Objectively Measured Sedentary and Physical Activity Behavior Across the Life Span

Introduction Recent research shows that too much sitting has negative effects on health and well-being independently from people meeting the current physical activity (PA) recommendations [1]. However sedentary behavior (SB) is still an understudied topic. The aim of this study was to objectively investigate the time spent in sedentary and PA behaviors in several cohorts of Belgian toddlers, children, adolescents and adults. Further we wanted to examine if the amount of time spent in SB differed between these age groups (cohorts) and according to gender and BMI subgroups.

Methods To objectively assess SB and PA a total of 2083 Belgian preschoolers, primary and secondary schoolchildren, and adults (age range 3-64, 52% female, 75% normal BMI) wore an Actigraph accelerometer model 7164 for at least 3 days (including one weekend day). To calculate time spent in SB and moderate-to-vigorous intensity PA (MVPA), cut-points of <100 counts/min and >2000 counts/min were used respectively. Further participants’ height and weight were assessed and participants were categorised as normal weight, overweight or obese using age-specific BMI cut-offs.

Results Analyses of the accelerometer data showed that for the total sample participants spent 57% of their waking hours (7,8 hours/day) in SB, 38% in light intensity PA and 5% in MVPA. The amount of time spent in SB significantly differed between the cohorts groups according to gender, but not according to BMI subgroups. In women lower levels of SB were found in preschoolers (51%) and primary schoolgirls (53%), compared to adults (56%) and secondary schoolgirls (61%). In men, the older the cohort group, the more time they spent in SB, with a maximum amount of 59% in the adult group.

Discussion and Conclusion Similar with the results in Swedish (55%) [2] and US adults (55%) [3], Belgian populations spent most of their waking hours sedentary (57%). Different levels were shown between cohort groups according to gender, with girls at secondary school being most sedentary (61%). Large longitudinal studies using objective measurements are needed to investigate patterns of SB across the lifespan.

References [1] Healy,G.N., Dunstan,D.W., Salmon,J., Cerin,E., Shaw,J.E., Zimmet,P.Z., and Owen,N..Objectively measured light-intensity physical activity is independently associated with 2-h plasma glucose. Diabetes Care, 2007;30: 1384-1389. [2] Hagstromer,M., Oja,P., and Sjostrom,M.. Physical activity and inactivity in an adult population assessed by accelerometry. Med Sci. Sports Exerc, 2007; 39: 1502-1508. [3] Matthews,C.E., Chen,K.Y., Freedson,P.S., Buchowski,M.S., Beech,B.M., Pate,R.R., and Troiano,R.P.. Amount of time spent in sedentary behaviors in the United States, 2003-2004. Am J Epidemiol, 2008;167: 875-881.