Local exercise does not prevent the aortic stiffening response to acute prolonged sitting: a randomized crossover trial

Abstract

Prolonged sitting has been shown to promote endothelial dysfunction in the lower legs. Furthermore, it has been reported that simple sitting-interruption strategies, including calf raises, prevent leg endothelial dysfunction. However, it is unclear whether prolonged sitting affects central cardiovascular health, or whether simple sitting-interruption strategies prevent impaired central cardiovascular health. This study sought to answer two questions: in young, healthy adults 1) does prolonged sitting (3 h) lead to increased aortic stiffness, and 2) do intermittent calf raise exercises to prevent pooling prevent aortic stiffening. Twenty young, healthy participants (21.7 ± 2.5 yr, 70% female, 25.5 ± 6.1 kg/m2) were randomized to 3 h of sitting with (CALF) or without (CON) 10 calf raises every 10 min. Aortic stiffening [carotid-femoral pulse wave velocity (PWV)] was measured in the supine position pre- and post-sitting. Venous pooling during sitting was estimated with total hemoglobin (tHB) concentration using near-infrared spectroscopy. There were no condition × time interactions. Following 3 h of sitting, PWV significantly increased (0.30 ± 0.46 m/s, P < 0.001). There was no condition effect for PWV ( P = 0.694), indicating the intermittent calf rises did not preserve central cardiovascular health. tHb was not significantly affected by sitting ( P = 0.446) but was 1.9 μM higher for CON versus CALF ( P = 0.106). Sitting increases aortic stiffness in young, healthy individuals, a process that may be influenced by lower extremity blood pooling. Calf raises, which have been reported to preserve vascular function in the legs, do not appear to provide sufficient stimulus for maintaining central cardiovascular health. NEW & NOTEWORTHY Although simple strategies, such as fidgeting or calf raises, are sufficient for preserving vascular function in the legs, data from the current study indicate that such strategies are not sufficient for maintaining central cardiovascular health, which is linked to cardiovascular disease.

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

“…In both studies, the investigators also reported significant elevation in cfPWV following prolonged sitting. Chronic exposure to prolonged sitting and resulting acute elevations in PWV, similar to the increases observed in Credeur et al [8], Evans et al [13], and our study, could be detrimental to cardiovascular health long term. In the current study, though cfPWV (central) and caPWV (peripheral lower extremity) increased in response to prolonged sitting when measured in a supine posture, crPWV (the peripheral upper extremity) did not significantly increase.…”

“…When measured using current recommendations of a supine posture [24], a simulated workday of prolonged sitting significantly increased supine cfPWV (0.52 ± 0.20 m/s) and caPWV (0.38 ± 0.16 m/s) over time in participants with elevated BP and overweight/obesity. We are aware of only 2 other studies that assessed the effect of 3 h of prolonged sitting on cfPWV [8, 13]. In both studies, the investigators also reported significant elevation in cfPWV following prolonged sitting.…”

“…Several studies have evaluated acute cardiovascular responses, such as blood pressure (BP), across various durations (i.e., 2, 3, 7, and 8 h) of prolonged sitting [7-12]. Recently, a handful of studies have also measured the effects of prolonged sitting on pulse wave velocity (PWV) [8, 10, 13], a subclinical vascular measure where acute increases likely reflect adverse changes in vascular function such as increases in smooth muscle tone [7-10, 14, 15]. Yet, findings from these studies are not consistent in that some, but not all, report that BP, PWV, or both increase following prolonged sitting [7-10, 12, 14].…”

Sitting decreases endothelial microparticles but not circulating angiogenic cells irrespective of lower leg exercises: a randomized cross‐over trial

“…Interestingly, we found that arterial stiffening persisted regardless of intermittent activity (periodic calf raises) used to disrupt blood pooling during 3 h of acute sitting (Credeur et al, 2019;Evans et al, 2019).…”

“…CD34 + CAC gene expression of CXCR4and VEGFR2 (markers of homing and angiogenesis), and plasma ET-1 levels were unchanged as well. Finally, calf raises designed to attenuate blood pooling in the lower extremities(Evans et al, 2019) had no effect on any measured circulating factors. These findings suggest that acute bouts of prolonged sitting may reduce markers of endothelial activation and apoptosis independent of changes in shear rate due to calf raises, and highlight the need for future studies including supine controls and functional assessments of MP cargo such as micro-RNAs, mRNA and proteins.…”