Cortisol secretory activity in older people in relation to positive and negative well-being

Secretion of the hormone cortisol, a physiological correlate of affect, has been studied mostly in relation to negative states, especially stress. By contrast, policy initiatives aimed at older populations now routinely emphasise well-being and a 'positive ageing' perspective. In this study, we examined diurnal salivary cortisol profiles from 50 active seniors recruited into a wider community research project (mean age 74 years; 34 F/16 M). Participants' wrist activity was continuously monitored by actimeters in their homes over a 48 h period. During this time two diurnal cycles of cortisol data were collected (8 samples per day); with actimeter data providing a compliance check in regard to timing of self-administered saliva collections. Prior to the trial, participants had completed the GHQ-30 which was scored separately to yield both positive and negative well-being scores which matched closely normative data from over 6000 cases in a large survey. Our data suggest that positive and negative psychological well-being are quite strongly and inversely correlated. However, neither on their own was associated with basal levels of cortisol. Rather, for cortisol secretion in the 45-min period following awakening, but not during the rest of the day, we found a significant interaction between positive and negative well-being (p<0.024). Further analysis of this interaction showed that among participants low on negative well-being, higher positive well-being was significantly associated with lower cortisol; equally, among participants high on positive well-being, lower negative well-being was significantly associated with lower cortisol. Thus, a powerful synergy seemed to be operating in this early morning period such that cortisol secretion was 27% lower in participants with both higher-than-average positive well-being and lower-than-average negative well-being (comprising 34% of the sample). We conclude that cortisol secretion in the first 45 min following awakening is distinct from the rest of the day and most able to discriminate well-being states.