| Summary: | High cardiovascular and cortisol reactivity to stressful tasks are predictors of increased future cardiovascular risk. Few studies have investigated the impact of shift work on cardiovascular reactivity, and none have examined cortisol reactivity. The purpose of this study was to compare cardiovascular and cortisol stress reactivity in female shift workers (SW) versus non-shift workers (NSW). Nineteen SW (40 ± 11 years) and 19 NSW (42 ± 11 years) participated. Heart rate, systolic blood pressure, and diastolic blood pressure (DBP) were measured at rest, and during each minute of a speech (5 min) and mental arithmetic (5 min) stress task. Serum cortisol was measured pre- and poststress task (immediately and 15 min post). Values are means ± SD . Peak increases in DBP during the task did not differ between groups ( p = .261), however, analyzed over time there was an interaction such that DBP increased significantly more in SW during the fifth minute of the speech task ( p = .035). There were no group differences in heart rate or systolic blood pressure responses. The increase in cortisol also did not differ between groups (ΔSW: 5.5 ± 7.5 µg/dL, ΔNSW: 1.8 ± 2.9 µg/dL, p = .165). However, when compared separately, the increase in cortisol from baseline to peak poststress was significant in SW ( p = .013) but not in NSW ( p = .125). In conclusion, these preliminary data suggest that shift work exposure may have a modest influence on cardiovascular and cortisol reactivity. Further research is necessary to fully characterize and explore the importance of stress reactivity in this population.
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