Eveningness, depression and cardiovascular reactivity to acute psychological stress: a mediation model

The psychological pathways linking depression to blunted cardiovascular reactivity (CVR) are still being elucidated. The purpose of the present study was to test whether the association between eveningness, a diurnal/sleep-wake preference and CVR would be mediated by depressive symptoms. One hundred and eighty-two healthy young adults completed measures of morningness/eveningness (the Morningness-Eveningness Questionnaire; MEQ-SA), depressive symptoms (Hospital Anxiety and Depression Scale; HADS) and had their blood pressure and heart rate monitored throughout a standardised stress testing protocol. Results indicated that depressive symptoms were negatively associated with systolic blood pressure (SBP) but not diastolic blood pressure (DBP) or heart rate (HR) reactions to the stress task. Eveningness was also negatively associated with both SBP and DBP, but not HR. As such, those who reported increased depressive symptomology, and higher scores on eveningness displayed a more blunted cardiovascular response. Furthermore, the latter relationship was mediated by depressive symptoms such that those reporting higher scores on eveningness also reported increased depressive symptomology and this resulted in blunted CVR for SBP. These findings withstood adjustment for several confounding factors including time of testing. In conclusion, the present findings highlight the importance of considering eveningness when looking at the depression-blunted CVR relationship.