Association of Device-Measured Habitual Sedentary Activity and Standing Posture With Blood Pressure and Hypertension in Danish Adults: The Lolland-Falster Health Study.

Background: Limited evidence exists on the link between sedentary activity and blood pressure (BP), especially using combined thigh- and back-worn accelerometry, which offers accurate posture classification. This study examined the association between device-measured sedentary activity patterns and BP levels and hypertension and explored whether obesity explained these associations.

Methods: This cross-sectional study included 3127 adults (≥18 years) from the Danish Lolland-Falster Health Study (2017-2020). The outcome was participants' systolic BP and diastolic BP in mm Hg measured by a health care professional. Exposure was time spent on sedentary activity (duration, postures, prolonged bouts and breaks in sedentary activity) during the day assessed with thigh-worn and back-worn accelerometers. Multiple regression models were used to investigate if sedentary activity was associated with BP levels.

Results: Participants with hypertension, standardized for age and sex, were more sedentary (9.4 hours/day), had fewer sedentary breaks (54 breaks/day), and more prolonged sedentary bouts (5 bouts/day) compared with those without hypertension. Daily number of sedentary breaks between ≥50 to <65 and ≥65 was associated with lower systolic BP (-1.8 mm Hg [95% CI, -3.3 to -0.3] and -2.3 mm Hg, [95% CI, -3.8 to -0.7]) when compared with participants with daily breaks <50. Higher total daily sedentary time was associated with higher diastolic BP (0.3 mm Hg per hours/day [95% CI, 0.05-0.5]).

Conclusions: Higher total sedentary time and prolonged sedentary bouts were associated with higher diastolic BP, independent of lifestyle factors. Conversely, a higher number of sedentary breaks was associated with lower systolic BP, diastolic BP, and lower odds of hypertension.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02482896.