Acute Effects of Branched-chain Amino Acids on Muscle pH During Exercise

概要

論文の詳細を見る
The ingestion of branched-chain amino acids (BCAAs) can be linked to lactate metabolism during heavy exercise. We investigated the effects of BCAA supplementation on muscle pH during repeated bouts of short-term exercise using ^<31>phosphorus-magnetic resonance spectroscopy (^<31>P-MRS). Fourteen healthy participants (aged 29.2±8.3 years) were assigned to either a group that received BCAA supplementation (BCAA group, n=8) or a control group (n=6). All participants performed two consecutive, 3-min repetitive handgrip exercises separated by a 1-h interval, using the non-dominant forearm. At 10min after the first bout of exercise, participants in the BCAA group consumed 8.0g of powdered BCAAs with a little water. Muscle pH (pHi) and phosphocreatine (PCr) were measured using ^<31>P-MRS during 1.5min of rest, 3min of exercise and 4min of recovery. The pHi was significantly decreased at the completion of the second, compared with the first bout of exercise in the control, but not in the BCAA group. Acidic changes in pHi were attenuated in four of the eight participants in the BCAA group at the completion of the second bout of exercise. The findings suggest that BCAAs help to prevent the metabolic acidosis of exercising muscle, probably due to a decrease in lactate production.