Sedentary behavior has a strong association with cardiovascular disease (CVD) risk, which may be independent of physical activity. To date, the mechanism(s) that mediate this relationship are poorly understood. We hypothesize that sedentary behavior modifies key hemodynamic, inflammatory, and metabolic processes resulting in impaired arterial health. Subsequently, these vascular impairments directly and indirectly contribute to the development of CVD.

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Background: Subjective measures of sedentary behaviour (SB) (i.e. questionnaires and diaries/logs) are widely implemented, and can be useful for capturing type and context of SBs. However, little is known about comparative validity and reliability. The aim of this systematic review and meta-analysis was to: 1) identify subjective methods to assess overall, domain-and behaviour-specific SB, and 2) examine the validity and reliability of these methods. Methods: The databases MEDLINE, EMBASE and SPORTDiscus were searched up to March 2020. Inclusion criteria were: 1) assessment of SB, 2) evaluation of subjective measurement tools, 3) being performed in healthy adults, 4) manuscript written in English, and 5) paper was peer-reviewed. Data of validity and/or reliability measurements was extracted from included studies and a meta-analysis using random effects was performed to assess the pooled correlation coefficients of the validity. Results: The systematic search resulted in 2423 hits. After excluding duplicates and screening on title and abstract, 82 studies were included with 75 self-reported measurement tools. There was wide variability in the measurement properties and quality of the studies. The criterion validity varied between poor-to-excellent (correlation coefficient [R] range − 0.01-0.90) with logs/diaries (R = 0.63 [95%CI 0.48-0.78]) showing higher criterion validity compared to questionnaires (R = 0.35 [95%CI 0.32-0.39]). Furthermore, correlation coefficients of single-and multiple-item questionnaires were comparable (1-item R = 0.34; 2-to-9-items R = 0.35; ≥10-items R = 0.37). The reliability of SB measures was moderate-to-good, with the quality of these studies being mostly fair-to-good. Conclusion: Logs and diaries are recommended to validly and reliably assess self-reported SB. However, due to time and resources constraints, 1-item questionnaires may be preferred to subjectively assess SB in large-scale observations when showing similar validity and reliability compared to longer questionnaires. Registration number: CRD42018105994.

Aims: The aim of this study was to examine physical activity and sedentary behaviour characteristics of ambulatory and community-dwelling patients with dementia compared to cognitively healthy age-, sex- and weight-matched controls. Methods: In this cross-sectional study, we included community-dwelling dementia patients (n = 45, age 79.6 ± 5.9 years, Mini-Mental State Examination [MMSE] 22.8 ± 3.2) and matched controls (n = 49, age 80.0 ± 7.7 years, MMSE 29.0 ± 1.2). Participants wore a wrist accelerometer for 7 days to assess sedentary time, sedentary bout duration and time spent in very light, light-to-moderate and moderate-to-vigorous physical activities. Results: Relative sedentary time and sedentary bout duration was significantly higher in dementia patients than in controls (median [interquartile range] 57% [49–68] vs. 55% [47–59] and 18.3 [16.4–21.1] min vs. 16.6 [15.3–18.4] min, p = 0.042 and p = 0.008, respectively). In addition, dementia patients spent a lower percentage of their waking time in light-to-moderate and moderate-to-vigorous intensity physical activities (20% [15–23] vs. 22% [18–25] and 5% [2–10] vs. 10% [5–13], p = 0.017 and p = 0.001, respectively). Conclusion: We revealed that dementia patients are more sedentary and perform less physical activity than cognitively healthy controls. This may have clinically important consequences, given the observation that sedentary behaviour and little physical activity independently predict all-cause mortality and morbidity.

Objectives. Carotid artery reactivity (CAR%), involving carotid artery diameter responses to a cold pressor test, is a non-invasive measure of conduit artery function in humans. This study examined: 1. the impact of age and cardiovascular risk factors on the CAR% and 2. The relationship between CAR% and coronary artery vasodilator responses to the cold pressor test. Methods. Ultrasound was used to measure resting and peak carotid artery diameters during the cold pressor test, with CAR% being calculated as the relative change from baseline (%). We compared CAR% between young (n=50, 24±3 years) and older participants (n=44, 61±8 years), and subsequently assessed relationships between CAR% and traditional cardiovascular risk factors in 50 participants (44±21 years). Subsequently, we compared left anterior descending (LAD) artery velocity (using transthoracic Doppler) with carotid artery diameter (i.e. CAR%) during the cold pressor test (CPT, n=33, 37±17 years). Results. A significantly larger CAR% was found in young versus older healthy participants (4.1±3.7 versus 1.8±2.6, P<0.001). Participants without cardiovascular risk factors demonstrated a higher CAR% compared to those with ≥2 risk factors (2.9±2.9 versus 0.5±2.9, P=0.019). Carotid artery diameter and LAD velocity increased during CPT (P<0.001). Carotid diameter and change in velocity correlated with LAD velocity (r=0.486 and 0.402, P<0.004 and 0.02, respectively). Conclusion. Older age and cardiovascular risk factors are related to lower CAR%, whilst CAR% shows good correlation with coronary artery responses to the CPT. Therefore, CAR% may represent a valuable technique to assess cardiovascular risk, whilst CAR% seems to reflect coronary artery vasodilator function.