Influence of Permanent Night Work on the Circadian Rhythm of Blood Pressure

Night workers exercise their labours activities and rest in contrary schedules to the chronobiological standards. This inversion leads the body to several adaptations, including changes in the circadian rhythm of blood pressure (BP). Objectives To evaluate the BP in individuals who perform work at night, in order to objectively detail the BP circadian rhythm adaptations infixed night workers. Methods A cross-sectional study enrolling 23 fixed night workers, both genders, was performed, with 24 h BP measured with ambulatory blood pressure monitoring (ABPM) during a normal working day. Risk factors, anthropometric and lifestyle information were collected using a standard questionnaire. Results Ambulatory BP demonstrated a pattern of adaptation to the sleep/activity cycle in all participants. BP dropped during the sleeping period (mean drop: −11.35 ± 6.85) and was higher during the awakening period, reaching the highest results and greater BP variability during the working period. The chronobiological adaptation of the 24 h BP was not dependent on sociodemographic or clinical characteristics. In addition, age, male gender, obesity, and those working less time were associated with higher BP mean values. Conclusions The circadian rhythm of BP follows the working circadian profile of the individual.