Patterns of sedentary behavior in overweight and obese women.

Objectives: Few studies have objectively quantified sedentary behavior, particularly in special population subgroups. This study quantified the volume of and breaks from sedentary behavior in a sample of overweight and obese, primarily African American, women.
Design: Cross-sectional.
Setting: 18 census tracts in Columbia, South Carolina with higher than state and national poverty levels.
Participants: 197 overweight/obese women (87% African American). Mean age 38.3 +/- 7.6 years, mean body mass index 40.6 +/- 8.8 kg/m2.
Main Outcomes Measures: Using a cut point of < 100 counts/minute, estimated daily averages of: 1) total volume, 2) > or = 10, 30, and 60-minute bouts, and 3) patterns of sedentary behavior according to time of day and day of the week were computed. Total breaks, or interruptions, in sedentary time were also calculated.
Results: Participants were sedentary 64.1% of the day, engaging in 10.5 +/- 2.8 daily bouts of sedentary behavior per hour of sedentary time; each bout lasted approximately 6.4 +/- 1.7 minutes. All participants engaged in > or = 1 daily bout of sedentary behavior > or = 10 and > or = 30 minutes, and most (83%) engaged in > or = 1 bout > or = 60 minutes. Participants were slightly more sedentary during the evening (6 pm-midnight) and on weekdays. On average, participants took 90.9 +/- 16.0 breaks from sedentary behavior; each break lasted 3.3 +/- .8 minutes.
Conclusions: Women engaged in more sedentary behavior than that reported in national data sets. In an effort to improve public health, efforts should not only focus on increasing physical activity, but also on decreasing time spent sedentary.