Evidence that Shift Work Influences the Relationship Between Reactivity to Mental Stress and Indices of Vascular Health: A Pilot Study

Abstract

High cardiovascular reactivity to stressful tasks is a predictor of increased future cardiovascular risk and may play a mechanistic role in disease progression. The purpose of this investigation was to examine the relationship between acute cardiovascular stress reactivity and indicators of vascular health status in shift workers (SW) and non‐shift workers (NSW). Female hospital employees were recruited. 18 NSW and 19 SW (minimum 6 yrs experience) participated. Blood pressure (Finometer), central pulse wave velocity (PWV) (carotid to femoral; applanation tonometry) and common carotid artery intima media thickness (IMT) (echo ultrasound) were assessed at rest. With continued blood pressure assessment, participants then completed a 20 min mental stress task with speech and arithmetic components (based on the Trier Social Stress Test). Systolic blood pressure (SBP) reactivity was quantified as the difference between the resting baseline SBP and the SBP during the stress task. Data are mean ± SD. SW and NSW did not differ with respect to age (42 ± 11 yrs, p=0.563), central PWV (6.6 ± 1.3 m/s, p=0.416), IMT (0.47 ± 0.11 cm, p=0.207) or SBP reactivity (20.3 ± 11.2 mmHg, p=0.717). In NSW there was no relationship between SBP reactivity and either PWV (p=0.789; r=0.07) or IMT (p=0.876; r=0.06). In contrast in SW, both PWV (p=0.032; r=0.507) and IMT (p=0.062; r=0.435) increased with increasing SBP reactivity. These data suggest that shift work experience may alter the relationship between cardiovascular stress reactivity and vascular health. Garfield Kelly Cardiovascular Research and Development fund, KGH.