studies have produced inconsistent results including finding perceived work stress to be associated with a less steep sAA-AR among educators [13], an increase in sAA levels 30 min after awakening among health care professionals reporting high job strain [14], while others have reported no relationship between workplace stress and sAA in a group of nurses [15].
Based on the available evidence, chronic stress may impair the functioning of either the SAM or the HPA axis, or the interplay between the two systems [16]. As sAA is less likely to be influenced by variables such as age, habitual smoking, coffee consumption, and oral contraception than cortisol [15], the sAA-AR may be a more reliable indicator of psychological stress. This premise, however, requires empirical enquiry. Others have suggested that the sAA -AR measured concurrently with the cortisol awakening response (CAR) may potentially provide a better explanation of the endocrine stress response than either biomarker considered in isolation [17]. The diurnal pattern of sAA-AR is inversely related with the CAR, and typically, sAA levels decrease upon waking and then steadily rise over the course of the day [18,19]. The sAA-AR has been shown to be reactive to stress in a range of contexts [20], including the workplace [13,21]. In one of the few studies comparing the CAR and the sAA-AR within the context of occupational stress, higher states of depersonalization and ambition were associated with a blunted CAR among a group of teachers reporting chronic stress and burnout, and similarly, higher ambition and perceived stress were associated with a less steep sAA-AR [13].
The job demands-resources model (JD-R) asserts that although every occupation has its own set of specific risk factors associated with workplace stress, these factors can be classified into two general categories: job demands (e.g., high work pressure, unfavourable physical environment, emotionally demanding interactions with clients) and job resources (e.g., salary, job security, career prospects, role clarity, skill variety, autonomy) [22,23]. According to JD-R theory, job demands are related with adverse well-being and high resources are associated with improved motivation and work engagement. In this study, we focus on the interaction hypothesis. Specifically, we assess the interaction hypothesis that stress and employee burnout occur when job demands are high and job resources are low, often resulting in health impairment [22,24]. However, to our knowledge, the JD-R model has yet to consider the association of job stress with physiological indices of stress. The JD-R model is more flexible than other occupational stress models in its approach to conceptualizing workplace stress, and lends itself to being applied to various occupational settings, potentially even professional athletes [25,26].
When coupled with insufficient recovery, chronic exposure to occupational stressors can result in burnout [[27], [28], [29]], which is typically characterized by exhaustion, cynicism, and reduced professional efficacy [28]. This three-dimensional theoretical construct continues to be the predominant one in the burnout field [28] and although empirically supported by cross-sectional studies, fewer researchers have utilized a longitudinal design [[30], [31], [32]]. While much of the research originally concentrated on people-oriented, human service occupations (e.g., health care professionals, educators), the concept of burnout has also been broadened to apply to non-human service professions (e.g., assembly line workers, air traffic controllers, military personnel) [23]. However, burnout is not solely related to work as it may ensue after prolonged exposure to any situation that may be emotionally demanding e.g., athlete (amateur) burnout [33], parental burnout [34], and caregiver burnout [35]. Although burnout is a serious condition among athletes [36] and is associated with performance impairment, reduced enjoyment, depressed mood, and premature retirement from the sport, athletes have rarely been the focus of investigations assessing occupational stress and burnout.
In this study, we focused on apprentice horse jockeys as they experience high levels of work stress [37], and report chronic stressors including maintaining a consistent weight and working long hours [38]. We examined the relationships between occupational stress, burnout, and physiology across two time points reported by jockeys to represent naturally occurring ‘low’ and ‘high’ stress periods during the racing calendar [39], and assessed if individual changes in occupational stress perceptions were associated with indicators of dysregulated stress physiology across the low and high stress periods. Our previous focus group interviews with these jockeys [39] revealed the spring months as being perceived as more stressful than the winter months due to work and financial opportunities associated with the racing calendar. Essentially, the spring months are when the most prestigious races take place and it is difficult for apprentices to ‘find a ride’, and many are restricted to non-competition work (e.g., horse handling, track work). However, after this period, when the senior riders take breaks, more opportunities become available. We expected that high stress periods would correspond with poorer perceptions of stress and health (physical and mental), and with dysregulated stress physiology. Finally, we anticipated that high workplace stress and high self-reported burnout would be related to dysregulated physiological reactivity.
Section snippets
Participants
Full-time professional Australian apprentice flat-racing jockeys (aged 15–24 years; N = 32) provided data at two time points (low and high stress periods). Both apprentice and senior jockeys in Australia are considered ‘professional’ as they are licensed, full-time paid employees, and racing is their primary occupation. The sample comprised 14 males (M age = 18.1, SD = 1.5) and 18 females (M age = 19.9, SD = 2.3), representing 64% of all apprentice jockeys within the region. Participants were
Normative data
Normative comparisons revealed that our sample reported significantly higher scores for the cynicism and exhaustion scales during the high stress period (Table 1). When comparing our sample's scores on these same scales between the low and high stress time points, the sample reported significantly higher scores during the high stress period. Perceived levels of job demands and job resources, however, did not differ between the two time-points, suggesting our sample perceived that similar levels
Discussion
We investigated the associations between self-reported job stress, burnout, health, and pre-clinical stress-related biomarkers across two time points coinciding with naturally occurring ‘low’ and ‘high’ stress periods. Our main findings from the hierarchical regressions suggest that those jockeys presenting with reduced professional efficacy in the high stress period produced a ‘flattened’ sAA-AR indicative of reduced sympathetic arousal, which has been associated with burnout. Mediation
Conclusions
The present study would appear to be the first study to assess the JD-R model using physiological indices of stress, potentially an important step in the development of this model. Additionally, our findings suggest that assessments of psychological stress or physiology in isolation are not as useful as looking at both in combination. Measurements of the sAA-AR as a surrogate biomarker of ANS dysregulation may prove to be an important tool in identifying both the magnitude of the burnout
Source of funding and conflicts of interest
KL was supported by an Australian Government Research Training Program Scholarship. This research was supported from funding from the Sport, Exercise and Rehabilitation Research Focus Area, La Trobe University. The authors report no conflict of interest.
References (66)
- et al.
Biomarkers in burnout: a systematic review
J. Psychosom. Res.
(2011) - et al.
Cortisol awakening response and psychosocial factors: a systematic review and meta-analysis
Biol. Psychol.
(2009) - et al.
The cortisol awakening response (CAR): facts and future directions
Int. J. Psychophysiol.
(2009) - et al.
Determinants of salivary α-amylase in humans and methodological considerations
Psychoneuroendocrinology
(2009) - et al.
Human salivary alpha-amylase reactivity in a psychosocial stress paradigm
Int. J. Psychophysiol.
(2005) - et al.
Simultaneous measurement of salivary cortisol and alpha-amylase: Application and recommendations
Neurosci. Biobehav. Rev.
(2017) - et al.
Modulation of attentional inhibition by norepinephrine and cortisol after psychological stress
Int. J. Psychophysiol.
(2000) - et al.
Associations between the awakening responses of salivary α-amylase and cortisol with self-report indicators of health and wellbeing among educators
Teach. Teach. Educ.
(2016) - et al.
The diurnal course of salivary alpha-amylase in nurses: an investigation of potential confounders and associations with stress
Biol. Psychol.
(2010) - et al.
The salivary alpha amylase over cortisol ratio as a marker to assess dysregulations of the stress systems
Physiol. Behav.
(2012)