title: Patterns and energy expenditure of free-living physical activity in adolescents with sickle cell anemia.
abstract: OBJECTIVE
  Our purpose was to examine the relationship between physical activity (PA), PA-associated energy expenditure (PAEE), and total daily energy expenditure (TEE) in free-living adolescents with sickle-cell anemia (SCA).
  
  
  METHODS
  Adolescents with SCA (n = 28) were matched for sex and age with 22 healthy control participants. PA was measured for 6 to 8 consecutive days with a triaxial accelerometer and resting energy expenditure (REE) by whole-room indirect calorimetry. TEE was calculated by summing PAEE and REE.
  
  
  RESULTS
  TEE was similar, REE was higher (difference, 209 kcal x day(-1); P =.0001), and PAEE was lower (difference, 657 kcal x day(-1); P <.001) in patients with SCA than in control participants. In SCA, there was a positive linear relationship between PAEE and hemoglobin concentration (r (2) = 0.583). Time spent in PA of moderate and high intensity was lower in patients with SCA than in control participants (18 +/- 22 vs 48 +/- 31 min/d; P <.0001).
  
  
  CONCLUSIONS
  In adolescents with SCA under free-living conditions, there is a significant intra and interindividual variability in the amount of PA, PAEE, and PA patterns. Because of a lower PAEE and a higher REE, TEE is similar in adolescents with SCA and healthy adolescents. An association of PAEE with hemoglobin concentration may be a part of an energy saving compensatory mechanism in SCA.
authors.affiliation: Center for Nutrition and Department of Family and Community Medicine, Meharry Medical College, Nashville, Tennessee 37208, USA.
authors.forename: Maciej S
authors.initials: MS
authors.lastname: Buchowski
authors.forename: Karen M
authors.initials: KM
authors.lastname: Townsend
authors.forename: Ruth
authors.initials: R
authors.lastname: Williams
authors.forename: Kong Y
authors.initials: KY
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000503:physiopathology*; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male