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Background: Disrupted sleep quality is one of the proposed mechanisms through which chronic stress may lead to depression. However, there exist significant individual differences in sleep reactivity, which is the extent to which one experiences sleep disturbances in response to stress.Purpose: The aim of the current study was to investigate whether low high-frequency heart rate variability (HRV), as a psychophysiological marker of poor emotional and physiological arousal regulation, predicts stress-related sleep disturbances associated with greater risk of depression symptoms.Methods: Using a chronic caregiving stress model, 125 mothers of adolescents with developmental disorders and 97 mothers of typically developing adolescents had their resting HRV and HRV reactivity recorded and completed a measure of depressive symptoms, as well as a 7 day sleep diary to assess their sleep quality. A moderated mediation model tested whether sleep quality mediated the association between chronic stress exposure and depressive symptoms and whether HRV moderated this mediation.Results: After controlling for participant age, body mass index, ethnicity, socioeconomic status, and employment status, poor sleep quality mediated the association between chronic stress and depressive symptoms. Resting HRV moderated this indirect effect such that individuals with lower HRV were more likely to report poorer sleep quality in the context of chronic stressor exposure, which, in turn, was related to greater depressive symptoms.Conclusions: Lower HRV, a potential biomarker of increased sleep reactivity to stress, is associated with greater vulnerability to stress-related sleep disturbances, which, in turn, increases the risk for elevated depressive symptoms in response to chronic stress. [ABSTRACT FROM AUTHOR]

Many older adults experience chronic age-related stressors (e.g., life regrets or health problems) that are difficult to control and can disturb cortisol regulation. Self-compassion may buffer adverse effects of these stressful experiences on diurnal cortisol secretion in older adulthood. To examine whether self-compassion could benefit older adults’ cortisol secretion in the context of chronic and largely uncontrollable age-related stressors, 233 community-dwelling older adults reported their levels of self-compassion, age-related stressors (regret intensity, physical health problems, and functional disability), and relevant covariates. Diurnal cortisol was measured over 3 days and the average area-under-the-curve and slope were calculated. Higher levels of self-compassion were associated with lower daily cortisol levels among older adults who reported higher levels of regret intensity, physical health problems, or functional disability (βs < − .53, ps < .01), but not among their counterparts who reported lower levels of these age-related stressors (βs < .24, ps > .28). These results suggest that self-compassion may represent an important personal resource that could protect older adults from stress-related biological disturbances resulting from chronic and uncontrollable stressors. [ABSTRACT FROM AUTHOR]