Does cellular aging relate to patterns of allostasis? An examination of basal and stress reactive HPA axis activity and telomere length.

Long-term exposure to stress and its physiological mediators, in particular cortisol, may lead to impaired telomere maintenance. In this study, we examine if greater cortisol responses to an acute stressor and/or dysregulated patterns of daily cortisol secretion are associated with shorter telomere length. Twenty-three postmenopausal women comprising caregivers for dementia partners (n=14) and age- and BMI-matched non-caregivers provided home sampling of cortisol-saliva samples at waking, 30 min after waking, and bedtime, and a 12-hour overnight urine collection. They were also exposed to an acute laboratory stressor throughout which they provided saliva samples. Peripheral blood mononuclear cells were isolated from a fasting blood sample and assayed for telomere length. As hypothesized, greater cortisol responses to the acute stressor were associated with shorter telomeres, as were higher overnight urinary free cortisol levels and flatter daytime cortisol slopes. While robust physiological responses to acute stress serve important functions, the long-term consequences of frequent high stress reactivity may include accelerated telomere shortening.