title: Prescribing exercise in multiple short bouts versus one continuous bout: effects on adherence, cardiorespiratory fitness, and weight loss in overweight women.
abstract: OBJECTIVE
  To investigate whether prescribing exercise in several short-bouts versus one long-bout per day would enhance exercise adherence, cardiorespiratory fitness, and weight loss in overweight adult females in a behavioral weight control program.
  
  
  METHODS
  Randomized controlled trial with subjects randomized to either a short-bout exercise group (SB, n = 28, age = 40.4 +/- 5.9 yrs) or a long-bout exercise group (LB, n = 28, age = 40.9 +/- 7.3 yrs), with subjects followed for a period of 20 weeks. Both groups were instructed to exercise 5 days per week with exercise duration progressing from 20 to 40 min per day. The LB group performed one exercise bout per day, whereas the SB group performed multiple 10 min bouts of exercise per day. The recommended caloric intake for all subjects was 5022-6277 kJ/day (1200-1500 kcal/day), with fat reduced to 20% of caloric intake.
  
  
  METHODS
  Fifty-six obese, sedentary females (BMI = 33.9 +/- 4.1 kg/m2).
  
  
  METHODS
  Exercise participation was assessed from self-reported diaries and Tri-Trac Accelerometers. Cardiorespiratory fitness was assessed using a submaximal cycle ergometer test.
  
  
  RESULTS
  Exercising in multiple short-bouts per day improved adherence to exercise: the SB group reported exercising on a greater number of days (mean +/- s.d. = 87.3 +/- 29.5 days vs 69.1 +/- 28.9 days; P < 0.05) and for a greater total duration (223.8 +/- 69.5 min/week vs 188.2 +/- 58.4 min/week; P = 0.08) than the LB group. Predicted VO2Peak increased by 5.6% and 5.0% for the LB and SB groups, respectively (P < 0.05). There was a trend for the weight loss to be greater in the SB group (-8.9 +/- 5.3 kg) compared to the LB group (-6.4 +/- 4.5 kg; P < 0.07).
  
  
  CONCLUSIONS
  These results suggest that short-bouts of exercise may enhance exercise adherence. Short-bouts of exercise may also enhance weight loss and produce similar changes in cardiorespiratory fitness when compared to long-bouts of exercise. Thus, short-bouts of exercise may be preferred when prescribing exercise to obese adults.
authors.affiliation: Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Jakicic
authors.forename: R R
authors.initials: RR
authors.lastname: Wing
authors.forename: B A
authors.initials: BA
authors.lastname: Butler
authors.forename: R J
authors.initials: RJ
authors.lastname: Robertson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D004435:Eating / Q000502:physiology; D005081:Exercise Therapy / Q000592:standards*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D010349:Patient Compliance; D012727:Sex Characteristics; D013997:Time Factors; D015431:Weight Loss / Q000502:physiology*