title: The effect of dietary creatine supplementation on skeletal muscle metabolism in congestive heart failure.
abstract: OBJECTIVE
  To assess the effects of dietary creatine supplementation on skeletal muscle metabolism and endurance in patients with chronic heart failure.
  
  
  METHODS
  A forearm model of muscle metabolism was used, with a cannula inserted retrogradely into an antecubital vein of the dominant forearm. Maximum voluntary contraction was measured using handgrip dynanometry. Subjects performed handgrip exercise, 5 s contraction followed by 5 s rest for 5 min at 25%, 50%, and 75% of maximum voluntary contraction or until exhaustion. Blood was taken at rest and 0 and 2 min after exercise for measurement of lactate and ammonia. After 30 min the procedure was repeated with fixed workloads of 7 kg, 14 kg and 21 kg. Patients were assigned to creatine 20 g daily or matching placebo for 5 days and returned after 6 days for repeat study.
  
  
  RESULTS
  Contractions (median (25th, 75th interquartiles)) until exhaustion at 75% of maximum voluntary contraction increased after creatine treatment (8 (6, 14) vs 14 (8, 17), P = 0.025) with no significant placebo effect. Ammonia per contraction at 75% maximum voluntary contraction (11.6 mumol/l/contraction (8.3, 15.7) vs 8.9 mumol/l/contraction (5.9, 10.8), P = 0.037) and lactate per contraction at 75% maximum voluntary contraction (0.32 mmol/l/contraction (0.28, 0.61) vs 0.27 mmol/l/contraction (0.19, 0.49), P = 0.07) fell after creatine but not after placebo.
  
  
  CONCLUSIONS
  Creatine supplementation in chronic heart failure augments skeletal muscle endurance and attenuates the abnormal skeletal muscle metabolic response to exercise.
authors.affiliation: Department of Cardiovascular Medicine, University Hospital, Nottingham, U.K.
authors.forename: R
authors.initials: R
authors.lastname: Andrews
authors.forename: P
authors.initials: P
authors.lastname: Greenhaff
authors.forename: S
authors.initials: S
authors.lastname: Curtis
authors.forename: A
authors.initials: A
authors.lastname: Perry
authors.forename: A J
authors.initials: AJ
authors.lastname: Cowley
mesh_terms: D000368:Aged; D000641:Ammonia / Q000032:analysis; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D003401:Creatine / Q000008:administration & dosage*; D019587:Dietary Supplements; D005080:Exercise Test; D017079:Exercise Tolerance; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D019344:Lactic Acid / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000187:drug effects; D018709:Statistics, Nonparametric
chemical_list: D002316:Cardiotonic Agents; D019344:Lactic Acid; D000641:Ammonia; D003401:Creatine