During intense exercise, the body produces hydrogen ions that increase the acidity of working muscles. This
increase in acidity results in that burning sensation you feel when you do an intense bout of exercise like a set of high
repetition squats. Increased acidity also results in fatigue as you already know when that feeling comes along, fatigue
is right around the corner. Muscles have their own protective mechanisms to cope with the increase in acidity through
biochemical buffers. Thus, one theoretical way to combat fatigue and enhance performance is to enhance the muscle's
buffering capacity. However, few supplements have ever been shown to have an affect on muscle buffering. Some very
exciting work done in thoroughbred horses (athletes of the animal kingdom) shows great promise for the dietary supplement
Beta-Alanine and
L-histidine. These two
amino acid supplements are the precursor for carnosine.
Carnosine is a very
important buffer inside the muscle. This study supplemented thoroughbred horses with beta-alanine and L-histidine 3x/day
for 30 days and measured muscle carnosine in different fiber types. Carnosine levels increased 27% in fast type IIA and
13% in fast type IIB muscle fibers. The increase in muscle carnosine was positively related to the plasma beta-alanine
levels. Thus, supplementation with beta-alanine and L-histidine significantly increase muscle carnosine, which leads to
increased buffering capacity. This combination supplement would be predicted to significantly
enhance high-intensity
exercise like weightlifting by allowing a couple additional repetitions to be performed as a result of delayed fatigue
from enhanced maintenance of muscle pH levels.
Dunnett M, Harris RC. Influence of oral beta-alanine and L-histidine supplementation on the carnosine content of the gluteus medius. Equine Vet J Suppl. 1999 Jul;30:499-504.
