The effect of dietary creatine supplementation on skeletal muscle metabolism in congestive heart failure.
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.
Andrews
R
R
Department of Cardiovascular Medicine, University Hospital, Nottingham, U.K.
Greenhaff
P
P
Curtis
S
S
Perry
A
A
Cowley
A J
AJ
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
D002316:Cardiotonic Agents; D019344:Lactic Acid; D000641:Ammonia; D003401:Creatine