Abstract P310: Effect of Static Stretching Exercise on Aortic Pulse Wave Velocity

Abstract

Introduction: Large-artery stiffness (i.e., aortic stiffness) is an independent predictor of hypertension which is a leading cause of excess cardiovascular morbidity and mortality. Carotid-femoral pulse wave velocity (cf-PWV) is considered the ‘gold-standard’ measure of arterial stiffness because it measures along the aorto-iliac pathway, which buffers blood pressure (BP) the most. While there is well-documented evidence on the health benefits of aerobic and resistance exercise, the information for the effect of stretching on aortic stiffness is limited. Previous studies have shown that arterial stiffness is associated with trunk flexibility. Stretching exercise targeted to improve flexibility may exert a beneficial effect on reducing aortic stiffness. Objectives: This study aimed to examine effects of a single bout of a structured static stretching exercise on aortic stiffness as well as trunk flexibility, blood pressure (BP), and heart rate (HR). Method: This study has a pretest-postest design without a control group. Thirty healthy women from the community were instructed to follow a video demonstration of a structured whole-body static stretching lasting 30 minutes. Each stretching was designed to improve range of motion and enhance flexibility in 10 body areas, and all stretching motions were performed in the sitting position. Aortic stiffness was measured by cf-PWV using the SphygmoCor system (AtCor medical, AU). Trunk Flexibility was measured by the sit and reach method. BP and HR were measured using the WelchAllyn Monitor (WelchAllyn, USA). Results: After stretching exercise, cf-PWV (m/s) was significantly reduced (M=6.93, SD=1.54 vs M=6.29, SD=1.17; t(29)=2.708, p =.011). In addition, HR (bpm) was significantly decreased (M=64.88, SD=6.29 vs M=61.77, SD=6.29; t(29) = 7.170, p=.000). A significant increase of lumbar flexibility (inches) was also detected (M=13.37, SD=4.3 vs M=16.45, SD=4.79; t(29) = 12.248, p=.000). Systolic BP and diastolic BP (mmHg) were decreased after stretching exercise from M=107.87 (SD 10.75) to M=106.82 (SD 12.48), from M=63.37 (SD 6.71) to M=61.88 (SD 6.47), respectively; however, the differences did not reach the statistical significance. Conclusions: Findings of the current study highlight the potential benefit of static stretching exercise on aortic stiffness independent of BP. The results also demonstrate that HR was significantly decreased after the stretching exercise. Given no sign of over-activity of sympathetic function, a structured static stretching exercise may be prescribed as an effective intervention to reduce aortic stiffness for the people with high risk of cardiac events. In addition, stretching motions that were conducted in the sitting position can be cautiously utilized as an effective intervention for stroke patients, post-surgery patients, and people who have unsteady walking.