Differences in brachial and femoral artery responses to prolonged sitting

Thosar, Saurabh S.; Bielko, Sylvanna L.; Wiggins, Chad C.; Wallace, Janet P.

doi:10.1186/1476-7120-12-50

Cited by 62 publications

(112 citation statements)

References 30 publications

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“…Our previous findings (19,20) and findings from others (15,26) that sitting causes endothelial dysfunction in the leg, but not the arm, fuel the idea that increased susceptibility of the leg vasculature to atherosclerosis may be, in part, attributable to the direct detrimental effects of prolonged sitting on that vasculature. Strategies such as fidgeting can offset the decay in leg blood flow and shear stress during sitting, thus preventing the consequent impairment of endothelial function and potentially providing important vascular benefits in the long term.…”

Section: Discussionsupporting

confidence: 59%

Prolonged sitting-induced leg endothelial dysfunction is prevented by fidgeting

Morishima

Restaino

Walsh

et al. 2016

American Journal of Physiology-Heart and Circulatory Physiology

130

145

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Prolonged sitting impairs endothelial function in the leg vasculature, and this impairment is thought to be largely mediated by a sustained reduction in blood flow-induced shear stress. Indeed, preventing the marked reduction of shear stress during sitting with local heating abolishes the impairment in popliteal artery endothelial function. Herein, we tested the hypothesis that sitting-induced reductions in shear stress and ensuing endothelial dysfunction would be prevented by periodic leg movement, or "fidgeting." In 11 young, healthy subjects, bilateral measurements of popliteal artery flow-mediated dilation (FMD) were performed before and after a 3-h sitting period during which one leg was subjected to intermittent fidgeting (1 min on/4 min off) while the contralateral leg remained still throughout and served as an internal control. Fidgeting produced a pronounced increase in popliteal artery blood flow and shear rate (prefidgeting, 33.7 Ϯ 2.6 s Ϫ1 to immediately postfidgeting, 222.7 Ϯ 28.3 s Ϫ1; mean Ϯ SE; P Ͻ 0.001) that tapered off during the following 60 s. Fidgeting did not alter popliteal artery blood flow and shear rate of the contralateral leg, which was subjected to a reduction in blood flow and shear rate throughout the sitting period (presit, 71.7 Ϯ 8.0 s Ϫ1 to 3-h sit, 20.2 Ϯ 2.9 s Ϫ1

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Section: Discussionsupporting

confidence: 59%

Prolonged sitting-induced leg endothelial dysfunction is prevented by fidgeting

Morishima

Restaino

Walsh

et al. 2016

American Journal of Physiology-Heart and Circulatory Physiology

130

145

View full text Add to dashboard Cite

show abstract

“…Indeed, although shear rate is reduced immediately upon sitting, in other studies the reduction in FMD was observed at 1, 3 and 6 h post-sitting (Restaino et al, 2015Thosar et al, 2014). (c) Ten minutes of sitting resulted in a reduction in mean popliteal artery blood flow that was sustained for 1 h. (d) In contrast to FMD, hyperaemic blood velocity AUC was significantly reduced after 10 min of sitting and remained reduced throughout recovery.…”

Section: Discussionmentioning

confidence: 85%

“…These studies have demonstrated that 1-6 h of uninterrupted sitting results in impairments in leg macrovascular function as assessed by flowmediated dilatation (FMD) and microvascular function as assessed by reactive hyperaemia (Restaino, Holwerda, Credeur, Fadel, & Padilla, 2015;Thosar, Bielko, Wiggins, & Wallace, 2014). These studies have demonstrated that 1-6 h of uninterrupted sitting results in impairments in leg macrovascular function as assessed by flowmediated dilatation (FMD) and microvascular function as assessed by reactive hyperaemia (Restaino, Holwerda, Credeur, Fadel, & Padilla, 2015;Thosar, Bielko, Wiggins, & Wallace, 2014).…”

Section: Introductionmentioning

confidence: 99%

Brief periods of inactivity reduce leg microvascular, but not macrovascular, function in healthy young men

Vranish

Young

Stephens

et al. 2018

Experimental Physiology

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Prolonged sitting for 1-6 h has been shown to impair leg macrovascular [i.e. reduced flow-mediated dilatation (FMD)] and microvascular (i.e. reduced reactive hyperaemia) function. These impairments appear to be mediated through reductions in shear stress. Interestingly, a reduction in shear rate has been observed as early as 10 min into sitting. However, it is unknown whether this acute reduction in shear stress is sufficient to affect vascular function. Accordingly, we studied 18 young men and assessed popliteal artery FMD and reactive hyperaemia before (Baseline) and after (PostSit) a 10 min sitting period. Popliteal artery shear rate was significantly reduced during sitting (Baseline, 62 ± 35 s ; 10 min sitting, 27 ± 13 s ; P < 0.001). Macrovascular function was unaffected by 10 min of sitting (Baseline, 4.4 ± 2.1%; PostSit, 4.3 ± 2.3%; P = 0.97), but microvascular function was reduced (Baseline, 4852 ± 2261 a.u.; PostSit, 3522 ± 1872 a.u.; P = 0.02). In a subset of individuals, we extended the recovery period after sitting and demonstrated that resting shear rate and reactive hyperaemia responses remained low up to 1 h post-sitting (P < 0.001), whereas FMD was unchanged throughout (P = 0.99). Additionally, time control experiments were performed with participants in an immobile supine position, which demonstrated no change in macrovascular function (P = 0.94) but, unexpectedly, a reduction in microvascular function (P = 0.008). Importantly, when calf muscle contractions were performed during supine rest, reactive hyperaemia responses were maintained (P = 0.76), along with FMD (P = 0.88). These findings suggest that the leg microcirculation might be more vulnerable to short periods of inactivity, whereas conduit artery vasodilatation appears well maintained. Moreover, intermittent skeletal muscle contractions are beneficial for microvascular function.

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“…Moreover, prolonged sitting may impair endothelial function and increase vascular oxidative stress . Blood viscosity might be an alternative mechanism for endothelial dysfunction during sitting, which has been positively associated with increased coagulation and inflammatory markers . Further mechanistic studies are needed to understand why prolonged sitting is associated with increased risk of LUTS.…”

Section: Discussionmentioning

confidence: 99%