title: Body mass index and daily physical activity in anorexia nervosa.
abstract: The level of daily physical activity in 11 non-hospitalized women with anorexia (age: 21-48 yr, body mass index (BMI): 12.5-18.3 kg.m-2), compared with 13 normal-weight women (age: 20-35 yr, BMI 19.2-26.7 kg.m-2), was studied in relation to BMI. Daily physical activity over a 7-d period was determined from movement registration and by combining measurements of average daily metabolic rate (measured in a respiration chamber). Group averages of daily physical activity were similar for subjects with anorexia and control subjects. However, women with anorexia had either a low or a high level of daily physical activity, whereas most control subjects had a moderate level of daily physical activity. In the women with anorexia, daily physical activity was significantly related to BMI (r = 0.84). Subjects with a BMI > or = kg.m-2 were equally or more active compared with control subjects, while subjects with a BMI < 17 kg.m-2 were equally or less active compared with control subjects. The increased physical activity at BMI > or = 17 kg.m-2 is considered to be facilitated by an improving physical capacity combined with the advantages of a low body mass during weight-bearing activities. At lower BMI, undereating and declining physical capacity may have caused the observed decrease in daily physical activity.
authors.affiliation: Division of Computational and Experimental Mechanics, Einhoven University of Technology, The Netherlands.
authors.forename: C V
authors.initials: CV
authors.lastname: Bouten
authors.forename: W D
authors.initials: WD
authors.lastname: van Marken Lichtenbelt
authors.forename: K R
authors.initials: KR
authors.lastname: Westerterp
mesh_terms: D000328:Adult; D000856:Anorexia Nervosa / Q000503:physiopathology*; D015992:Body Mass Index; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D009068:Movement / Q000502:physiology; D012890:Sleep / Q000502:physiology