Sitting cross-legged for 30 min alters lower limb shear stress pattern but not flow-mediated dilation or arterial stiffness

Tremblay, Joshua C.; Stimpson, Taylor V.; Murray, Kristen; Pyke, Kyra E.

doi:10.1139/apnm-2018-0339

Cited by 6 publications

(9 citation statements)

References 18 publications

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“…However, due to recent growing evidence showing the potential detrimental effects, prolonged sitting may now be considered as the experimental condition. Further, because this study aimed to evaluate the effects of a simulated workday of prolonged sitting, participants were only instructed to remain seated without any further restrictions on their lower limb motion or mode (i.e., not instructed to avoid fidgeting or leg crossing), which could have affected cardiovascular responses [37, 49].…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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“…The population and design of each study are reported in Supplementary Table 1 (see Table, Supplemental Digital Content, Appendix, http://links.lww.com/MSS/C407). From the 31 studies included in the analyses, vascular function was assessed in a total of 484 participants: healthy, 322 (9,10,17,18,20–26,36–49); overweight or obesity, 121 (7,50–52); metabolic syndrome, 5 (53); and T2D, 36 (42,54). No participants from any of the included studies were described as having impaired fasting glucose or impaired glucose tolerance.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…Bouts of prolonged sitting ranged from 0.5 h (44,46) to 8.5 h (54), with the median duration of 3.0 h. The majority of study protocols assessed the effect of prolonged sitting on vascular function; however, three studies utilized prolonged laying down (44,47,50) and two studies used undefined sedentary behavior (40,52). Assessments of FMD were mostly performed in the supine position (9,10,18,20–23,26,37,39,41,42,44,46–51), with only eight studies performing (49) FMD in the seated position (7,17,24,25,38,45,53,54) and one study in a semirecumbent position (36). Vascular function was predominantly assessed in the lower limb ( n = 23; superficial femoral artery, 8 studies [7,17,18,24,25,38,46,54]; popliteal artery, 14 studies [9,10,20–23,26,36,43,45,47–49,51]; posterior tibial artery, 1 study [41]), with only 12 trials assessing the brachial artery (7,23,25,37,39,40,42–44,50,52,53).…”

Section: Resultsmentioning

confidence: 99%

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The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis

Taylor

Pinto

Maniar

et al. 2021

Medicine &Amp; Science in Sports &Amp; Exercise

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Objective: This study aimed to determine the dose-response relationship between prolonged sitting and vascular function in healthy individuals and those with metabolic disturbances and to investigate the acute effects, on vascular function, of interventions that target interrupting prolonged sitting. Design: This is a systematic review with meta-analysis. Data Sources: Ovid Embase, Ovid Medline, PubMed, and CINAHL were searched from inception to 4 December 2020. Eligibility Criteria: Randomized crossover trials, quasi-randomized trials, and parallel group trials where vascular function (flow-mediated dilation [FMD]) was assessed before and after an acute period of sedentary behavior was used in this study. Results: Prolonged sitting resulted in a significant decrease in the standardized mean change (SMC) for lower-limb FMD at the 120-min (SMC = −0.85, 95% confidence interval [CI] = −1.32 to −0.38) and 180-min (SMC = −1.18, 95% CI = −1.69 to −0.66) time points. A similar pattern was observed for lower-limb shear rate. No significant changes were observed for any outcomes in the upper limb. Subgroup analysis indicated that prolonged sitting decreased lower-limb FMD in healthy adults (SMC = −1.33, 95% CI = −1.89 to −0.78) who had higher a priori vascular endothelial function, but not in those with metabolic and vascular dysfunction (SMC = −0.51, 95% CI = −1.18 to 0.15). Interrupting sitting with active interruptions increased the standardized mean difference for FMD, relative to prolonged sitting, but it was not statistically significant (0.13, 95% CI = −0.20 to 0.45). Conclusions: Lower-limb vascular function is progressively impaired as a consequence of prolonged sitting, up to 180 min. A similar trend was not observed in upper-limb vascular function. Subgroup analysis indicated that prolonged sitting negatively affects healthy populations, a finding not observed in those with metabolic disturbances. Regularly interrupting sitting with activity may be beneficial for those with metabolic disturbances.

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“…These sitting-induced effects on PWV have been reported in young healthy adults (Evans et al, 2019), overweight/obese adults (Credeur et al, 2019) and middle-aged at-risk adults (overweight/obese, hypertensive) (Alansare et al, 2020), highlighting that sitting can have broader effects on vascular health beyond lower limb arterial function. However, similar to FMD findings, there are inconsistencies across the literature with some studies reporting that PWV remains unaltered following uninterrupted prolonged sitting (Kowalsky et al, 2019;Perdomo et al, 2019;Tremblay et al, 2019;Caldwell et al, 2020;Headid et al, 2020). Nevertheless, while such studies fail to show any acute change in PWV that reached the clinically significant threshold of 1 m•s −1 (corresponding to an increased risk of 14% and 15% in cardiovascular events and all-cause mortality, respectively) (Vlachopoulos et al, 2010), it is plausible to consider that repeated prolonged periods of sitting may aggravate aortic stiffness in the long-term.…”

Section: Arterial Stiffnessmentioning

confidence: 93%

Detrimental effects of physical inactivity on peripheral and brain vasculature in humans: Insights into mechanisms, long-term health consequences and protective strategies

Daniele

Lucas²,

Rendeiro³

2022

Front. Physiol.

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The growing prevalence of physical inactivity in the population highlights the urgent need for a more comprehensive understanding of how sedentary behaviour affects health, the mechanisms involved and what strategies are effective in counteracting its negative effects. Physical inactivity is an independent risk factor for different pathologies including atherosclerosis, hypertension and cardiovascular disease. It is known to progressively lead to reduced life expectancy and quality of life, and it is the fourth leading risk factor for mortality worldwide. Recent evidence indicates that uninterrupted prolonged sitting and short-term inactivity periods impair endothelial function (measured by flow-mediated dilation) and induce arterial structural alterations, predominantly in the lower body vasculature. Similar effects may occur in the cerebral vasculature, with recent evidence showing impairments in cerebral blood flow following prolonged sitting. The precise molecular and physiological mechanisms underlying inactivity-induced vascular dysfunction in humans are yet to be fully established, although evidence to date indicates that it may involve modulation of shear stress, inflammatory and vascular biomarkers. Despite the steady increase in sedentarism in our societies, only a few intervention strategies have been investigated for their efficacy in counteracting the associated vascular impairments. The current review provides a comprehensive overview of the evidence linking acute and short-term physical inactivity to detrimental effects on peripheral, central and cerebral vascular health in humans. We further examine the underlying molecular and physiological mechanisms and attempt to link these to long-term consequences for cardiovascular health. Finally, we summarize and discuss the efficacy of lifestyle interventions in offsetting the negative consequences of physical inactivity.

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Sitting cross-legged for 30 min alters lower limb shear stress pattern but not flow-mediated dilation or arterial stiffness

Cited by 6 publications

References 18 publications

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

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

The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis

Detrimental effects of physical inactivity on peripheral and brain vasculature in humans: Insights into mechanisms, long-term health consequences and protective strategies

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