title: Moderate exercise and bright light treatment in overweight and obese individuals.
abstract: OBJECTIVE
  Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals.
  
  
  METHODS
  Twenty-five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep.
  
  
  RESULTS
  Body weight decreased significantly with exercise in subjects in the light and non-light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep.
  
  
  CONCLUSIONS
  This preliminary study is the first to show that addition of bright light treatment to a 6-week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.
authors.affiliation: Sleep Research Unit, Department of Psychiatry, Toronto Western Hospital, University Health Network, University of Toronto, Ontario, Canada M5T 2S8.
authors.forename: Andrea
authors.initials: A
authors.lastname: Dunai
authors.forename: Marta
authors.initials: M
authors.lastname: Novak
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Chung
authors.forename: Leonid
authors.initials: L
authors.lastname: Kayumov
authors.forename: Andras
authors.initials: A
authors.lastname: Keszei
authors.forename: Robert
authors.initials: R
authors.lastname: Levitan
authors.forename: Colin M
authors.initials: CM
authors.lastname: Shapiro
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000339:Affect; D000416:Alberta; D015992:Body Mass Index; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000517:prevention & control / Q000628:therapy*; D050177:Overweight / Q000502:physiology*; D018579:Patient Selection; D010789:Phototherapy; D012890:Sleep; D013997:Time Factors