Comparison of hip and wrist accelerometers in a pre-adolescent population in free-living and semi-structured physical activity

PURPOSE: The primary aim of this study was to examine the accuracy of a hip (Evenson algorithm) and wrist-worn (Crouter algorithm) accelerometer in assessing time spent in different intensity categories in pre-adolescent girls during semi-structured dance classes using direct observation (D.O.) as the criterion measure. The secondary aim of this study was to examine the validity of a wrist-worn accelerometer for dichotomizing pre-adolescent girls as meeting or not meeting different preselected doses of moderate-to-vigorous PA compared to the hip-worn accelerometer. METHODS: Data were collected and analyzed on a total of 6 participants (age = 10.22 ± 2.38) for the primary aim. Additionally, data was collected and analyzed on a total of 20 participants (age = 8.6 ± 1.6) for the secondary aim. RESULTS: Compared to D.O., the wrist-worn accelerometer was inaccurate in measuring time spent in light PA, vigorous PA and MVPA. Additionally, the hip-worn accelerometer was inaccurate in measuring time spent in sedentary time, light PA, vigorous PA and total PA. Further, for the secondary aim, there was a significant difference between device location and meeting PA dosage for three days and five days. CONCLUSION: Traditional accelerometer algorithms rely on the activity count cut-point method which provides mixed to poor results of activity intensity classification regardless of wear location. Future research should move away from the activity count cut-point method and aim to develop algorithms that use more of the rich data available from the accelerometers’ acceleration signal

Using Situation Awareness as a Measure of Driver Hazard Perception Ability

The present study investigated the effectiveness of a tablet-based hazard anticipation training program on teenage drivers. Verbal and eye tracking protocols were mapped to Endsley’s three level model of situation awareness (SA) as a means of measuring schema development. Participants were trained with a tablet based training program containing hazard identification scenarios. After six months they were asked to drive a simulator and on-road drive with various hazard scenarios. Results showed a significant difference between trained teen drivers and placebo teen drivers, both in eye tracking and verbal protocol. Verbal protocol and eye tracking protocol of trained teen drivers showed higher order of situation awareness in either of Endsley’s model levels. This means trained group were more capable of identifying and mitigating the hazards and verbalizing the future states of the environment. In conclusion, the tablet based hazard identification and anticipation training program could be an effective post-licensure training program to give better insight of “what is going on” in driving environment

Do associations of physical activity and sedentary behaviour with cardiovascular disease and mortality differ across socioeconomic groups? A prospective analysis of device-measured and self-reported UK Biobank data

OBJECTIVE: To examine if individual-level and area-level socioeconomic status (SES) modifies the association of moderate-to-vigorous physical activity (MVPA), domain-specific physical activity and sedentary behaviour with all-cause mortality (ACM) and incident cardiovascular disease (CVD). METHODS: We used self-reported (International Physical Activity Questionnaire short form) and accelerometer-measured physical activity and sedentary behaviour data from the UK Biobank. We created an individual-level composite SES index using latent class analysis of household income, education and employment status. The Townsend Index was the measure of area-level SES. Cox proportional hazards regression models stratified across SES were used. RESULTS: In 328 228 participants (mean age 55.9 (SD 8.1) years, 45% men) with an average follow-up of 12.1 (1.4) years, 18 033 deaths and 98 922 incident CVD events occurred. We found an increased ACM risk of low physical activity and high sedentary behaviour and an increased incident CVD risk of low accelerometer-measured moderate-to-vigorous physical activity (ACCEL_MVPA) and high sitting time. We observed statistically significant interactions for all exposures in ACM analyses by individual-level SES (p<0.05) but only for screen time in area-level SES–ACM analysis (p<0.001). Compared with high self-reported moderate-to-vigorous physical activity (IPAQ_MVPA), adjusted ACM HRs for low IPAQ_MVPA were 1.14 (95% CI 1.05 to .25), 1.15 (95% CI 1.06 to 1.24) and 1.22 (95% CI 1.13 to 1.31) in high, medium and low individual-level SES, respectively. There were higher detrimental associations of low ACCEL_MVPA with decreasing area-level SES for both outcomes and of high screen time with ACM in low area-level SES. CONCLUSION: We found modest evidence suggesting that the detrimental associations of low MVPA and high screen time with ACM and incident CVD are accentuated in low SES groups

Universal quantum computation using the discrete time quantum walk

A proof that continuous time quantum walks are universal for quantum computation, using unweighted graphs of low degree, has recently been presented by Childs [PRL 102 180501 (2009)]. We present a version based instead on the discrete time quantum walk. We show the discrete time quantum walk is able to implement the same universal gate set and thus both discrete and continuous time quantum walks are computational primitives. Additionally we give a set of components on which the discrete time quantum walk provides perfect state transfer.Comment: 9 pages, 10 figures. Updated after referee comments - Section V expanded and minor changes to other parts of the tex

Impaired aortic distensibility measured by computed tomography is associated with the severity of coronary artery disease.

Impaired aortic distensibility index (ADI) is associated with cardiovascular risk factors. This study evaluates the relation of ADI measured by computed tomographic angiography (CTA) with the severity of coronary atherosclerosis in subjects with suspected coronary artery disease (CAD). Two hundred and twenty-nine subjects,age 63 ± 9 years, 42% female, underwent coronary artery calcium (CAC) scanning and CTA, and their ADI and Framingham risk score (FRS) were measured. End-systolic and end-diastolic (ED) cross-sectional-area(CSA) of ascending-aorta (AAo) was measured 15-mm above the left-main coronary ostium. ADI was defined as: [(Δlumen-CSA)/(lumen-CSA in ED × systemic-pulse-pressure) × 10(3)]. ADI measured by 2D-trans-thoracic echocardiography (TTE) was compared with CTA-measured ADI in 26 subjects without CAC. CAC was defined as 0, 1-100, 101-400 and 400+. CAD was defined as luminal stenosis 0, 1-49% and 50%+. There was an excellent correlation between CTA- and TTE-measured ADI (r(2)=0.94, P=0.0001). ADI decreased from CAC 0 to CAC 400+; similarly from FRS 1-9% to FRS 20% + (P&lt;0.05). After adjustment for risk factors, the relative risk for each standard deviation decrease in ADI was 1.66 for CAC 1-100, 2.26 for CAC 101-400 and 2.32 for CAC 400+ as compared to CAC 0; similarly, 2.36 for non-obstructive CAD and 2.67 for obstructive CAD as compared to normal coronaries. The area under the ROC-curve to predict significant CAD was 0.68 for FRS, 0.75 for ADI, 0.81 for CAC and 0.86 for the combination (P&lt;0.05). Impaired aortic distensibility strongly correlates with the severity of coronary atherosclerosis. Addition of ADI to CAC and traditional risk factors provides incremental value to predict at-risk individuals

Fractal complexity of daily physical activity and cognitive function in a midlife cohort

High stability of fluctuation in physiological patterns across fixed time periods suggest healthy fractal complexity, while greater randomness in fluctuation patterns may indicate underlying disease processes. The importance of fractal stability in mid-life remains unexplored. We quantified fractal regulation patterns in 24-h accelerometer data and examined associations with cognitive function in midlife. Data from 5097 individuals (aged 46) from the 1970 British Cohort Study were analyzed. Participants wore thigh-mounted accelerometers for seven days and completed cognitive tests (verbal fluency, memory, processing speed; derived composite z-score). Detrended fluctuation analysis (DFA) was used to examine temporal correlations of acceleration magnitude across 25 time scales (range: 1 min-10 h). Linear regression examined associations between DFA scaling exponents (DFAe) and each standardised cognitive outcome. DFAe was normally distributed (mean ± SD: 0.90 ± 0.06; range: 0.72-1.25). In males, a 0.10 increase in DFAe was associated with a 0.30 (95% Confidence Interval: 0.14, 0.47) increase in composite cognitive z-score in unadjusted models; associations were strongest for verbal fluency (0.10 [0.04, 0.16]). Associations remained in fully-adjusted models for verbal fluency only (0.06 [0.00, 0.12]). There was no association between DFA and cognition in females. Greater fractal stability in men was associated with better cognitive function. This could indicate mechanisms through which fractal complexity may scale up to and contribute to cognitive clinical endpoints

Association between device-measured stepping behaviours and cardiometabolic health markers in middle-aged women: The Australian Longitudinal Study on Women's Health

The associations between different types and contexts of stepping behaviors and cardiometabolic (CM) health markers are unclear. This study aimed to examine the associations of daily total, walking, stair, incidental and purposeful steps with cardiometabolic risk. A total of 943 women (mean age ± SD = 44.1 ± 1.6 years) from the Australian Longitudinal Study on Women's Health (ALSWH) were included in this cross-sectional study. Daily total, walking, stair, incidental, and purposeful steps were measured using thigh-worn accelerometry. Outcomes comprised of CM markers of adiposity, blood pressure, resting heart rate, lipids, glycaemia, and the composite CM score. We used generalized linear modeling and multiple linear regression to assess the associations. We observed that all stepping behaviors were beneficial to CM health, for example, compared to the lowest quartile (Q1), the change of the composite CM score across low to high quartile of purposeful steps was −0.12 (Q2, 95% CI: −0.41, 0.17), −0.16 (Q3, −0.46, 0.14), and −0.36 (Q4, −0.66, −0.05). Stair steps showed linear associations with blood pressure and adiposity biomarkers, for example, the change of quartile of waist circumference was −1.45 cm (Q2, −4.35, 1.44), −3.56 cm (Q3, −6.52, −0.60), and −7.08 cm (Q4, −10.31, −3.86). Peak 30-min walking intensity showed independent association with adiposity biomarkers (p linear < 0.001 and p = 0.002 for waist circumference and BMI, respectively). Our study showed that all stepping forms were beneficial to CM health. Higher stair steps and peak 30-min walking cadence were associated with a steep decline of adiposity biomarkers. Purposeful steps showed more consistent associations with CM biomarkers than incidental steps

Brief bouts of device-measured intermittent lifestyle physical activity and its association with major adverse cardiovascular events and mortality in people who do not exercise: a prospective cohort study

BACKGROUND: Guidelines emphasise the health benefits of bouts of physical activity of any duration. However, the associations of intermittent lifestyle physical activity accumulated through non-exercise with mortality and major adverse cardiovascular events (MACE) remain unclear. We aimed to examine the associations of bouts of moderate-to-vigorous intermittent lifestyle physical activity (MV-ILPA) and the proportion of vigorous activity contributing within these bouts with mortality and MACE. METHODS: In this prospective cohort study, we used data from the UK Biobank on adults who do not exercise (ie, those who did not report leisure-time exercise) who had wrist-worn accelerometry data available. Participants were followed up until Nov 30, 2022, with the outcome of interest of all-cause mortality obtained through linkage with NHS Digital of England and Wales, and the NHS Central Register and National Records of Scotland, and MACE obtained from inpatient hospitalisation data provided by the Hospital Episode Statistics for England, the Patient Episode Database for Wales, and the Scottish Morbidity Record for Scotland. MV-ILPA bouts were derived using a two-level Random Forest classifier and grouped as short (<1 min), medium (1 to <3 min; 3 to <5 min), and long (5 to <10 min). We further examined the dose-response relationship of the proportion of vigorous physical activity contributing to the MV-ILPA bout. FINDINGS: Between June 1, 2013, and Dec 23, 2015, 103 684 Biobank participants wore an accelerometer on their wrist. 25 241 adults (mean age 61·8 years [SD 7·6]), of whom 14 178 (56·2%) were women, were included in our analysis of all-cause mortality. During a mean follow-up duration of 7·9 years (SD 0·9), 824 MACE and 1111 deaths occurred. Compared with bouts of less than 1 min, mortality risk was lower for bouts of 1 min to less than 3 min (hazard ratio [HR] 0·66 [0·53-0·81]), 3 min to less than 5 min (HR 0·56 [0·46-0·69]), and 5 to less than 10 min (HR 0·48 [0·39-0·59]). Similarly, compared with bouts of less than 1 min, risk of MACE was lower for bouts of 1 min to less than 3 min (HR 0·71 [0·54-0·93]), 3 min to less than 5 min (0·62 [0·48-0·81]), and 5 min to less than 10 min (0·59 [0·46-0·76]). Short bouts (<1 min) were associated with lower MACE risk only when bouts were comprised of at least 15% vigorous activity. INTERPRETATION: Intermittent non-exercise physical activity was associated with lower mortality and MACE. Our results support the promotion of short intermittent bouts of non-exercise physical activity of moderate-to-vigorous intensity to improve longevity and cardiovascular health among adults who do not habitually exercise in their leisure time. FUNDING: Australian National Health, Medical Research Council, and Wellcome Trust

Association between device-measured stepping behaviors and cardiometabolic health markers in middle-aged women: the Australian longitudinal study on women's health

The associations between different types and contexts of stepping behaviors and cardiometabolic (CM) health markers are unclear. This study aimed to examine the associations of daily total, walking, stair, incidental and purposeful steps with cardiometabolic risk. A total of 943 women (mean age ± SD = 44.1 ± 1.6 years) from the Australian Longitudinal Study on Women's Health (ALSWH) were included in this cross‐sectional study. Daily total, walking, stair, incidental, and purposeful steps were measured using thigh‐worn accelerometry. Outcomes comprised of CM markers of adiposity, blood pressure, resting heart rate, lipids, glycaemia, and the composite CM score. We used generalized linear modeling and multiple linear regression to assess the associations. We observed that all stepping behaviors were beneficial to CM health, for example, compared to the lowest quartile (Q1), the change of the composite CM score across low to high quartile of purposeful steps was −0.12 (Q2, 95% CI: −0.41, 0.17), −0.16 (Q3, −0.46, 0.14), and −0.36 (Q4, −0.66, −0.05). Stair steps showed linear associations with blood pressure and adiposity biomarkers, for example, the change of quartile of waist circumference was −1.45 cm (Q2, −4.35, 1.44), −3.56 cm (Q3, −6.52, −0.60), and −7.08 cm (Q4, −10.31, −3.86). Peak 30‐min walking intensity showed independent association with adiposity biomarkers (p linear &lt; 0.001 and p = 0.002 for waist circumference and BMI, respectively). Our study showed that all stepping forms were beneficial to CM health. Higher stair steps and peak 30‐min walking cadence were associated with a steep decline of adiposity biomarkers. Purposeful steps showed more consistent associations with CM biomarkers than incidental steps