title: Impact on hemostatic parameters of interrupting sitting with intermittent activity.
abstract: BACKGROUND
  Excessive sitting has been associated with an elevated risk of vascular conditions, particularly venous thrombosis. Interrupting sitting time with intermittent physical activity can reduce venous stasis; however, impacts on other aspects of thrombogenesis are less understood.
  
  
  OBJECTIVE
  To examine the effects of interrupting sitting time on blood coagulation and blood volume parameters in sedentary, middle-age, overweight/obese adults (11 men and 8 women; age = 53.8 ± 4.9 yr, body mass index = 31.2 ± 4.1 kg · m(-2); mean ± SD).
  
  
  METHODS
  The randomized three-period, three-treatment acute crossover trial consisted of uninterrupted sitting and sitting interrupted by 2-min bouts of either light- or moderate-intensity treadmill walking every 20 min. In each trial condition, blood samples were collected at baseline before the consumption of a standardized meal (-2 h) and postintervention (5 h).
  
  
  RESULTS
  Plasma fibrinogen increased from baseline with uninterrupted sitting (0.24 g · L(-2), 95% confidence interval = 0.13-0.34, P < 0.001). Light-intensity but not moderate-intensity activity breaks attenuated the increase by 0.17 g · L(-1) (95% confidence interval = 0.01-0.32, P < 0.05). There were no between-condition differences in prothrombin time, activated partial thromboplastin time, von Willebrand factor, D-dimer, or platelet count. Uninterrupted sitting reduced plasma volume and increased hematocrit, hemoglobin, and red blood cell count; effects attenuated by both light- and moderate-intensity breaks (P < 0.05). White blood cell count increased with uninterrupted sitting and further increased with moderate-intensity breaks. Mean platelet volume increased with moderate-intensity but not light-intensity breaks or uninterrupted sitting.
  
  
  CONCLUSIONS
  Uninterrupted sitting increased fibrinogen and reduced plasma volume, with associated increases in hemoglobin and hematocrit. Activity breaks attenuated these responses, indicative of an ameliorating influence on the procoagulant effects of uninterrupted sitting.
authors: Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
authors: Bethany J
authors: BJ
authors: Howard
authors: Steve F
authors: SF
authors: Fraser
authors: Parneet
authors: P
authors: Sethi
authors: Ester
authors: E
authors: Cerin
authors: Marc T
authors: MT
authors: Hamilton
authors: Neville
authors: N
authors: Owen
authors: David W
authors: DW
authors: Dunstan
authors: Bronwyn A
authors: BA
authors: Kingwell
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001780:Blood Coagulation Tests; D001810:Blood Volume; D018592:Cross-Over Studies; D004906:Erythrocyte Count; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000503:physiopathology; D050177:Overweight / Q000097:blood / Q000503:physiopathology*; D010976:Platelet Count; D057185:Sedentary Behavior; D019851:Thrombophilia / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D016138:Walking / Q000502:physiology*
chemical_list: D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; D006454:Hemoglobins; C036309:fibrin fragment D; D005340:Fibrinogen