title: Objective physical activity accumulation in bouts and nonbouts and relation to markers of obesity in US adults.
abstract: BACKGROUND
  Little is known about the relation between duration of physical activity and obesity. The objective of this study was to compare the effects of physical activity in bouts (> or = 10 minutes) to the effects of physical activity in nonbouts (<10 minutes) on markers of obesity.
  
  
  METHODS
  We used data from the 2003-2004 National Health and Nutrition Examination Survey on body mass index, waist circumference, and objectively determined physical activity levels for 3,250 adults aged 18 years or older. After controlling for relevant confounding variables, we performed multiple linear regression analyses to predict body mass index and waist circumference for bout and nonbout minutes of moderate- to vigorous-intensity physical activity (MVPA) and for bout and nonbout accelerometer counts of physical activity.
  
  
  RESULTS
  MVPA bout minutes and MVPA nonbout minutes are independently associated with body mass index and waist circumference, after controlling for confounding variables. The strength of the association between lower body mass index and MVPA bout minutes (beta = -0.04, P <.001) was nearly 4 times greater than for MVPA nonbout minutes (beta = -0.01, P = .06). For smaller waist circumference the association was nearly 3 times greater for MVPA bout minutes (beta = -0.09, P <.001) than for MVPA nonbout minutes (beta = -0.03, P = .01). Bout minutes of physical activity were at a higher intensity of activity compared with nonbout minutes of physical activity.
  
  
  CONCLUSIONS
  Accumulating MVPA in nonbouts may be a beneficial starting point for individuals to increase physical activity levels and decrease body mass index and waist circumference. However, bouts of physical activity lasting > or = 10 minutes may be a more time-efficient strategy to decrease body mass index and waist circumference.
authors.affiliation: Department of Human Movement Sciences, The University of Wisconsin-Milwaukee, Enderis Hall Room 435, PO Box 413, Milwaukee, WI 53201-0413, USA. sstrath@uwm.edu
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Strath
authors.forename: Robert G
authors.initials: RG
authors.lastname: Holleman
authors.forename: David L
authors.initials: DL
authors.lastname: Ronis
authors.forename: Ann M
authors.initials: AM
authors.lastname: Swartz
authors.forename: Caroline R
authors.initials: CR
authors.lastname: Richardson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009316:National Institutes of Health (U.S.); D009765:Obesity / Q000453:epidemiology / Q000517:prevention & control*; D012044:Regression Analysis; D014481:United States / Q000453:epidemiology; D055105:Waist Circumference
references.citation: JAMA. 1999 Oct 27;282(16):1554-60
references.pmid: 10546695
references.citation: Psychiatr Clin North Am. 2005 Mar;28(1):141-50, ix
references.pmid: 15733616
references.citation: Med Sci Sports Exerc. 2005 Nov;37(11 Suppl):S512-22
references.pmid: 16294114
references.citation: Endocrinol Metab Clin North Am. 2003 Dec;32(4):967-80
references.pmid: 14711070
references.citation: Int J Obes Relat Metab Disord. 1995 Dec;19(12):893-901
references.pmid: 8963358
references.citation: Metabolism. 2002 Dec;51(12):1528-33
references.pmid: 12489063
references.citation: Int J Obes (Lond). 2007 May;31(5):797-804
references.pmid: 17047641
references.citation: Scand J Med Sci Sports. 2003 Oct;13(5):284-92
references.pmid: 14507293
references.citation: Am Heart J. 2006 Mar;151(3):625-7
references.pmid: 16504623
references.citation: J Womens Health (Larchmt). 2006 Mar;15(2):202-10
references.pmid: 16536684
references.citation: World Health Organ Tech Rep Ser. 2000;894:i-xii, 1-253
references.pmid: 11234459
references.citation: J Am Diet Assoc. 2005 May;105(5 Suppl 1):S35-43
references.pmid: 15867894
references.citation: Am J Public Health. 1994 Jul;84(7):1086-93
references.pmid: 8017530
references.citation: Am J Clin Nutr. 1996 Nov;64(5):685-93
references.pmid: 8901786
references.citation: Int J Obes Relat Metab Disord. 1997 Jul;21(7):587-93
references.pmid: 9226490
references.citation: JAMA. 2006 Apr 5;295(13):1549-55
references.pmid: 16595758
references.citation: JAMA. 1999 Jan 27;281(4):335-40
references.pmid: 9929086
references.citation: JAMA. 1999 Oct 27;282(16):1519-22
references.pmid: 10546690
references.citation: Med Sci Sports Exerc. 2004 May;36(5):911-4
references.pmid: 15126729
references.citation: JAMA. 1995 Feb 1;273(5):402-7
references.pmid: 7823386
references.citation: Scand J Med Sci Sports. 2002 Apr;12(2):99-105
references.pmid: 12121427
references.citation: Am J Clin Nutr. 2002 Apr;75(4):683-8
references.pmid: 11916754
references.citation: Prev Chronic Dis. 2005 Apr;2(2):A17
references.pmid: 15888228
references.citation: Circulation. 2000 Aug 29;102(9):981-6
references.pmid: 10961961
references.citation: Int J Obes Relat Metab Disord. 2000 May;24(5):566-72
references.pmid: 10849577
references.citation: Prev Med. 2005 Jan;40(1):92-8
references.pmid: 15530585
references.citation: JAMA. 1996 Jul 17;276(3):241-6
references.pmid: 8667571
references.citation: J Cardiovasc Risk. 2001 Oct;8(5):283-90
references.pmid: 11702034
references.citation: Med Sci Sports Exerc. 2001 Jun;33(6 Suppl):S351-8
references.pmid: 11427759
references.citation: J Am Coll Nutr. 2001 Oct;20(5):494-501
references.pmid: 11601564
references.citation: Obes Res. 1998 Sep;6 Suppl 2:51S-209S
references.pmid: 9813653
references.citation: Am J Cardiol. 1990 Apr 15;65(15):1010-3
references.pmid: 2327335