title: Nutritional enhancement of exercise performance in chronic obstructive pulmonary disease: a randomised controlled trial.
abstract: BACKGROUND
  Pulmonary rehabilitation is effective in improving exercise performance and health status in chronic obstructive pulmonary disease (COPD). However, the role of nutritional support in the enhancement of the benefits of exercise training has not been explored. A double blind, randomised, controlled trial of carbohydrate supplementation was undertaken in patients attending outpatient pulmonary rehabilitation.
  
  
  METHODS
  85 patients with COPD were randomised to receive a 570 kcal carbohydrate rich supplement or a non-nutritive placebo daily for the duration of a 7 week outpatient pulmonary rehabilitation programme. Primary outcome measures were peak and submaximal exercise performance using the shuttle walk tests. Changes in health status, body composition, muscle strength, and dietary macronutrient intake were also measured.
  
  
  RESULTS
  Patients in both the supplement and placebo groups increased shuttle walking performance and health status significantly. There was no statistically significant difference between treatment groups in these outcomes. Patients receiving placebo lost weight whereas supplemented patients gained weight. In well nourished patients (BMI >19 kg/m(2)) improvement in incremental shuttle performance was significantly greater in the supplemented group (mean difference between groups: 27 (95% CI 1 to 53) m, p<0.05). Increases in incremental shuttle performance correlated with increases in total carbohydrate intake.
  
  
  CONCLUSIONS
  When universally prescribed, carbohydrate supplementation does not enhance the rehabilitation of patients with COPD. This study suggests that exercise training results in negative energy balance that can be overcome by supplementation and that, in selected patients, this may improve the outcome of training. The finding of benefit in well nourished patients may suggest a role for nutritional supplementation beyond the treatment of weight loss in COPD.
authors.affiliation: Institute for Lung Health, Department of Respiratory Medicine, Glenfield Hospital, Leicester LE3 9QP, UK. michael.steiner@uhl-tr.nhs.uk
authors.forename: M C
authors.initials: MC
authors.lastname: Steiner
authors.forename: R L
authors.initials: RL
authors.lastname: Barton
authors.forename: S J
authors.initials: SJ
authors.lastname: Singh
authors.forename: M D L
authors.initials: MD
authors.lastname: Morgan
mesh_terms: D000368:Aged; D000553:Ambulatory Care; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D002149:Energy Intake; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy; D017079:Exercise Tolerance; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism / Q000534:rehabilitation*
chemical_list: D004040:Dietary Carbohydrates