When the SAM- and HPA-axes are repeatedly activated during stressful situations — at work and/or at home — they exert a pathophysiological strain on the individual. This maladaptive process is referred to as allostatic load (McEwen and Stellar, 1993). Because burnout remains an ill understood condition that is often treated like depression, evidence-based approaches and technologies that disentangle them are needed. We believe that the development of AL algorithms might be extremely beneficial for healthcare providers that are not currently equipped to prevent, detect, or even accurately diagnose burnout. As chronic stress at work contributes to both depression and burnout, it follows that measuring AL along with stress hormone dynamics might help differentiate these and other diseases. In addition to being an integral product of stress responses and a key mediator leading to AL, cortisol follows a normal diurnal rhythm necessary for proper functioning. A normal circadian profile consists of an acute increase during the first hour after awakening (Federenko et al., 2004; Pruessner et al., 1997), followed by gradual decreases throughout the day. The awakening cortisol response (ACR) is used as a robust marker of HPA-axis integrity and is very sensitive to psychological stress (Schulz et al., 1998). In a recent meta-analysis of 62 articles, it was found that the magnitude of the ACR is positively associated with job stress and general life stress, but negatively associated with fatigue, burnout, and exhaustion (Chida and Steptoe, 2009). Indeed, hypocortisolism is a phenomenon that occurs in approximately 20—25% of patients suffering from stress-related diseases like chronic fatigue syndrome, fibromyalgia, PTSD, burnout, and atypical depression to name a few (for a review, see Fries et al., 2005).


"Chronic stress causes stress hormones to strain many biological systems in a process referred to as allostatic load (AL) that is measurable using an index of biomarkers. While the AL framework has been successfully applied in studies of workplace stress, few studies have investigated burnout, a debilitating condition sometimes characterized by blunted stress hormone levels. Using an AL index based on clinical norms, we hypothesized that higher AL indices would be associated with increased chronic stress, burnout symptoms, as well as hypoactive diurnal and reactive stress hormone levels. Fifteen neuroendocrine, immune, metabolic, and cardiovascular biomarkers were collected for 30 healthy participants from various professions and values were transformed into an AL index using clinical norms. Stress reactivity was assessed for salivary cortisol and α-amylase levels in response to the Trier Social Stress Test. Diurnal cortisol was measured at five time points (awakening, 30 min after awakening, 14:00 h, 16:00 h, and before bedtime) over two working days. We also administered questionnaires of chronic stress, burnout, and depression. Our results demonstrate that increased AL is associated with increased chronic stress, burnout symptoms, but not depressive symptoms. The High AL group demonstrated lower morning and stress reactive cortisol levels in comparison to the Low AL group, but no significant effects were detected for salivary α-amylase. These findings provide preliminary support for the utility of a new clinical AL index that is sensitive to physiological recalibrations intermittently observed in burnout research.
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