The Effects of a Simulated Workday of Prolonged Sitting on Seated versus Supine Blood Pressure and Pulse Wave Velocity in Adults with Overweight/Obesity and Elevated Blood Pressure

Abstract

We evaluated the effects of a simulated workday of prolonged sitting on blood pressure (BP) and pulse wave velocity (PWV) and examined whether posture (seated vs. supine) affected responses. Participants (n = 25) were adults, with overweight/obesity and elevated BP, and performed seated desk work for 7.5 h. BP and PWV were measured in seated and supine postures at baseline (7:15 a.m.), midday (12:05 p.m.), and afternoon (4:45 p.m.). Generalized linear mixed models evaluated the effects of prolonged sitting on BP and PWV within each posture and interactions by posture and sex. In the recommended postures, seated BP and supine carotid-femoral pulse wave velocity (cfPWV) and carotid-ankle pulse wave velocity (caPWV), but not carotid-radial pulse wave velocity (crPWV), significantly increased over the simulated seated workday (all p < 0.05; effect sizes [d] ranged from 0.25 to 0.44). Whilst no posture-by-time interactions were observed (p > 0.05), BP, caPWV, and crPWV were higher when seated versus supine (main effects of posture p < 0.05; d ranged from 0.30 to 1.04). Exploratory analysis revealed that females had greater seated BP responses (p for interaction <0.05); seated PWV and supine BP and PWV responses were similar by sex (p for interaction >0.05). A simulated workday of prolonged sitting increased seated BP and supine cfPWV and caPWV, and posture minimally influenced these responses. These results add to the evidence suggesting a deleterious effect of prolonged sitting on cardiovascular health.

Keywords: Blood pressure; Desk work; Heart rate; Posture; Prolonged sitting; Pulse wave velocity.

Fig. 1.

Experimental protocol. All participants reported to the laboratory between 7:00 and 7:30AM. BP and PWV, respectively, were measured three times (morning, mid-day, and afternoon) in a seated posture followed by supine. Standardized meals were consumed immediately after morning and afternoon assessments. Then, participants begun their morning and afternoon prolonged sitting sessions (3 hour 40 minutes per session) during which they performed self-provided desk work and were allowed to take necessary restroom breaks.

Fig. 2.

BP and HR responses to prolonged sitting in a seated vs. supine posture. Generalized linear mixed (GLM) models examined the main effects of time, posture, and their interaction on BP and HR responses. β coefficients represent change in BP or HR over the entire experiment (main effect of time), differences in BP or HR comparing sitting to supine (main effect of posture), and their interaction. Abbreviations: d: Cohen’s d; DBP: diastolic blood pressure; HR: heart rate; MAP: mean arterial pressure; SBP: systolic blood pressure; SE: standard error. Bold indicates significant effect (p < 0.05)

Fig. 3.

PWV responses to prolonged sitting in seated vs. a supine posture. Generalized linear mixed (GLM) models examined the main effects of time, posture, and their interaction on PWV responses. β coefficients represent change in PWV over the entire experiment (main effect of time), differences in PWV comparing sitting to standing (main effect of posture), and their interaction. Abbreviations: caPWV: carotid-ankle pulse wave velocity; cfPWV: carotid-femoral pulse wave velocity; crPWV: carotid-radial pulse wave velocity; d: Cohen’s d; SE: standard error. Bold indicates significant effect (p < 0.05).