The evidence concerning how posture influences blood pressure is not consistent. The aim of this cross-sectional study was to consider the clinical and epidemiological implications of blood pressure measured in seated versus supine position, and to investigate the impact of age, sex, body mass index (BMI), and diabetes on these differences.
This study included 1298 individuals (mean age 58.6 ± 11.8 years) from the Vara-Skövde cohort at the 10 years’ follow-up visit in 2014. Physical examination included blood pressure measurements in seated and supine position. Self-reported information on diabetes status, hypertension, ongoing medication, leisure time physical activity, and smoking habits were obtained. Linear regression models accounted for differences in age, sex, BMI, and known diabetes.
Both systolic and diastolic blood pressure were significantly higher in the seated position [1.2 mm Hg, P < .001, 95% confidence interval (95% CI) 0.79–1.54 and 4.2 mm Hg, P < .001, 95% CI 4.08–4.71, respectively]. The prevalence of high blood pressure in seated position was higher (19.9%) than in supine position (13.5%). Linear regression analysis showed that age (β = −0.215, P < .001) and diabetes (β = −0.072, P = .012) were associated with smaller differences in postural diastolic blood pressure and BMI (β = 0.124, P < .001) with greater difference.
This study showed substantial postural differences in blood pressures measured in office. Measuring blood pressure in the supine position shows lower blood pressure readings when compared with the seated position. Clinicians should be aware of how age, BMI, and diabetes influence these differences.