Relationship Between Orthostatic Blood Pressure Changes and Postural Sway When Standing up from a Chair in Older Adult Females

Abstract

Orthostatic reductions in blood pressure upon standing are common among the elderly. This orthostatic blood pressure changes may relate to the augmentation of postural sway and may be an important risk factor for falls. Thus, to clarify whether orthostatic blood pressure change on standing up from a chair is relevant to postural sway, we simultaneously measured changes in blood pressure and the movement of a weighted center upon standing. A total of 63 older adult females were investigated. Blood pressure [systolic blood pressure (SBP), diastolic BP] measured in a sitting position were defined as the baseline levels. The movement of center of pressure (COP) was measured using a stable force platform to quantify postural stability. Participants were instructed to stand up from a chair on the platform and maintain an upright position with their eyes open for 40 seconds. Upon standing, the participant’s blood pressure and the movement of COP were recorded. Pearson’s correlation was performed to determine relationships between the changes in BP and the movement of COP [distance of the movement of COP (LNG), envelopment area traced by the movement of COP (AREA)]. SBP was reduced while maintaining an upright position for 40 seconds (–5.0 ± 8.6 mmHg), but not diastolic BP (0.6 ± 4.3 mmHg). Moreover, the change in SBP showed a negative relationship with LNG ( r = –0.43, p < 0.01) and AREA ( r = –0.31, p < 0.05). These results suggested that postural change influenced SBP, and that the drop of SBP was associated with augmentation of postural instability in older adult females.