Timing of physical activity in relation to liver fat content and insulin resistance

To develop healthy ageing interventions, longitudinal associations between objectively assessed physical behaviours and physical function need to be better understood. We assessed associations between accelerometer-assessed total physical activity (PA), moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), sedentary time and prolonged sedentary bout time, and clinically assessed physical function (grip strength, usual walking speed (UWS), chair stand speed) at two time-points in 3188 participants (≥ 60 years) of the EPIC-Norfolk study. Bidirectional associations were assessed using multivariable linear regression. Over an average of 6.1 years, baseline physical behaviours (greater total PA, MVPA and LPA, and less sedentary time) were associated with better subsequent walking and chair stand speed. Better baseline physical function was associated with better follow-up physical behaviours. There were no bidirectional associations between changes in physical behaviours and grip strength. Improvements in UWS were associated with improvements in all physical behaviours. Improvements in chair stand speed were associated with improvements in total PA, MVPA, and sedentary bout time. Improvements in physical behaviours were associated with improvements in UWS (3.1 cm/s/yr per 100 cpm/yr total PA, 3.6 cm/s/yr per hr/day/yr MVPA, 2.5 cm/s/yr per hr/day/yr LPA, − 2.9 cm/s/yr per hour/day/yr sedentary time, and − 1.6 cm/s/yr per hr/day/yr prolonged sedentary bout time). Only improvements in total PA, MVPA and sedentary bout time were associated with improvements in chair stand speed. In conclusion, we found bidirectional associations between changes in some physical behaviours and physical function and between baseline physical behaviours and subsequent physical function, highlighting the importance of considering the full range of physical behaviours to promote healthy ageing.

Metabolic syndrome (MetS) is highly prevalent in children and adolescents with obesity and places them at an increased risk of cardiovascular-related diseases. However, the associations between objectively measured movement-related behaviors and MetS diagnosis remain unexplored in youths with obesity. The aim was to compare profiles of sedentary (SED) time (more sedentary, SED+ vs. less sedentary, SED−), moderate to vigorous physical activity (MVPA) time (more active, MVPA+ vs. less active, MVPA−) and combinations of behaviors (SED−/MVPA+, SED−/MVPA−, SED+/MVPA+, SED+/MVPA−) regarding the MetS diagnosis. One hundred and thirty-four adolescents with obesity (13.4 ± 2.2 years) underwent 24 h/7 day accelerometry, waist circumference (WC), blood pressure (BP), high-density lipoprotein-cholesterol (HDL-c), triglycerides (TG) and insulin-resistance (IR) assessments. Cumulative cardiometabolic risk was assessed by using (i) MetS status (usual dichotomic definition) and (ii) cardiometabolic risk z-score (MetScore, mean of standardized WC, BP, IR, TG and inverted HDL-c). SED− vs. SED+ and MVPA+ vs. MVPA− had lower MetS (p < 0.01 and p < 0.001) and MetScore (p < 0.001). SED−/MVPA+ had the lowest risk. While SED and MVPA times were lower in SED−/MVPA− vs. SED+/MVPA+ (p < 0.001), MetScore was lower in SED−/MVPA− independently of body mass index (BMI) (p < 0.05). MVPA, but not SED, time was independently associated with MetS diagnosis (p < 0.05). Both MVPA (p < 0.01) and SED times (p < 0.05) were associated with MetScore independently of each other. A higher MVPA and lower SED time are associated with lower cumulative cardiometabolic risk.

To establish whether associations between sedentary behavior and cardiometabolic health differ when assessed by thigh-worn and waist-worn accelerometry. Participants were recruited from several areas in the United Kingdom. Sedentary behavior was assessed using the activPAL worn on the thigh and ActiGraph worn on the waist. Average total (TST), prolonged (bouts ≥30 min; PST) and breaks (BST) in sedentary time were calculated. Cardiometabolic health markers included: adiposity (body fat) and surrogate markers of adiposity ((waist circumference, body mass index [BMI]), lipids (total, low density lipoprotein, and high-density lipoprotein [HDL] cholesterol, triglycerides), blood pressure, and glucose (fasting, 2 h and glycated hemoglobin A1c). A clustered cardiometabolic risk score was calculated. Linear regression analysis examined the associations with cardiometabolic health. There were 1457 participants (mean age [± standard deviation], 59.38 ± 11.85 yr; 51.7% male; mean BMI, 30.19 ± 5.59 kg·m) included in the analyses. ActivPAL and ActiGraph sedentary variables were moderately correlated (0.416-0.511, P < 0.01); however, all variables were significantly different from each other (P < 0.05). Consistency was observed across devices in the direction and magnitude of associations of TST and PST with adiposity, surrogate markers of adiposity, HDL, triglycerides, and cardiometabolic risk score and for BST with adiposity, surrogate markers of adiposity, and cardiometabolic risk. Differences across devices were observed in associations of TST and PST with diastolic blood pressure, for TST with 2-h glucose and for BST with HDL. No other associations were observed for any other health marker for either device. Results suggest that associations with cardiometabolic health are largely comparable across the two common assessments of sedentary behavior but some small differences may exist for certain health markers.

BackgroundIdentifying leisure time activities performed before and after school that influence time in physical activity (PA) and/or time spent sedentary can provide useful information when designing interventions aimed to promote an active lifestyle in young people. The purpose of this study was to examine associations between mode of transportation to school, outdoor play after school, participation in exercise in clubs, and TV viewing with objectively assessed PA and sedentary behaviour in children.MethodsA total of 1327 nine- and 15-year-old children from three European countries (Norway, Estonia, Portugal) participated as part of the European Youth Heart Study. PA was measured during two weekdays and two weekend days using the MTI accelerometer, and average percent of time in moderate-to-vigorous PA (MVPA) and time spent sedentary were derived. Potential correlates were assessed by self-report. Independent associations between self-reported correlates with percent time in MVPA and percent time sedentary were analysed by general linear models, adjusted by age, gender, country, measurement period, monitored days and parental socio-economic status.ResultsIn 9-year-olds, playing outdoors after school was associated with higher percent time in MVPA (P < 0.01), while participation in sport clubs was associated with higher percent time in MVPA (P < 0.01) in 15-year-olds. No associations with percent time sedentary were observed in either age group.ConclusionFrequency of outdoor play after school is a significant correlate for daily time in MVPA in 9-year-olds, while this correlate is attenuated in favour of participation in sport and exercise in clubs in 15-year-olds. Targeting walking to school or reduced TV viewing time in order to increase time in daily MVPA in children is unlikely to be sufficient. Correlates related to time spent sedentary need further examination.

It is important to investigate how the different factors of physical activity and screen time influence each population group in order to design effective proposals for health promotion. This study aims to: (1) create an explanatory model to establish the relationships between moderate-vigorous physical activity time, screen time, family support, and peer support of adolescents in the region of Soria (Spain); (2) contrast the explanatory structural model according to the intensity of physical activity. A representative sample of 694 adolescents, aged 12-17 years, from the region of Soria was selected. The Four by One-Day Physical Activity Questionnaire, the Parent Support Scale, and the Peer Support Scale were administered. The data were treated according to a structural equation model to demonstrate the relationships between the study variables. The Chi-square p-values and standardised fit indices (CFI, NFI, IFI, TLI, and RMSEA) were appropriate. Moreover, acceptable parameters were obtained in the general equations. The theoretical model is useful to explain the relationships between moderate-vigorous physical activity, family support, peer support, and screen time. In addition, models that differentiate between moderate and vigorous physical activity independently are also useful. Peer support plays a particular role relative to physical activity time, and family support plays a specific role regarding screen time.

Breaking-up sedentary time is associated with impairment in activities of daily living

Breaking-up sedentary time is associated with impairment in activities of daily living

This study aimed to explore the associations between moderate to vigorous physical activity (MVPA) and sedentary time with renal function indices in adolescents with kidney disease. A cross-sectional study was conducted on 719 adolescents (median age 15y, 40.6% female) with kidney disease from the National Health and Nutrition Examination Survey 2007-2016. The exposures were MVPA time and sedentary time. Renal metabolic parameters included serum uric acid (SUA), creatinine, blood urea nitrogen, the estimated glomerular filtration rate (eGFR), and the albumin creatinine ratio. Weighted multivariate regression analysis was used to estimate associations between exposures and outcomes. After stratifying MVPA time, the regression effect values β (95% CI) for MVPA on SUA (Q2: -0.22 [-0.41 to -0.03]; Q3: -0.32 [-0.53 to -0.11]) and creatinine (Q2: -0.08 [-0.15 to -0.01]; Q3: -0.04 [-0.11 to 0.03]) gradually decreased with increasing MVPA time. In males (-0.76 [-1.19 to -0.32]), MVPA time was significantly associated with lower SUA levels compared with females (-0.14 [-0.38 to 0.10]). Notably, female adolescents who had an MVPA time exceeding 420minutes exhibited lower albumin creatinine ratio (-75.37 [-146.63 to -4.11]). In addition, both recreational MVPA time (-0.26 [-0.45 to -0.06]) and sedentary time (-3.15 [-5.83 to -0.46]) were negatively associated with eGFR. Our study found an association between MVPA and lower levels of SUA in male adolescents with kidney disease and albuminuria in female adolescents with kidney disease. In addition, MVPA was also negatively associated with creatinine and eGFR, whereas sedentary time was only associated with eGFR. Further studies are needed to confirm these findings.

ObjectiveWe sought to evaluate the performance of Fitbit in estimating ActiGraph‐derived moderate‐to‐vigorous physical activity (MVPA) and sedentary time in the knee osteoarthritis (OA) population.MethodsWe used data from two weeks of Fitbit and ActiGraph wear among knee OA subjects. In primary analyses, we used literature‐based ActiGraph thresholds of 200 and 1924 counts/min (triaxial vector magnitude) for sedentary and MVPA time as the gold standard to which we compared three sets of Fitbit thresholds informed by literature and data (Youden index). We also considered personalized, stride length–based Fitbit thresholds. In sensitivity analyses, we used uniaxial, vertical axis–based as well as personalized, BMI‐based ActiGraph thresholds. We calculated agreement, sensitivity, and specificity of Fitbit in classifying sedentary and MVPA time.ResultsIn the primary analysis (vector magnitude thresholds), maximum agreement for sedentary and MVPA time was 67.0% from the Youden index–based and 91.1% from the stride length–based Fitbit thresholds. For sedentary time, the 20 strides/min threshold had the highest sensitivity (97.6%), and Youden‐derived 1 stride/min had the highest specificity (51.6%). For MVPA, Youden‐derived 14 strides/min yielded 72.8% sensitivity, and using stride length yielded 98.6% specificity. MVPA time ranged from 49‐323 min/d, depending on threshold used, with literature‐based and personalized thresholds leading to more conservative estimates of MVPA than Youden‐derived thresholds.ConclusionUsing Fitbit for MVPA and sedentary time assessment may lead to inaccurate estimates of both. Fitbit MVPA estimates were generally more conservative than ActiGraph estimates. Incorporating individuals’ characteristics did not meaningfully improve Fitbit performance. Caution should be exercised when measuring activity using Fitbit.

Exercise is an important strategy to improve metabolic outcomes and to reduce risk of developing type 2 diabetes. Previous studies have shown that frequent interruptions of extended sitting with standing or light physical activity reduced triacylglycerol levels – elevated triacylglycerol levels is linked to higher concentrations of fat in the liver, which in turn is strongly associated with insulin resistance. Previous studies have demonstrated that exercise is linked to reduced liver fat and improved insulin sensitivity but the timing of physical activity throughout the day may be a factor in metabolic health. Pre-clinical studies have shown daytime-dependent changes in exercise capacity and metabolic risk markers but few such investigations have been performed in humans. In a study published in Diabetologia, data from the Netherlands Epidemiology of Obesity (NEO) study, a population-based prospective cohort study was used to investigate processes involved in the development of obesity-related diseases. Study participants had a self-reported body mass index (BMI) of >27 kg/m2, aged between 45 and 65 years resulting in a study population of 6,671 individuals. Participants underwent a physical examination during which blood samples were taken to measure fasting and postprandial blood glucose and insulin levels, while demographic, lifestyle and clinical information were obtained via questionnaire. 35% of participants underwent MRI study to have their liver fat content measured. A further random subsample of 955 participants were given a combined accelerometer and heart rate monitor to wear for four consecutive days and nights to monitor movement and activity. Analysis of results obtained from 775 participants for whom complete data sets were available. After adjusting for variables such as age, sex, ethnicity and total body fat, the researchers observed that higher total Physical activity Energy Expenditure (PAEE) were associated with both reduced liver fat content and reduced insulin resistance. An association was also found between insulin resistance and the timing of moderate to vigorous physical activity (MVPA) during the day: performing MVPA in the afternoon or evening was linked to reduced insulin resistance, by 18% and 25% respectively, compared to an even distribution of activity throughout the day, even after adjustment for total amount of MVPA. There was no significant difference in insulin resistance between morning activity and activity spread evenly over the day. These results suggest that timing of physical activity throughout the day is relevant for the beneficial effects of physical activity on insulin sensitivity and should be incorporated into physical activity recommendation. Further studies should assess whether optimal timing of physical activity reduced the occurrence of type 2 diabetes and underlying mechanism for this.

To examine the associations of moderate-to-vigorous physical activity (MVPA) and time spent sedentarily with cardiometabolic risk factors in children and adolescents. The data from 14 studies were pooled. This summary is of the associations between baseline activity levels and cardiometabolic risk factors measured in the cohort that was followed for a mean 2.1 years. The data were drawn from studies (1998-2009) in Australia, Brazil, Europe, and the United States by the International Children's Accelerometry Database (ICAD) Collaborators. At baseline, the 20,871 participants in 14 studies were 4 to 18 years of age. Baseline and follow-up data on waist circumference were available for 6413 participants from 7 studies. The children's time spent in activity and time spent sedentarily were objectively measured through the use of accelerometers (actigraphs) from which physical activity counts per minute (cpm) could be obtained in a standard way. Sedentary time was defined as all minutes showing <100 cpm, whereas MVPA time was minutes with >3000 cpm. Anthropometric and cardiometabolic measures were initially recorded at baseline. The main end points were the cardiometabolic outcomes of abdominal adiposity (waist circumference), glucose metabolism and lipid metabolism (fasting insulin, triglycerides, and HDL cholesterol), and resting systolic blood pressure (SBP). In each study the relations between cpm, MVPA, and sedentary time were adjusted for each other. Regression coefficients were calculated to allow cross-sectional random effects meta-analysis adjusted for sex, age, and monitor-wear time, and further adjusted in the prospective study by baseline values and follow-up time. At a median of 2.1 years of follow-up (range, 0.3-8.0 years), time spent in MVPA at baseline was not associated with waist circumference (β = 0.00024; 95% confidence interval [CI] -0.0057 to 0.0062). Similarly, baseline sedentary time was not associated with follow-up waist circumference (β = -0.0024; 95% CI, -0.0057 to 0.0010). A greater waist circumference at baseline was not associated with time spent in MVPA at follow-up (β = -0.0037; 95% CI, -0.60 to 0.052), but was associated with more sedentary time at follow-up (β = 0.40; 95% CI, 0.19-0.61). At baseline, total physical activity cpm and MVPA were negatively associated with baseline waist circumference, SBP, and serum levels of fasting insulin and triglycerides. Baseline time per day in sedentary activity was positively associated with fasting insulin level but not with any other cardiometabolic risk factor. Although children's level of physical activity and time spent sedentarily were cross-sectionally related to some baseline cardiometabolic risk factors, they did not predict waist circumference measured at follow-up. However, waist circumference at baseline did predict more sedentary time at follow-up.

The aims of this study were to describe the volume and patterns of objectively assessed sedentary behaviour, light intensity physical activity (LPA) and moderate-vigorous physical activity (MVPA), and to examine socio-demographic correlates, among adults living with type 2 diabetes. Participants (n = 166) wore an accelerometer (Actigraph® GT3X+) for seven consecutive days during waking hours and completed a questionnaire. Physical activity (PA) and sedentary time were described, and multivariable linear regression was used to estimate associations between socio-demographic characteristics and sedentary time and PA. Participants, 46% of whom were female, had a mean age of 65.4 years (standard deviation (SD) = 9.5), body mass index (BMI) of 31.5 (6.6) kg/m2 and had been living with diabetes for an average of 13.1 (7.6) years. Participants were sedentary for 543.6 minutes/day, spent 273.4 minutes/day and 22.4 minutes/day in LPA and MVPA respectively. BMI was associated with increased sedentary time and reduced LPA (-2.5 minutes/day, 95% CI: -4.33 to -0.70) and MVPA (-0.62 minutes/day, 95% CI: -1.05 to -0.18) time. Compared with males, females had more LPA (34.4 minutes/day, 95% CI: 10.21-58.49) and less MVPA (-6.2 minutes/day, 95% CI: -12.04 to -0.41) time. Unemployed participants had 30.05 minutes more MVPA (95% CI: 3.35-56.75) than those who were employed or homemakers, and those not reporting income had 13 minutes/day more MVPA time than participants in the lowest income category (95% CI: 3.46-22.40). Adults living with type 2 diabetes were not sufficiently active and were highly sedentary. Our results emphasize the need for more research exploring the diabetes-related health outcomes of sedentary behaviour and physical inactivity among people living with type 2 diabetes.

Although correlates of physical activity (PA) have been extensively examined in both children and adolescents who are typically developing, little is known about correlates of moderate to vigorous physical activity (MVPA) and sedentary time in adolescents with intellectual and developmental disabilities (IDD). Therefore, we examined intrapersonal, interpersonal and environmental factors and their association with device-based MVPA and sedentary time in adolescents with IDD. MVPA and sedentary time was assessed using a hip-worn ActiGraph model wGT3x-BT tri-axial accelerometer across a 7-day period in adolescents with IDD and one of their parents. Pearson and point-biserial correlations were calculated to inspect the associations of PA (MVPA, sedentary time) with intrapersonal factors (demographic characteristic, BMI, waist circumference, motor ability, muscle strength, grip strength, cardiovascular fitness and self-efficacy for PA), interpersonal factors (parent demographics, parent BMI, parent MVPA and sedentary time, family social support for PA, parent barriers and support for PA, parent's beliefs/attitudes towards PA and number of siblings), and environmental factors (meteorologic season and COVID-19). Ordinary least squares regression was used to estimate the unique contributions of key factors to PA after controlling for participants' age, sex, race, waist circumference and total wear time. Ninety-two adolescents (15.5±3.0years old, 21.7% non-White, 6.5% Hispanic, 56.5% female) provided valid accelerometer data. Average sedentary time was 494.6±136.4min/day and average MVPA was 19.8±24.2min/day. Age (r=0.27, P=0.01), diagnosis of congenital heart disease (r=-0.26, P=0.01) and parent sedentary time (r=0.30, P=0.01) were correlated with sedentary time. BMI (r=-0.24, P=0.03), waist circumference (r=-0.28, P=0.01), identifying as White (r=-0.23, P=0.03) and parent MVPA (r=0.56, P<0.001) were correlated with MVPA. After adjusting for the adolescent's age, sex, race, waist circumference, and total wear time, the association between parent and adolescent MVPA remained significant (b=0.55, P<0.01, partial η2 =0.11). The results of this study provide evidence that race, waist circumference and parental MVPA may influence the amount of MVPA in adolescents with IDD. The limited available information and the potential health benefits of increased MVPA highlight the need to evaluate the effectiveness of multi-component interventions targeting both intrapersonal and interpersonal levels to promote increased PA in adolescents with IDD.

Purpose The purpose of this study is to measure the daily physical activity of male and female middle school students according to the period (VD: vaction day, SNPE: school day no PE, SPE: school day with PE) by using 3-axis accelerometer, and to compare the characteristics of adolescent physical activity according to gender and period. Methods The subjects were 130 middle school students (68 male, 62 female students). Data collection was performed using a 3-axis accelerometer(GT3X model, ActiGraph). Collected data were converted into time by intensity and rate using physical activity analysis program (Actilife v6.11.9) and analyzed by statistical program (SPSS 25.0). One-way ANOVA and independent sample t-test were used for statistical analysis. Tukey's HSD was used as a post analysis. The statistical significance level was .05. Results As a result, during each periods(VD, SNPE, and SPE), except for MVPA(moderate to vigorous physical activity) time on SPE, sedentary and MVPA time were significantly higher in female students, and low intensity and total physical activity time were significantly higher in male students. For male students, total physical activity time was higher in the order of SPE, SNPE, and VD, and for female students, physical activity time during the semester(SNPE and SPE) was significantly higher than VD. For male students, MVPA time was significantly high in order of SPE, SNPE, and VD, and for female students, it was high in order of SPE, SNPE, and VD but only significant difference occurred between SPE and VD. For both male and female students, sedentary time was high in the order of VD, SNPE, and SPE, but the sedentary time during vacation was significantly higher than during the semester. Conclusions When summarizing the results, first, it was confirmed that school and physical education classes as a physical activity space play a significant role in physical activity, especially MVPA, of male and female middle school students, second, the physical activity effect of physical education class was found to be more effective in male students. Based on the results of this study, it is necessary to conduct studies on various grades and to explore various factors affecting physical activity in a complex way.

BackgroundPhysical activity has emerged as an important lifestyle factor for primary prevention of numerous diseases, including postmenopausal breast cancer. No study to date has assessed the acute and long-term effects of year-long aerobic exercise programs differing in prescribed exercise volume on physical activity and sedentary time in postmenopausal women. Therefore, we aimed to examine the effects of two moderate-vigorous intensity exercise doses on total, light and moderate-vigorous intensity physical activity times, and sedentary time in postmenopausal women during the year-long intervention and one year later.MethodsThe Breast Cancer and Exercise Trial in Alberta (BETA) was a two-center, two-arm, 12-month randomized controlled trial that included 400 previously inactive postmenopausal women randomized to either 150 (MODERATE) or 300 (HIGH) minutes/week of aerobic exercise. Physical activity and sedentary time were assessed at baseline, 6- (intervention mid-point), 12- (prior to end of intervention) and 24-months (follow-up) with waist-mounted accelerometers (Actigraph GTX3®). Self-reported activity and sedentary time at baseline, 12- and 24-months was also assessed (Past Year Total Physical Activity Questionnaire and SIT-Q). Intention-to-treat analyses were conducted using linear mixed models and adjusted for baseline variables.ResultsBoth physical activity interventions led to increases in objective and subjective measures of total and moderate-vigorous intensity/recreational physical activity time, coupled with decreases in sedentary time, at 6- and 12-months compared to baseline. Additionally, greater increases in accelerometry-derived total physical activity time at 6- and 12-months, and self-reported recreational activity time at 12-months, compared to baseline were noted in the HIGH versus MODERATE groups. Decreases in total, light and moderate-vigorous intensity physical activity time, and an increase in sedentary time, in both groups were noted at 24-months compared to 12-months. A decrease in light intensity physical activity time in both groups at 24-months compared to baseline was also noted.ConclusionThese findings have important health implications, suggesting that total physical activity time can be increased with greater volumes of prescribed exercise, but that additional support and resources could be used to promote the maintenance of these high levels of aerobic exercise participation following study completion.Trial registrationclinicaltrials.gov identifier: NCT01435005 (BETA Trial). Registred September 15th 2011 (retrospectively registered).