title: Breaking up prolonged sitting reduces resting blood pressure in overweight/obese adults.
abstract: OBJECTIVE
  To compare the effect of 7 h of prolonged sitting on resting blood pressure with a similar duration of sitting combined with intermittent brief bouts of light-intensity or moderate-intensity physical activity.
  
  
  RESULTS
  Overweight/obese adults (n = 19; aged 45-65 years) were recruited for a randomized three-treatment crossover trial with a one-week washout between treatments: 1) uninterrupted sitting; 2) sitting with 2 min bouts of light-intensity walking at 3.2 km/h every 20 min; and, 3) sitting with 2 min bouts of moderate-intensity walking at between 5.8 and 6.4 km/h every 20 min. After an initial 2 h period seated, participants consumed a test meal (75 g carbohydrate, 50 g fat) and completed each condition over the next 5 h. Resting blood pressure was assessed oscillometrically every hour as a single measurement, 5 min prior to each activity bout. GEE models were adjusted for sex, age, BMI, fasting blood pressure and treatment order. After adjustment for potential confounding variables, breaking up prolonged sitting with light and moderate-intensity activity breaks was associated with lower systolic blood pressure [light: 120 ± 1 mmHg (estimated marginal mean ± SEM), P = 0.002; moderate: 121 ± 1 mmHg, P = 0.02], compared to uninterrupted sitting (123 ± 1 mmHg). Diastolic blood pressure was also significantly lower during both of the activity conditions (light: 76 ± 1 mmHg, P = 0.006; moderate: 77 ± 1 mmHg, P = 0.03) compared to uninterrupted sitting (79 ± 1 mmHg). No significant between-condition differences were observed in mean arterial pressure or heart rate.
  
  
  CONCLUSIONS
  Regularly breaking up prolonged sitting may reduce systolic and diastolic blood pressure.
  
  
  BACKGROUND
  ACTRN12609000656235 (http://www.anzctr.org.au) TRIAL REGISTRATION DATE: August 4th 2009.
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia. Electronic address: robyn.larsen@bakeridi.edu.au.
authors.forename: R N
authors.initials: RN
authors.lastname: Larsen
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia; Department of Physiology, Monash University, Melbourne, Australia; Department of Physiology, The University of Melbourne, Melbourne, Australia.
authors.forename: B A
authors.initials: BA
authors.lastname: Kingwell
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Sethi
authors.affiliation: School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia; Institute of Human Performance, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: E
authors.initials: E
authors.lastname: Cerin
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia; Cancer Prevention Research Centre, School of Population Health, The University of Queensland, Brisbane, Australia; Melbourne School of Population Health, The University of Melbourne, Melbourne, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Owen
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia; School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; School of Sport Science, Exercise and Health, The University of Western Australia, Perth, Australia.
authors.forename: D W
authors.initials: DW
authors.lastname: Dunstan
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D015992:Body Mass Index; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D050177:Overweight / Q000378:metabolism*; D057185:Sedentary Behavior; D014280:Triglycerides / Q000097:blood; D055105:Waist Circumference; D016138:Walking / Q000502:physiology*
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides
keywords: Hypertension; Obesity; Physical activity; Sedentary behavior