Background: Sedentary behaviour in general and sitting time in particular is an emerging global health concern. The aim of this study was to provide data on the prevalence of sitting time in German adults and to examine socio-demographic and environmental correlates of sitting time. Methods. A representative sample of German adults (n = 2000; 967 men, 1033 women; 49.3 ±17.6 years of age) filled in the Global Physical Activity Questionnaire, including one question on overall sitting time and answered questions about the neighbourhood environment, as well as concerning demographics. Daily sitting time was stratified by gender, age group, BMI, educational and income level, as well as physical activity (PA). To identify socio-demographic and environmental correlates of sitting time, we used a series of linear regressions. Results: The overall median was 5 hours (299 minutes) of sitting time/day and men sat longer than women (5 vs. 4 hours/day; p &lt; 0.05). In both genders age and PA were negatively and the educational level positively associated with sitting time. The level of income was not a correlate of sitting time in multivariate analyses. Sitting time was significantly positively associated with higher neighbourhood safety for women. The variance of the multivariate model ranged from 16.5% for men to 8.9% for women. Conclusions: The overall sitting time was unequally distributed in the German adult population. Our findings suggest implementing specific interventions to reduce sitting time for subgroups such as men, younger aged adults and adults with a higher education and lower PA. Future studies should enhance our understanding of the specific correlates of different types and domains of sitting in order to guide the development of effective public health strategies. / <p>:doi 10.1186/1471-2458-13-196</p>

Recent research suggests that sedentary behaviours have detrimental effects on the health and well-being of children, including effects on obesity. Specifically, television viewing is consistently associated with childhood obesity. Two explanations have been proposed: 1) reduced energy expenditure, and 2) increased food intake. However, it has been suggested that the association between television viewing and childhood obesity may be better explained by an increase in energy intake than by a reduction in energy expenditure. To date, children of different weight status have not been compared in their dietary patterns in front of the television, and it is not known if total sedentary time is linked with food intake in children. The objectives of this thesis are: 1) to determine if obese children consume food more frequently while watching television than normal weight children, and 2) to examine which of television viewing or total sedentary time better predicts dietary patterns in children. Overall, our results re-affirm the notion that television viewing is associated with obesity, although physical activity plays a role in this association. Also, children who are obese consume fast food and fruits/vegetables more frequently during television watching than normal weight children. Furthermore, television viewing appears to be a better predictor of dietary patterns in children than overall sedentary time. Globally, these results provide evidence for the deleterious effects of television viewing on children’s dietary patterns and justification for future intervention studies designed to reduce television viewing in children with obesity.

BACKGROUND. Unhealthy lifestyle behaviours such as physical inactivity are global risk factors for chronic disease. Despite this, a substantial proportion of the UK population fail to achieve the recommended levels of physical activity. This may partly be because the health messages presently disseminated are not sufficiently potent to evoke behaviour change. There has been an exponential growth in the availability of digital health technologies within the consumer marketplace. This influx of technology has allowed people to self-monitor a plethora of health indices, such as their physical activity, in real-time. However, changing movement behaviours is difficult and often predicated on the assumption that individuals are willing to change their lifestyles today to reduce the risk of developing disease years or even decades later. One approach that may help overcome this challenge is to present physiological feedback in parallel with physical activity feedback. In combination, this approach may help people to observe the acute health benefits of being more physically active and subsequently translate that insight into a more physically active lifestyle. AIMS. Study One aimed to review existing studies employing fMRI to examine neurological responses to health messages pertaining to physical activity, sedentary behaviour, smoking, diet and alcohol consumption to assess the capacity for fMRI to assist in evaluating health behaviours. Study Two aimed to use fMRI to evaluate physical activity, sedentary behaviour and glucose feedback obtained through wearable digital health technologies and to explore associations between activated brain regions and subsequent changes in behaviour. Study Three aimed to explore engagement of people at risk of type 2 diabetes using digital health technologies to monitor physical activity and glucose levels. METHODS. Study One was a systematic review of published studies investigating health messages relating to physical activity, sedentary behaviour, diet, smoking or alcohol consumption using fMRI. Study Two asked adults aged 30-60 years to undergo fMRI whilst presented personalised feedback on their physical activity, sedentary behaviour and glucose levels, following a 14-day wear protocol of an accelerometer, inclinometer and flash glucose monitor. Study Three was a six-week, three-armed randomised feasibility trial for individuals at moderate-to-high risk of developing type 2 diabetes. The study used commercially available wearable physical activity (Fitbit Charge 2) and flash glucose (Freestyle Libre) technologies. Group 1 were offered glucose feedback for 4 weeks followed by glucose plus physical activity feedback for 2 weeks (G4GPA2). Group 2 were offered physical activity feedback for 4 weeks followed by glucose plus physical activity feedback for 2 weeks (PA4GPA2). Group 3 were offered glucose plus physical activity feedback for six weeks (GPA6). The primary outcome for the study was engagement, measured objectively by time spent on the Fitbit app, LibreLink app (companion app for the Freestyle Libre) as well as the frequency of scanning the Freestyle Libre and syncing the Fitbit. RESULTS. For Study One, 18 studies were included in the systematic review and of those, 15 examined neurological responses to smoking related health messages. The remaining three studies examined health messages about diet (k=2) and physical activity (k=1). Areas of the prefrontal cortex and amygdala were most commonly activated with increased activation of the ventromedial prefrontal cortex predicting subsequent behaviour (e.g. smoking cessation). Study Two identified that presenting people with personalised feedback relating to interstitial glucose levels resulted in significantly more brain activation when compared with feedback on personalised movement behaviours (P < .001). Activations within regions of the prefrontal cortex were significantly greater for glucose feedback compared with feedback on personalised movement behaviours. Activation in the subgyral area was correlated with moderate-to-vigorous physical activity at follow-up (r=.392, P=.043). In Study Three, time spent on the LibreLink app significantly reduced for G4GPA2 and GPA6 (week 1: 20.2±20 versus week 6: 9.4±14.6min/day, p=.007) and significantly fewer glucose scans were recorded (week 1: 9.2±5.1 versus week 6: 5.9±3.4 scans/day, p=.016). Similarly, Fitbit app usage significantly reduced (week 1: 7.1±3.8 versus week 6: 3.8±2.9min/day p=.003). The number of Fitbit syncs did not change significantly (week 1: 6.9±7.8 versus week 6: 6.5±10.2 syncs/day, p=.752). CONCLUSIONS. Study One highlighted the fact that thus far the field has focused on examining neurological responses to health messages using fMRI for smoking with important knowledge gaps in the neurological evaluation of health messages for other lifestyle behaviours. The prefrontal cortex and amygdala were most commonly activated in response to health messages. Using fMRI, Study Two was able to contribute to the knowledge gaps identified in Study One, with personalised glucose feedback resulting in a greater neurological response than personalised feedback on physical activity and sedentary behaviour. From this, Study Three found that individuals at risk of developing type 2 diabetes were able to engage with digital health technologies offering real-time feedback on behaviour and physiology, with engagement diminishing over time. Overall, this thesis demonstrates the potential for digital health technologies to play a key role in feedback paradigms relating to chronic disease prevention.

STUDY 1. INTRODUCTION. Insufficient physical activity is a major risk factor for developing type 2 diabetes. Using isotemporal substitution models, the influence of replacing modest durations of sedentary time with physical activity on diabetes risk scores can be studied. The aims of this study were to examine the relationship between diabetes risk scores, sedentary time and physical activity measured using wrist worn accelerometry, and to model the changes in risk scores by reallocating movement behaviours from lower to a higher intensity. METHODS. Data from 251 (93 males; aged 56.7 ± 8.8) participants from a mixed ethnicity cohort from Leicestershire, UK were selected for analysis. The relationship between diabetes risk (using the Leicester Diabetes Risk Assessment Score), physical activity and sedentary time was identified using multiple linear regressions and isotemporal substitution analysis. Models were calculated for main effects and also adjusted for peak oxygen uptake (VO2) and accelerometer wear time. RESULTS. Both unadjusted and adjusted models revealed that diabetes risk was inversely related to sedentary time, and positively related to light and moderate to vigorous physical activity (MVPA) (p < 0.0005). Unadjusted, the replacement of sedentary time with 10 minutes of either light or MVPA resulted in a reduction in diabetes risk score of -0.22 and -0.54, respectively. There was an eight to nine times greater reduction in risk for the same MVPA replacement models when the least active participants were compared to the pooled analysis (3.601 unadjusted). CONCLUSION. Diabetes risk is associated with sedentary time and physical activity estimated from wrist worn accelerometry. The replacement of sedentary time with MVPA is most beneficial for the least active individuals. STUDY 2. INTRODUCTION. Most associations between physical behaviours and health are assessed using intensity and duration based estimations; however, individuals accrue physical activity in differing ways and behavioural profiles have been linked with varying cardiometabolic risk factors. The frequency or regularity of behaviour may hold additional relationships with health, but have not been extensively explored. Accelerometers provide researchers with a large stream of raw data to analyse. The aim of this paper was to calculate a novel method of behavioural regularity called sample entropy from wrist worn accelerometry and to ascertain whether there are associations with cardiometabolic risk factors in adults. METHODS. Data from 290 (107 males; aged 57.0 ± 8.8) participants from a mixed ethnicity cohort from Leicestershire, UK were selected for analysis. Entropy scores were calculated using 60-second count data within MATLAB. The relationship between entropy scores, physical activity, sedentary time and cardiometabolic risk factors was identified using multiple linear regressions. Models were calculated for main effects and also adjusted for age, sex, accelerometer wear time and body mass index (BMI). RESULTS. Sample entropy scores were significantly related to high-density lipoprotein (HDL) cholesterol (b = 0.148, p = 0.042), triglycerides (b = -0.293, p = 0.042) and glycated haemoglobin (HbA1c) (b = -0.225, p = 0.006), even after adjustment for confounding variables. Traditional intensity estimates of physical activity were not associated; however, the frequency of breaks in sedentary time were significantly related to entropy scores (b = 0.004, p = 0.002). CONCLUSION. Using a novel measure of signal complexity, associations have been revealed with cardiometabolic risk factors; however further analysis in a larger, more diverse dataset is required to ascertain the utility of this technique within behavioural research and if so, what constitutes typical/average levels of entropy within a population. STUDY 3. INTRODUCTION. Acute physiological changes such as reductions in postprandial glucose excursions have been demonstrated within experimental studies that have compared being physically active to sedentary conditions. However, for this information to be truly useful, the coupling of behaviour and glucose data in a free-living environment needs to be achieved. The aim of the study was to ascertain if there is a relationship between objectively measured physical activity, sedentary time and glucose variability using glucose monitoring in an adult population. METHODS. Data from 29 participants recruited from a mixed gender sample from Leicestershire, UK were selected for analysis. Physical activity, sedentary time and interstitial glucose was measured continuously over 14 days using an accelerometer and the Freestyle Libre flash glucose monitor. Daily time (minutes) spent sedentary, and in light activity and moderate to vigorous physical activity (MVPA) were regressed against glycaemic variability indices including daily mean (average) glucose, standard deviation and mean amplitude of glycaemic excursions (MAGE). Generalised Estimating Equations were calculated between behaviour and glycaemic variability variables. Models were calculated for main effects and also adjusted for age, gender and accelerometer wear time. RESULTS. Physical activity and sedentary time were associated with measures of glucose variability, however low fitness individuals showed a stronger relationship between MVPA and MAGE (MAGE: whole sample b = -0.002, low fitness b = -0.012. Additionally, after adjustment for covariates, sedentary time was positively associated with a higher daily mean glucose (b = 0.001, p = 0.001) and MAGE (b = 0.002, p < 0.0005) for the low fitness group. MVPA was negatively associated with mean glucose (b = -0.004, p < 0.0005) and MAGE (b = -0.012, p < 0.0005); however, standard deviation of glucose was not associated with behaviour of any intensity. The magnitudes of the relationships were small, although participants were non-diabetics and exhibited relatively good glucose control i.e. minimal fluctuations in daily glucose variability. CONCLUSION. This study shows that sedentary time, physical activity and glucose variability are related. Despite supporting the previous laboratory research, it is uncertain whether any changes in glucose will reliably occur in all individuals. MVPA confers the largest reductions in glucose variability indices, yet as one of the few studies to couple behaviour and glucose data, more research is needed on larger and more diverse samples.

Background: Studies have reported that preschool children may not be sufficiently active according to guidelines. This is worrying because early childhood is a critical period for the establishment of sedentary behaviour (SB) and physical activity (PA) habits, which have immediate and long term influences on health. The majority of evidence on levels, determinants, and health consequences of SB and PA in young children is, however, based on subjective measures in predominately White children aged three years or older. Aims: To 1) assess the feasibility and acceptability of using three different accelerometers in South Asian and White British 2-3 year olds and their parents; 2) calibrate and validate the accelerometers to measure SB and PA in 2-3 year olds; 3) investigate the influence of 5-, 10-, and 15-second epochs on time spent in SB, light PA, and moderate-to-vigorous PA (MVPA) in 2-3 year olds; and 4) assess the feasibility of measuring the habitual SB and PA with the ActiGraph GT3X+ accelerometer in South Asian and White British 2-3 year olds and their parents. Methods: Focus groups were performed with 17 South Asian and White British mothers and the audio-recordings were transcribed verbatim and analysed with thematic analysis (Aim 1). To calibrate the three accelerometers against direct observation (Aim 2), semi-structured activity sessions were run with 18 South Asian and White British 2-3 year olds. Mixed-effects regression and receiver-operating characteristics (ROC) curve analysis were used to generate prediction equations and 5- and 10-second cut-points to assess children s SB and PA. Validity of the generated cut-points against direct observation (Aim 2) was assessed in a separate sample of 20 White British and Black African 2-3 year olds during free-play, using Cohen s kappa, ROC curve analysis, Bland-Altman plots, and Lin s concordance coefficient. Differences in estimated time spent in SB, light PA and MVPA from 5-, 10- and 15-second epochs were tested with repeated-measures ANOVA and paired t-tests in the calibration sample (Aim 3). A pilot study was conducted with 120 South Asian and White British families from a birth cohort study to address aim 4. Study intake and compliance with an 8-day measurement protocol were calculated, and differences between ethnicities were assessed with the Chi-square test. Results: The ActiGraph GT3X+ was the most widely accepted accelerometer, with the least amount of issues raised by mothers. Practical and software issues with the Actiheart and activPAL3 during the calibration phase resulted in insufficient good quality data collected, which made it unfeasible to calibrate both monitors. The overall 5-second Axis1 cut-points for the ActiGraph GT3X+ provided a valid tool to measure the SB and total PA of 2-3 year olds in free-living conditions. Using 10- and 15-second epochs overestimated children s light PA and underestimated time spent in SB and MVPA. Less South Asian than White British families were recruited into the study, and less South Asian than White British children complied with the 8-day measurement protocol. There were no ethnic differences in the number of children and parents providing enough accelerometry data (i.e. ≥ 3 valid days), or the number of parents complying with the measurement protocol. Conclusions: The results demonstrated that it is feasible to use the ActiGraph GT3X+ to assess the habitual SB and PA of a bi-ethnic sample of 2-3 year old children and their parents. The accurate assessment of SB and PA in 2-3 year olds using the overall 5-second Axis1 cut-points developed and validated in this thesis will enable researchers to investigate the levels, determinants, and health consequences of SB and PA. Such research will inform public health policies and interventions to improve children s health.

Introduction: Metabolic syndrome (MetS) is a risk condition describing a clustering of traditional cardiovascular risk factors. A number of risk and protective factors have been associated with MetS, and individuals with MetS are at a higher risk for developing chronic diseases such as diabetes, cancer, and cardiovascular disease. Objective: To contribute to the understanding of MetS in Canada, and to describe how it is a risk state through which material, psychosocial, and behavioural factors associate with chronic diseases. This was examined through three objectives: (i) to describe the prevalence and distribution of MetS; (ii) to examine potential pathways linking income and education with MetS; and (iii) to examine the interplay between non-movement behaviours (NMBs, namely sleep, screen time, and sedentary behaviour) and MetS. Methods: The Canadian Health Measures Survey (2007-2009, 2009-2011, ages 18 and older) was used for all analyses, which include logistic regression, multinomial regression, and calculation of standardized logit coefficients. Results: MetS was prevalent among approximately 20% of Canadian adults. It was significantly associated with chronic diseases, such as diabetes (11.2% vs. 3.4% among those with MetS vs. the general population). A social gradient in MetS was identified, and the behavioural risk factors of alcohol use, smoking, physical inactivity, and screen time were suggested to be partial mediators of this pathway. Findings demonstrated that not adhering to physical activity guidelines (150 minutes or more of moderate-to-vigorous physical activity per week) was associated with increased odds of MetS. A stepwise moderating effect of guideline adherence on screen time and sleep behaviours was demonstrated. Conclusion: MetS is prevalent in Canadian adults, and a high proportion of individuals with MetS have chronic conditions. Addressing the modifiable determinants of physical inactivity, excess screen time, alcohol consumption, and smoking may reduce the social gradient in MetS. Furthermore, adhering to physical activity guidelines may mitigate the associations of NMBs with MetS. The current thesis suggests that healthy behaviours are associated with lower risk for MetS, and therefore, possibly for future chronic disease.

Recent research suggests that sedentary behaviours have detrimental effects on the health and well-being of children, including effects on obesity. Specifically, television viewing is consistently associated with childhood obesity. Two explanations have been proposed: 1) reduced energy expenditure, and 2) increased food intake. However, it has been suggested that the association between television viewing and childhood obesity may be better explained by an increase in energy intake than by a reduction in energy expenditure. To date, children of different weight status have not been compared in their dietary patterns in front of the television, and it is not known if total sedentary time is linked with food intake in children. The objectives of this thesis are: 1) to determine if obese children consume food more frequently while watching television than normal weight children, and 2) to examine which of television viewing or total sedentary time better predicts dietary patterns in children. Overall, our results re-affirm the notion that television viewing is associated with obesity, although physical activity plays a role in this association. Also, children who are obese consume fast food and fruits/vegetables more frequently during television watching than normal weight children. Furthermore, television viewing appears to be a better predictor of dietary patterns in children than overall sedentary time. Globally, these results provide evidence for the deleterious effects of television viewing on children’s dietary patterns and justification for future intervention studies designed to reduce television viewing in children with obesity.

Yes / To investigate factors associated with movement behaviours among White British (WB) and South Asian (SA) children aged 6-8 years during school terms and holidays. Cross-sectional. Three primary schools from the Bradford area, UK. One hundred and sixty WB and SA children aged 6-8 years. Sedentary behaviour (SB), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) measured by accelerometry during summer, winter and spring and during school terms and school holidays. Data were analysed using multivariate mixed-effects multilevel modelling with robust SEs. Factors of interest were ethnicity, holiday/term, sex, socioeconomic status (SES), weight status, weekend/weekday and season. One hundred and eight children (67.5%) provided 1157 valid days of data. Fifty-nine per cent of children were WB (n=64) and 41% (n=44) were SA. Boys spent more time in MVPA (11 min/day, p=0.013) compared with girls and SA children spent more time in SB (39 min, p=0.017) compared with WB children in adjusted models. Children living in higher SES areas were more sedentary (43 min, p=0.006) than children living in low SES areas. Children were more active during summer (15 min MVPA, p<0.001; 27 LPA, p<0.001) and spring (15 min MVPA, p=0.005; 38 min LPA, p<0.001) and less sedentary (−42 min and −53 min, p<0.001) compared with winter. Less time (8 min, p=0.012) was spent in LPA during school terms compared with school holidays. Children spent more time in MVPA (5 min, p=0.036) during weekend compared with weekdays. Overweight and obese children spent more time in LPA (21 min, p=0.021) than normal-weight children. The results of our study suggest that significant child level factors associated with movement behaviours are ethnicity, sex, weight-status and area SES. Significant temporal factors are weekends, school holidays and seasonality. Interventions to support health enhancing movement behaviours may need to be tailored around these factors.

Bakgrund: Fysisk aktivitet förbättrar psykiskt och fysiskt välmående. Fysisk inaktivitet och stillasittande är ett växande samhällsproblem där fysiskt inaktiva arbeten är vanliga. Ett annat samhällsproblem är stressrelaterade besvär. Fysisk aktivitet kan minska stressnivåer och för att utföra fysisk aktivitet är motivation en viktig faktor. Det föreligger en kunskapslucka kring hur fysisk aktivitetsnivå, stillasittande, motivation och stressnivåer hos personer med fysiskt inaktiva arbeten är.  Syfte: Beskriva fysisk aktivitetsnivå, stillasittande, motivationsfaktorer samt stressnivåer hos individer med ett fysiskt inaktivt arbete samt undersöka könsskillnader. Även studera samband mellan stress och fysisk aktivitetsnivå respektive stress och stillasittande.  Metod: En kvantitativ enkätstudie med deskriptiv, korrelerande och jämförande design genomfördes. Socialstyrelsens indikatorfrågor om fysisk aktivitet och stillasittande, BREQ-2 om motivation till fysisk aktivitet och PSS-10 om upplevd stress besvarades av 53 individer från tre arbetsplatser med fysiskt inaktiva arbeten. Data analyserades med icke-parametrisk statistik.  Resultat: 52 deltagare inkluderas, 50% var kvinnor. Deltagarna rapporterade i genomsnitt 285 aktivitetsminuter/vecka, 660 stillasittande minuter/dygn, måttlig grad av upplevd stress och 38% hade inre reglering som motivationsfaktor till fysisk aktivitet. Det förelåg små positiva icke-signifikanta samband mellan stress och fysisk aktivitet respektive stress och stillasittande. Det förelåg inga signifikanta könsskillnader gällande någon undersökt variabel.  Slutsats: Individerna var fysiskt aktiva, motiverades av inre reglering och var mycket stillasittande. Resultaten belyser vikten av att ta stillasittande och psykosociala faktorer i beaktning vid kartläggning av fysisk aktivitetsnivå. Det behövs fler studier som säger något om könsskillnader gällande undersökta variabler. / Background: Physical activity improves mental and physical health. Physical inactivity and sedentary is an expanding societal problem where physically inactive professions are common. Another societal problem is stress-related disorders. Physical activity can reduce stress levels and motivation is important for physical activity. There is a knowledge gap regarding physical activity, sedentary, motivation and stress in individuals with physically inactive professions.  Purpose: Describe physical activity, sedentary, motivation and stress in individuals with physically inactive professions and examine gender differences. Also study correlation between stress and physical activity and stress and sedentary behaviour.  Method: A quantitative questionnaire study with descriptive, correlative and comparative design was conducted. The National Board of Health and Welfare's indicator questions about physical activity and sedentary, BREQ-2 about motivation for physical activity and PSS-10 about perceived stress were answered by 53 individuals from three workplaces with physically inactive professions. The data were analysed using non-parametric statistics.  Results: 52 participants were included, 50% were women. The participants reported 285 activity minutes/week, 660 sedentary minutes/day, moderate levels of perceived stress and 38% had intrinsic regulation as motivational factor for physical activity. Small positive non-significant correlations were seen between stress and physical activity and stress and sedentary. There were no significant gender differences regarding all variables.  Conclusion: The individuals were physically active, motivated by intrinsic regulation and had many sedentary minutes/day. The results highlight the importance of taking sedentary and psychosocial factors into consideration when identifying physical activity. More studies are required that examine gender differences regarding examined variables.

High levels of sedentary behaviour (SB) and low levels of physical activity (PA) in primary school children are a health concern especially for the South Asians (SA) because of increased cardiovascular risk. The study investigated ethnic differences in movement behaviours among primary school children in three studies: 1) inclinometer and accelerometer measured movement behaviours in White British (WB) vs. SA 6-8-year-old children; 2) qualitative studies with children, parents and teachers explored barriers and facilitators to reducing SB; and, 3) accelerometer measured movement behaviours in children aged 8-11-years. The inclinometer outcomes were: total SB, SB from bouts >30 minutes and breaks in SB, while accelerometry considered: SB, light PA and moderate to-vigorous PA and counts per minute. 525 children, eight parents and six teachers participated. No ethnic differences were identified in inclinometer outcomes except for SB breaks. SA children had 25 fewer breaks compared to WB. Accelerometry identified higher SB for SA children vs. WB in study one but no ethnic differences in study three; a pattern for higher SB/lower PA for SA children vs. WB was consistent in studies. Reasons for engagement in SB included: knowledge and beliefs about SB, child characteristics, cultural norms, parenting, educational system and the built environment. A large proportion of movement behaviour interventions components were related to education and policy. Children’s levels of SB were similar to office workers regardless of ethnicity. Interventions to reduce SB need to consider SB breaks and PA, especially for SA children who were less active and more sedentary than WB.