School of Exercise and Nutrition Sciences

ReviewToo much sitting A health hazardDavid W. Dunstan a,b,c,d,e,*, Bethany Howard a, Genevieve N. Healy a,b, Neville Owen a,b,ca Baker IDI Heart and Diabetes Institute, Melbourne, Australia b School of Population Heath, The University of Queensland, Brisbane, Australia c School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia d School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia e ECU Health and Wellness Institute, Edith Cowan University, Perth, AustraliaContents1. Sedentary behavior and cardio-metabolic health emergence of a new paradigm. . . . . . . . . . . . . . . . . . . . . . . . . . . 3692. The particular health hazards of too much sitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3703. Sedentary behavior and premature mortality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3714. Prolonged unbroken sitting is a contributor to poor health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3715. Experimental models addressing the metabolic consequences of prolonged, unbroken sedentary time . . . . . . . . . . 3726. Public health and clinical implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3737. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 9 7 ( 2 0 1 2 ) 3 6 8 3 7 6a r t i c l e i n f oArticle history:Received 17 May 2012Accepted 17 May 2012Published on line 9 June 2012Keywords:Sitting timeBreaks in sedentary timeTV viewing timeSedentary behaviorMortalitya b s t r a c tIn contemporary society, prolonged sitting has been engineered into our lives across manysettings, including transportation, the workplace, and the home. There is new evidence thattoo much sitting (also known as sedentary behavior which involves very low energyexpenditure, such as television viewing and desk-bound work) is adversely associated withhealth outcomes, including cardio-metabolic risk biomarkers, type 2 diabetes and premature mortality. Importantly, these detrimental associations remain even after accountingfor time spent in leisure time physical activity. We describe recent evidence from epidemiological and experimental studies that makes a persuasive case thattoo much sitting shouldnow be considered an important stand-alone component of the physical activity and healthequation, particularly in relation to diabetes and cardiovascular risk. We highlight directions for further research and consider some of the practical implications of focusing on toomuch sitting as a modifiable health risk.