title: Sitting comfortably versus lying down: is there really a difference in energy expenditure?
abstract: OBJECTIVE
  Energy expenditure (EE) during sitting is widely assumed to be higher than that while lying down, but supporting evidence is equivocal. Despite this, resting EE in the sitting position is often used as a proxy for basal metabolic rate. Here we investigate whether EE differs in the comfortable seated position compared to supine (lying) position.
  
  
  METHODS
  EE and respiratory quotient (RQ) were measured (by ventilated hood indirect calorimetry) in 19 healthy subjects (9 men, 10 women) after an overnight fast. Supine measurements were made using a comfortable clinical tilting table and sitting measurements made using an adjustable, ergonomic car seat adapted for the hood system. After about 30 min of rest in either position, metabolic monitoring was conducted until stabilization of EE for at least 15 min in each posture.
  
  
  RESULTS
  EE in the sitting position was not significantly different compared to supine (<2% difference). By contrast, heart rate was higher by 7 beats/min (p < 0.05). RQ was slightly but significantly decreased during sitting compared to lying (p < 0.05), with no change in breathing rate.
  
  
  CONCLUSIONS
  This study suggests that the ventilated hood calorimetry system for assessment of REE after an overnight fast in a comfortable sitting position can be used as a good proxy of the basal metabolic rate. It also underscores the applicability of the ventilated hood system to measurements of resting EE in the sitting posture which, compared to supine posture, may be more acceptable/convenient to the subject/patient participating in postprandial metabolic studies lasting several hours.
authors.affiliation: Department of Medicine/Physiology, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland. Electronic address: jenniferlynn.miles@unifr.ch.
authors.forename: J L
authors.initials: JL
authors.lastname: Miles-Chan
authors.affiliation: Department of Medicine/Physiology, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Sarafian
authors.affiliation: Department of Medicine/Physiology, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
authors.forename: J P
authors.initials: JP
authors.lastname: Montani
authors.affiliation: Department of Medicine/Physiology, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
authors.forename: Y
authors.initials: Y
authors.lastname: Schutz
authors.affiliation: Department of Medicine/Physiology, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland. Electronic address: abdul.dulloo@unifr.ch.
authors.forename: A G
authors.initials: AG
authors.lastname: Dulloo
mesh_terms: D000328:Adult; D001481:Basal Metabolism / Q000502:physiology; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D004734:Energy Metabolism / Q000502:physiology*; D005215:Fasting; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D055815:Young Adult
keywords: BMR; BR; EE; Energy cost; Energy expenditure; HR; Posture; REE; RQ; Respiratory quotient; Sedentary behavior; Sitting; basal metabolic rate; breathing rate; energy expenditure; heart rate; respiratory quotient; resting energy expenditure