A clinical allostatic load index is associated with burnout symptoms and hypocortisolemic profiles in healthy workers

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.