**2.1 Cortisol**

*Occupational Wellbeing*

stress. As occupational duties and stress exposure varies across occupations, occupational stress sources (i.e., stressors) can be further separated into operational stressors (i.e., job content-inherent aspects of the occupation) and organizational stressors (i.e., job context-characteristics and behaviors of the organization and people of them) [7]. One route to understand how different levels of occupational stress can affect the body is by looking to varying levels of occupational risk exposure

Researchers have specialized in examining the effects of occupational responsibilities [7–9], comparing risk subtypes within a high-risk occupation [10]. In a previous study [10], the authors focused on identifying the objective physiological stress associated with risk-subtype among police officers in comparison to the general public. This prior literature revealed that police had significantly higher physiological stress responses (i.e., basal cortisol regulation) in comparison to the general population, with the effect even more pronounced as objective occupational

The goal of this chapter is to discuss stress of varying occupational risk profiles and objective hazards' impact on physiological stress response, while considering participants' subjective reports of stress. Specifically, the authors present analyses to assess subjective measures of stress to further stratify and identify specific factors that may drive objective physiological stress (i.e., basal cortisol regulation) trends observed in a police sample. We hypothesized a positive association between increased risk associated with objective occupational hazards and self-reported stressors. Specifically, that dysregulation in HPA function would be higher among tactical unit officers and this would align with both increased occupational hazards

within a single occupation via its operational stressors.

hazards increased (i.e., frontline vs. tactical police).

**2. The "fight-or-flight" response**

(objective) and self-reported occupational stressors (subjective).

response when a threat is presented or removed, respectively.

Evolutionarily speaking, stress and our ability to respond to it is adaptive and essential for our survival. When presented with a potential threat, the body automatically engages in a series of adaptive physiological processes to maximize survival [11]. Colloquially this process is known as the "fight-or-flight" response. During fight-or-flight, the autonomic nervous system's (ANS) two sub-systems are engaged: the sympathetic nervous system (SNS) is activated, and the parasympathetic nervous system (PNS—responsible for calming and stabilizing the body) is suppressed. The Hypothalamic–Pituitary–Adrenal (HPA) axis is a critical system, producing a cascade of hormones that both maintain and dampen the fight-or-flight

While fight-or-flight is strictly a physiological response, it can be maintained and stimulated by psychological processes. The degree of activation among the SNS, PNS, and HPA axis is determined by an individual's perception of how threatening the stimulus is, and can be influenced by psychological factors (e.g., threat perception, anxiety, anticipation, perceived control over the situation, etc.) [12]. When a stimulus is perceived as stressful, the hypothalamus releases corticotropinreleasing hormone (CRH), which subsequently triggers the pituitary gland to release of adrenocorticotropic hormone (ACTH). ACTH travels in the bloodstream to the adrenal glands, located above the kidneys, triggering the release of stress hormones glucocorticoids (i.e., cortisol) and catecholamines (e.g., epinephrine, and

Stress hormones act upon the SNS and PNS, and higher priority survival functions such as heart rate, respiration, energy reserves, and short-term immunity are increased, while lower priority functions for threat response such as reproduction,

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norepinephrine) [13].

Cortisol (i.e., glucocorticoids) is a key regulating stress hormone in the human HPA axis cascade. Cortisol potentiates the effects of catecholamines on beta receptors (necessary for impacting peripheral receptors), suppresses immune function, and terminates the fight-or-flight response (via negative feedback loop) [15]. Cortisol is excreted in a dose–response manner to the level of perceived threat by the individual, meaning the greater the perceived threat, the more cortisol that is excreted [16].

Cortisol also has important regulatory functions outside times of stress; cortisol is additionally excreted in a systemic diurnal pattern over every 24-hour period cycle. Among healthy individuals, the diurnal pattern consists of higher levels upon waking, a significant peak around 30 minutes post-waking (i.e., the cortisol awakening response—CAR), steady decline throughout the day, and reaches its lowest point in the middle of the night before again elevating again in the early hours of the next day [17].
