Sedentary time (too much sitting) is increasingly being recognized as a distinct health risk behavior. This paper reviews the reliability and validity of self-reported and device-based sedentary time measures and provides recommendations for their use in population-based studies. The focus is on instruments that have been used in free-living, population-based research in adults. Data from the 2003–2006 National Health and Nutrition Examination Survey are utilized to compare the descriptive epidemiology of sedentary time that arises from the use of different sedentary time measures. A key recommendation from this review is that, wherever possible, population-based monitoring of sedentary time should incorporate both self-reported measures (to capture important domain- and behavior-specific sedentary time information) and device-based measures (to measure both total sedentary time and patterns of sedentary time accumulation).

BackgroundTo examine sedentary time, prolonged sedentary bouts and physical activity in Australian employees from different workplace settings, within work and non-work contexts.MethodsA convenience sample of 193 employees working in offices (131), call centres (36) and customer service (26) was recruited. Actigraph GT1M accelerometers were used to derive percentages of time spent sedentary (<100 counts per minute; cpm), in prolonged sedentary bouts (≥20 minutes or ≥30 minutes), light-intensity activity (100–1951 cpm) and moderate-to-vigorous physical activity (MVPA; ≥1952 cpm). Using mixed models adjusted for confounders, these were compared for: work days versus non-work days; work hours versus non-work hours (work days only); and, across workplace settings.ResultsWorking hours were mostly spent sedentary (77.0%, 95%CI: 76.3, 77.6), with approximately half of this time accumulated in prolonged bouts of 20 minutes or more. There were significant (p<0.05) differences in all outcomes between workdays and non-work days, and, on workdays, between work- versus non-work hours. Results consistently showed “work” was more sedentary and had less light-intensity activity, than “non-work”. The period immediately after work appeared important for MVPA. There were significant (p<0.05) differences in all sedentary and activity outcomes occurring during work hours across the workplace settings. Call-centre workers were generally the most sedentary and least physically active at work; customer service workers were typically the least sedentary and the most active at work.ConclusionThe workplace is a key setting for prolonged sedentary time, especially for some occupational groups, and the potential health risk burden attached requires investigation. Future workplace regulations and health promotion initiatives for sedentary occupations to reduce prolonged sitting time should be considered.

Limited evidence was found to support a positive relationship between occupational sitting and health risks. The heterogeneity of study designs, measures, and findings makes it difficult to draw definitive conclusions at this time.

Time spent in non-occupational sedentary behaviours (particularly television viewing time) is associated with excess adiposity and an increased risk of metabolic disorders among adults; however, there are no reviews of the validity and reliability of assessing these behaviours. This paper aims to document measures used to assess adults' time spent in leisure-time sedentary behaviours and to review the evidence on their reliability and validity. Medline, CINAHL and Psych INFO databases and reference lists from published papers were searched to identify studies in which leisure-time sedentary behaviours had been measured in adults. Sixty papers reporting measurement of at least one type of leisure-time sedentary behaviour were identified. Television viewing time was the most commonly measured sedentary behaviour. The main method of data collection was by questionnaire. Nine studies examined reliability and three examined validity for the questionnaire method of data collection. Test-retest reliabilities were predominantly moderate to high, but the validity studies reported large differences in correlations of self-completion questionnaire data with the various referent measures used. To strengthen future epidemiological and health behaviour studies, the development of reliable and valid self-report instruments that cover the full range of leisure-time sedentary behaviour is a priority.

OBJECTIVES:To examine associations of self-reported television (TV) viewing time and overall sitting time with the metabolic syndrome and its components. DESIGN:Cross-sectional. SETTING:Population-based sample of older men and women living in Australia.PARTICIPANTS: 1,958 participants from the Australian Diabetes Obesity and Lifestyle (AusDiab) study (aged ≥ 60 years, mean age 69, 54% women). MEASUREMENTS:Self-reported TV viewing time and overall sitting time were collected by interviewer-administered questionnaire. The metabolic syndrome was defined according to the revised International Diabetes Federation criteria. RESULTS:Compared to those in the lowest quartile, the OR (95% CI) of the metabolic syndrome for men and women in the highest quartile of TV viewing time were 1.42 (0.93-2.15) and 1.42 (1.01-2.01) respectively, and 1.57 (1.02-2.41) for men and 1.56 (1.09-2.24) for women in the highest quartile of overall sitting time. TV viewing time was associated with reduced high-density lipoprotein cholesterol (HDL-C) levels, and glucose intolerance in women only. Overall sitting time was detrimentally associated with an increased risk of raised triglyceride levels (men and women), abdominal obesity (women only), and reduced HDL-C levels (men only). All models were adjusted for age, education, physical activity, self-rated health, employment, diet, smoking, alcohol intake, and hormone replacement therapy / estrogen use (women only) CONCLUSION: For older adults, high levels of sedentary behavior were associated with an increased prevalence of the metabolic syndrome; reducing prolonged overall sitting time may be a feasible way to improve their metabolic health.

The summary measure of total sedentary time has good repeatability and modest validity and is sufficiently responsive to change suggesting that it is suitable for use in interventions with older adults.

Methods: An interviewer-administered questionnaire was used to assess workplace sitting time (hrs/day) and breaks from sitting per hour at work in a convenience sample of 121 full-time workers (36% men, mean age: 37 years, 53% office based). These self-report measures were compared to accelerometer-derived sedentary time (hrs/day <100 counts/min) and breaks per sedentary hour (number of times counts ≥100/min) during work hours. Conclusions:This study is the first to examine the criterion validity of an intervieweradministered questionnaire measure of workplace sitting time and breaks in sitting time using objective criterion measures. The workplace sitting measure has acceptable properties for use in observational studies concerned with sedentary behavior in groups of workers; however, the 4 wide limits of agreement suggest caution in estimating individuals' sitting time with high precision. Using self-report measures to capture patterns of workplace sitting (such as breaks in sitting time) requires further development.

Word Count: 193 words 10 11 Manuscript Word Count: 2,400 words 12 13 Abstract 1 2Background: Sedentary behaviors, particularly television viewing (TV) time, are associated 3 with adverse health outcomes in adults, independent of physical activity levels. These 4 associations are stronger and more consistent for women than for men. 5 6 Methods: Multivariate regression models examined the socio-demographic correlates of two 7 categories of TV time (≥ 2 hours/day; and ≥ 4 hours/day); in a large, population-based sample 8 of Australian adults (4,950 men, 6,001 women; mean age 48.1 years, range 25 to 91) who 9 participated in the 1999/2000 Australian Diabetes, Obesity and Lifestyle (AusDiab) study.10 11 Results: Some 46% of men and 40% of women watched ≥ 2 hours TV/day; 9% and 6% 12 respectively watched ≥ 4 hours/day. For both men and women, ≥ 2 hours TV/day was 13 associated with less than tertiary education, living outside of state capital cities, and having 14 no paid employment. For women, mid and older age (45-64 and 65+) were also significant 15 correlates of ≥ 2 hours TV/day. Similar patterns of association were observed in those 16 viewing ≥ 4 hours/day. 17 18 Conclusions: Prolonged TV time is associated with indices of social disadvantage and older 19 age. These findings can inform the understanding of potential contextual influences and guide 20 preventive initiatives.