Breaks in sedentary time: beneficial associations with metabolic risk.
OBJECTIVE
Total sedentary (absence of whole-body movement) time is associated with obesity, abnormal glucose metabolism, and the metabolic syndrome. In addition to the effects of total sedentary time, the manner in which it is accumulated may also be important. We examined the association of breaks in objectively measured sedentary time with biological markers of metabolic risk.


METHODS
Participants (n = 168, mean age 53.4 years) for this cross-sectional study were recruited from the 2004-2005 Australian Diabetes, Obesity and Lifestyle study. Sedentary time was measured by an accelerometer (counts/minute(-1) < 100) worn during waking hours for seven consecutive days. Each interruption in sedentary time (counts/min > or = 100) was considered a break. Fasting plasma glucose, 2-h plasma glucose, serum triglycerides, HDL cholesterol, weight, height, waist circumference, and resting blood pressure were measured. MatLab was used to derive the breaks variable; SPSS was used for the statistical analysis.


RESULTS
Independent of total sedentary time and moderate-to-vigorous intensity activity time, increased breaks in sedentary time were beneficially associated with waist circumference (standardized beta = -0.16, 95% CI -0.31 to -0.02, P = 0.026), BMI (beta = -0.19, -0.35 to -0.02, P = 0.026), triglycerides (beta = -0.18, -0.34 to -0.02, P = 0.029), and 2-h plasma glucose (beta = -0.18, -0.34 to -0.02, P = 0.025).


CONCLUSIONS
This study provides evidence of the importance of avoiding prolonged uninterrupted periods of sedentary (primarily sitting) time. These findings suggest new public health recommendations regarding breaking up sedentary time that are complementary to those for physical activity.
Healy
Genevieve N
GN
Cancer Prevention Research Centre, School of Population Health, The University of Queensland, Brisbane, Australia. g.healy@uq.edu.au
Dunstan
David W
DW
Salmon
Jo
J
Cerin
Ester
E
Shaw
Jonathan E
JE
Zimmet
Paul Z
PZ
Owen
Neville
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D001786:Blood Glucose / Q000378:metabolism; D049628:Body Size; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D003925:Diabetic Angiopathies / Q000453:epidemiology; D003928:Diabetic Nephropathies / Q000453:epidemiology; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009765:Obesity / Q000453:epidemiology; D012146:Rest / Q000502:physiology*; D012307:Risk Factors; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D014937:Work
D001786:Blood Glucose; D014280:Triglycerides