Muscle creatine loading in man.
Hultman, E., K. Soderlund, J. A. Timmons, G. Cederblad, and P. L.
Greenhaff.
Department of Physiology and Pharmacology, University Medical
School, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom,
Department of Clinical Chemistry, Huddinge University Hospital and
Department of Physiology III, Karolinska Institute, S-14186 Huddinge,
Sweden
APStracts 3:0104A, 1996.
The effect of dietary creatine supplementation on skeletal muscle
creatine accumulation and subsequent degradation and on urinary
creatinine excretion was investigated in 31 male subjects who
ingested creatine in different quantities over varying time periods.
Muscle total creatine concentration increased by 20% following 6 days
of Cr supplementation at a rate of 20 g/day. This elevated
concentration was maintained when supplementation was continued at a
rate of 2 g/day for a further 30 days. In the absence of 2 g/day
supplementation, total creatine concentration gradually declined,
such that 30 days following the cessation of supplementation the
concentration was no different from the pre-supplementation value.
During this period, urinary creatinine excretion was correspondingly
increased. A similar, but more gradual, 20% increase in muscle total
creatine concentration was observed over a period of 28 days when
supplementation was undertaken at a rate of 3 g/day. In conclusion, a
rapid way to "creatine load" human skeletal muscle is to
ingest 20 g of creatine for 6 days. This elevated tissue
concentration can then be maintained by ingesting 2 g/day thereafter.
The ingestion of 3 g of creatine/day is in the long term likely to be
as effective at raising tissue levels as this higher dose.
Received 15 August 1995; accepted in final form 1 February 1996.
APS Manuscript Number A899-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 24 February 96