Acute effects of sedentary breaks on vascular health in adults at risk for type 2 diabetes: A systematic review (original) (raw)
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PLOS ONE, 2021
The objective of this study was to compare acute effects of prolonged sitting, prolonged standing and sitting interrupted with regular activity breaks on vascular function and postprandial glucose metabolism. In a randomized cross-over trial, 18 adults completed: 1. Prolonged Sitting; 2. Prolonged Standing and 3. Sitting with 2-min walking (5 km/h, 10% incline) every 30 min (Regular Activity Breaks). Flow mediated dilation (FMD) was measured in the popliteal artery at baseline and 6 h. Popliteal artery hemodynamics, and postprandial plasma glucose and insulin were measured over 6 h. Neither raw nor allometrically-scaled FMD showed an intervention effect (p = 0.285 and 0.159 respectively). Compared to Prolonged Sitting, Regular Activity Breaks increased blood flow (overall effect of intervention p<0.001; difference = 80%; 95% CI 34 to 125%; p = 0.001) and net shear rate (overall effect of intervention p<0.001; difference = 72%; 95% CI 30 to 114%; p = 0.001) at 60 min. These differences were then maintained for the entire 6 h. Prolonged Standing increased blood flow at 60 min only (overall effect of intervention p<0.001; difference = 62%; 95% CI 28 to 97%; p = 0.001). Regular Activity Breaks decreased insulin incremental area under the curve (iAUC) when compared to both Prolonged Sitting (overall effect of intervention P = 0.001; difference = 28%; 95% CI 14 to 38%; p<0.01) and Prolonged Standing (difference = 19%; 95% CI 4 to 32%, p = 0.015). There was no intervention effect on glucose iAUC or total AUC (p = 0.254 and 0.450, respectively). In normal-weight participants, Regular Activity Breaks induce increases in blood flow, shear stress and improvements in postprandial metabolism that are associated with beneficial adaptations. Physical activity and sedentary behaviour messages should perhaps focus more on the importance of frequent movement rather than simply replacing sitting with standing.
Preventive Medicine Reports
The aim of this study was to investigate the associations of accelerometer-assessed sedentary time and breaks in sedentary time with 24-h events and duration of hypoglycaemia (< 3.9 mmol/l), euglycaemia (3.9-7.8 mmol/l), hyperglycaemia (> 7.8 mmol/l) and above target glucose (> 9 mmol/l). Thirty-seven participants with type 2 diabetes (age, 62.8 ± 10.5 years; body mass index, 29.6 ± 6.8 kg/m 2) in Glasgow, United Kingdom were enrolled between February 2016 and February 2017. Participants wore an activity monitor (activPAL3) recording the time and pattern of sedentary behaviour and a continuous glucose monitoring (CGM, Abbott FreeStyle Libre) for up to 14 days. Linear regression analyses were used to investigate the associations. Participants spent 3.7%, 64.7%, 32.1% and 19.2% of recording h/day in hypoglycaemia, euglycaemia, hyperglycaemia and above target, respectively. There was a negative association between sedentary time and time in euglycaemia (β = −0.44, 95% CI −0.86; −0.03, p = 0.04). There was a trend towards a positive association between sedentary time and time in hyperglycaemia (β = 0.36, 95% CI −0.05; 0.78, p = 0.08). Breaks in sedentary time was associated with higher time in euglycaemia (β = 0.38, 95% CI 0.00; 0.75, p = 0.04). To conclude, in individuals with type 2 diabetes, more time spent in unbroken and continuous sedentary behaviour was associated with poorer glucose control. Conversely, interrupting sedentary time with frequent breaks appears to improve glycaemic control. Therefore, this should be considered as a simple adjunct therapy to improve clinical outcomes in type 2 diabetes.
American Journal of Hypertension, 2015
BACKGROUND We previously reported increased moderate-intensity (3-6 metabolic equivalents (METs)) physical activity (PA) reverses aging-associated vascular endothelial dysfunction, a surrogate marker of cardiovascular risk. Whether reductions in sedentary time alone contribute to this improvement is unknown. METHODS Data from 96 adults (aged ≥50 years) enrolled in a randomized control trial evaluating a 12-week intervention to increase PA in sedentary individuals were analyzed. Amount and intensity of activity were measured pre-and post-intervention by step count and accelerometry. Subjects were divided into 3 categories based on change in sedentary activity (<1. 5 METs): (i) ≥5% reduction in sedentary time, (ii) 0-4.99% reduction, and (iii) increase sedentary time. Vascular endothelial function was measured by brachial artery flow-mediated dilation (FMD%) pre-and post-intervention. RESULTS Sedentary time decreased overall (P = 0.001), with a 101-minute decrease in category 1 (N = 27, P < 0.001), a 42-minute decrease in category 2 (N = 29, P = 0.003), and a 44-minute increase in category 3 (N = 40, P = 0.02). While FMD% increased in the entire study population (P = 0.008) over 12 weeks, no differences were observed between the categories (P = 0.73). In category 1, FMD% improvement was associated achievement of ≥20 minutes/day of moderate intensity PA in bouts ≥ 10 minutes in length. CONCLUSIONS Reductions of up to 100 minutes of sedentary time per day over 12 weeks was not significantly associated with improved vascular endothelial function in older adults. FMD% was significantly higher among those with lower sedentary behavior and concomitant moderate-intensity PA of ≥20 minutes/day in bouts.
Diabetologia, 2012
Aims/hypothesis We investigated whether objectively measured sedentary time and interruptions in sedentary time are associated with metabolic factors in people with type 2 diabetes. Methods We studied 528 adults (30-80 years) with newly diagnosed type 2 diabetes, who were participants in a diet and physical activity intervention. Waist circumference (WC), fasting HDL-cholesterol, insulin and glucose levels, HOMA of insulin resistance (HOMA-IR) and physical activity (accelerometer) were measured at baseline and at 6 months follow-up. Linear regression models were used to investigate cross-sectional and longitudinal associations of accelerometer-derived sedentary time and breaks in sedentary time (BST) with metabolic variables. Results In cross-sectional analyses each hour of sedentary time was associated with larger WC (unstandardised regression coefficient [B] [95% CI] 1.89 cm [0.94, 2.83]; p<0.001), higher insulin (B08.22 pmol/l [2.80, 13.65]; p00.003) and HOMA-IR (B00.42 [0.14, 0.70]; p00.004), and lower HDLcholesterol (B0−0.04 mmol/l [−0.06, −0.01]; p00.005). Adjustment for WC attenuated all associations. Each BST was associated with lower WC (B0−0.15 cm [− 0.24, −0.05]; p00.003) and there was evidence of a weak linear association with HDL-cholesterol, but no association with insulin levels or HOMA-IR. Volume of sedentary time at baseline predicted HDL-cholesterol (B0−0.05 mmol/l [−0.08, −0.01]; p00.007), insulin levels (B08.14 pmol/l [0.1.51, 14.78]; p00.016) and HOMA-IR (B00.49 [0.08, 0.90]; p00.020) at 6 months, though not WC. Baseline BST did not substantially predict any metabolic variables at follow-up. No change was seen in sedentary time or BST between baseline and 6 months follow-up. Conclusions/interpretation Higher sedentary time is associated with a poorer metabolic profile in people with type 2 diabetes.
Sports medicine (Auckland, N.Z.), 2018
The aim was to conduct a systematic review and meta-analysis analyzing the impact of up to 24 h of prolonged sitting on postprandial glucose, insulin and triglyceride responses, blood pressure and vascular function, in comparison to sitting interrupted with light- to moderate-intensity physical activity. To be included, studies had to examine the impact of prolonged sitting lasting < 24 h in apparently healthy males or females of any age. Studies were identified from searches of the MEDLINE, CINAHL and SportDISCUS databases on July 6, 2016. Study quality was assessed using the Downs and Black Checklist; publication bias was assessed via funnel plot. Forty-four studies met the inclusion criteria for the systematic review; of these, 20 were included in the meta-analysis, which compared prolonged sitting to the effects of interrupting sitting with regular activity breaks on postprandial glucose, insulin and triglycerides. When compared to prolonged sitting, regular activity breaks l...
Diabetologia, 2017
We aimed to examine the effects of breaking sitting with standing and light-intensity walking vs an energy-matched bout of structured exercise on 24 h glucose levels and insulin resistance in patients with type 2 diabetes. In a randomised crossover study, 19 patients with type 2 diabetes (13 men/6 women, 63 ± 9 years old) who were not using insulin each followed three regimens under free-living conditions, each lasting 4 days: (1) Sitting: 4415 steps/day with 14 h sitting/day; (2) Exercise: 4823 steps/day with 1.1 h/day of sitting replaced by moderate- to vigorous-intensity cycling (at an intensity of 5.9 metabolic equivalents [METs]); and (3) Sit Less: 17,502 steps/day with 4.7 h/day of sitting replaced by standing and light-intensity walking (an additional 2.5 h and 2.2 h, respectively, compared with the hours spent doing these activities in the Sitting regimen). Blocked randomisation was performed using a block size of six regimen orders using sealed, non-translucent envelopes. I...
Diabetes Care, 2008
OBJECTIVE—Total sedentary (absence of whole-body movement) time is associated with obesity, abnormal glucose metabolism, and the metabolic syndrome. In addition to the effects of total sedentary time, the manner in which it is accumulated may also be important. We examined the association of breaks in objectively measured sedentary time with biological markers of metabolic risk. RESEARCH DESIGN AND METHODS—Participants (n = 168, mean age 53.4 years) for this cross-sectional study were recruited from the 2004–2005 Australian Diabetes, Obesity and Lifestyle study. Sedentary time was measured by an accelerometer (counts/minute−1 < 100) worn during waking hours for seven consecutive days. Each interruption in sedentary time (counts/min ≥100) was considered a break. Fasting plasma glucose, 2-h plasma glucose, serum triglycerides, HDL cholesterol, weight, height, waist circumference, and resting blood pressure were measured. MatLab was used to derive the breaks variable; SPSS was used ...
Sedentary Behaviour - A Contemporary View, 2021
Sedentary behavior (SB) is one of the common leading modifiable risk factor for cardiovascular (CV) morbidity and all-cause mortality. However, not much is known concerning the relationship between SB and CV risk factors. This chapter aimed to explore the scientific knowledge that examines the association between SB and CV risk factors and its association with the development of CVD. Besides, the focus on preventing the SB by avoiding prolonged sitting and breaking-up the extended periods of sitting, and participating in physical activity (PA) are usually highlighted in this chapter, explaining how these intervention protocols can reduce the burden of CVD due to SB. Regardless of the known benefits of both PA and taking frequent breaks when engaging in sedentary tasks, the adaptation of a physically active lifestyle has remained very low because of various reasons; habitual behavior, insufficient or lack of time, misconceptions of CVD related health benefits from PA. Thus, it is ver...
BMC Public Health, 2011
Background: The rising prevalence of Type 2 Diabetes Mellitus (T2DM) is a major public health problem. There is an urgent need for effective lifestyle interventions to prevent the development of T2DM. Sedentary behaviour (sitting time) has recently been identified as a risk factor for diabetes, often independent of the time spent in moderate-to-vigorous physical activity. Project STAND (Sedentary Time ANd Diabetes) is a study which aims to reduce sedentary behaviour in younger adults at high risk of T2DM. Methods/Design: A reduction in sedentary time is targeted using theory driven group structured education. The STAND programme is subject to piloting and process evaluation in line with the MRC framework for complex interventions. Participants are encouraged to self-monitor and self-regulate their behaviour. The intervention is being assessed in a randomised controlled trial with 12 month follow up. Inclusion criteria are a) aged 18-40 years with a BMI in the obese range; b) 18-40 years with a BMI in the overweight range plus an additional risk factor for T2DM. Participants are randomised to the intervention (n = 89) or control (n = 89) arm. The primary outcome is a reduction in sedentary behaviour at 12 months as measured by an accelerometer (count < 100/min). Secondary outcomes include physical activity, sitting/lying time using the ActivPAL posture monitor, fasting and 2 h oral glucose tolerance test, lipids, inflammatory biomarkers, body weight, waist circumference, blood pressure, illness perceptions, and efficacy beliefs for behaviour change.