BackgroundThere is a growing body of research into the total amount and patterns of sitting, standing and stepping in office-based workers and few studies using objectively measured sitting and standing. Understanding these patterns may identify daily times opportune for interventions to displace sitting with activity.MethodsA sample of office-based workers (n = 164) residing in England were fitted with thigh-worn ActivPal accelerometers and devices were worn 24 hours a day for five consecutive days, always including Saturday and Sunday and during bathing and sleeping. Daily amounts and patterns of time spent sitting, standing, stepping and step counts and frequency of sit/stand transitions, recorded by the ActivPal accelerometer, were reported.ResultsTotal sitting/standing time was similar on weekdays (10.6/4.1 hrs) and weekends (10.6/4.3 hrs). Total step count was also similar over weekdays (9682 ± 3872) and weekends (9518 ± 4615). The highest physical activity levels during weekdays were accrued at 0700 to 0900, 1200 to 1400, and 1700 to 1900; and during the weekend at 1000 to 1700. During the weekday the greatest amount of sitting was accrued at 0900 to 1200, 1400 to 1700, and 2000 to 2300, and on the weekend between 1800 and 2300. During the weekday the greatest amount of standing was accrued between 0700 and 1000 and 1700 and 2100, and on the weekend between 1000 and 1800. On the weekday the highest number of sit/stand transitions occurred between 0800 to 0900 and remained consistently high until 1800. On the weekend, the highest number occurred between 1000 to 1400 and 1900 to 2000.ConclusionOffice based-workers demonstrate high levels of sitting during both the working week and weekend. Interventions that target the working day and the evenings (weekday and weekend) to displace sitting with activity may offer most promise for reducing population levels of sedentary behaviour and increasing physical activity levels, in office-based workers residing in England.
Intervention efforts to increase occupational physical activity and reduce sedentary time may be most effective when targeted at white-collar workers. Research is needed to identify additional modifiable correlates of occupational physical activity and sedentary behaviour, in white-collar workers.
Simulations using CONTAM (a validated multi-zone indoor air quality (IAQ) model) were employed to predict indoor exposure to PM2.5 in London dwellings in both the present day housing stock and the same stock following energy efficient refurbishments to meet greenhouse gas emissions reduction targets for 2050. To achieve these targets, measures were specified that reduced building permeability to 3m 3 m-2 hr-1 at 50 Pa, combined with the introduction of mechanical ventilation and heat recovery (MVHR) systems. It was assumed that the mean current outdoor PM2.5 concentration of 13μg.m-3 , decreased to 9μg.m-3 by 2050 due to emission control policies. Proper installation of MVHR systems with permeability reduction is associated with appreciable reductions in PM2. 5 exposure in both smoking and non-smoking dwellings. Modelling of the future scenario for nonsmoking dwellings predicts a reduction in annual average indoor exposure to PM2.5 of 24.0μg.m-3 (from 28.4 to 4.4μg.m 3) for a typical household member and a larger reduction of 52.8μg.m-3 (from 60.5 to 7.7μg.m3) for members exposed primarily to cooking-related particle emissions in the kitchen. Reductions in envelope permeability, without mechanical ventilation, produced a small increase (+5.4μg.m-3) in indoor PM2.5 concentrations. These estimates of changes in PM2.5 exposure were sensitive to assumptions about occupant behaviour, ventilation system usage and the distribution of input variables (+72% for non-smoking and +107% in smoking residences) but, if realised would result in significant health benefits.
Domestic winter indoor temperatures in the USA, UK and other developed countries appear to be following an upwards trend. This review examines evidence of a causal link between thermal exposures and increases in obesity prevalence, focusing on acute and longer-term biological effects of time spent in thermal comfort compared with mild cold. Reduced exposure to seasonal cold may have a dual effect on energy expenditure, both minimizing the need for physiological thermogenesis and reducing thermogenic capacity. Experimental studies show a graded association between acute mild cold and human energy expenditure over the range of temperatures relevant to indoor heating trends. Meanwhile, recent studies of the role of brown adipose tissue (BAT) in human thermogenesis suggest that increased time spent in conditions of thermal comfort can lead to a loss of BAT and reduced thermogenic capacity. Pathways linking cold exposure and adiposity have not been directly tested in humans. Research in naturalistic and experimental settings is needed to establish effects of changes in thermal exposures on weight, which may raise possibilities for novel public health strategies to address obesity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.