Background: Low back pain is one of the leading causes of disability globally and represents an enormous burden to aging adults. While multiple biological and psychosocial factors have been purported to play a role in back pain, dysregulation in stress responsivity has been touted as a potential etiological factor. Evidence suggests that negative psychological states can modulate biological stress responsivity in chronic pain; however, little is known regarding the influence of positive psychological factors in this relationship. 

Aims: The aim of this study was to examine the association between psychological risk and resilience factors with patterns of physiological stress reactivity and recovery in adults with low back pain. 

Method: Sixty adults (ages 60-93 years) completed measures of hope (Adult Dispositional Hope Scale), optimism (Life Orientation Test), pain catastrophizing (Pain Catastrophizing Scale), and perceived stress (Perceived Stress Scale), and then underwent a series of psychophysical pain testing procedures assessing responses to painful pressure, heat, and cold stimuli. Prior to pain induction, salivary samples were obtained at baseline and at seven time-points spanning 90 minutes after the end of pain testing. To examine reactivity and recovery profiles in hypothalamic-pituitary-adrenal (HPA) axis and Autonomic Nervous System (ANS) function, samples were assayed for cortisol and alpha-amylase.  

Results: Using two-piece multilevel growth curve models, findings revealed that perceived stress was significantly associated with cortisol reactivity, with lower levels of stress predicting larger increases in cortisol from baseline to peak levels (slope difference=-0.0027, p=0.01). Further, higher levels of hope and optimism were associated with increased cortisol reactivity (hope: slope difference=0.0043, p<.001; optimism: slope difference=0.0037, p=.001) and recovery (hope: slope difference=-0.001, p=.001; optimism: slope difference=-0.0011, p=.001). No significant differences in reactivity or recovery patterns emerged for alpha-amylase.  

Conclusion: Findings highlight the role of positive psychological resources in modulating physiological stress reactivity. Importantly, adaptive HPA responses to pain may serve as a pathway by which sources of psychological resilience positively influence the course and experience of pain.