Although sports nutrition drinks are stepping out beyond the world of athletes, fitness enthusiastic still rely on them for hydration, increased endurance, muscle recovery and more. Sustamine, a dipeptide combining two amino acids, L-glutamine and L-alanine, already has some research backing its ability to improve post-exercise recovery via protecting muscles from post-workout protein degradation. Now a new study paired the ingredient with a commercially available sports drink to examine time to exhaustion and physiological measures during prolonged endurance exercise (J Am Colle Nutr. June 22, 2015).

A total of 12 endurance-trained men performed four trials, each consisting of a one-hour treadmill run at 75-percent VO2peak (VO2peak is the highest volume of oxygen used during an exercise, while the maximum attainable oxygen volume is called VO2max) followed by a run to exhaustion at 90-percent VO2peak. One trial consisted of no hydration, another required drinking only a sports drink and two trials required ingestion of a low dose (300 mg) and high dose Sustamine (1 g) added to the sports drink. During the fluid ingestion trials, 250 mL was consumed every 15 minutes.

Time to exhaustion was significantly longer during the low- and high-dose trials compared with no hydration. No differences were noted in time to exhaustion between the drinking only a sports drink and no hydtration. Plasma glutamine concentrations were significantly elevated at 45 minutes in low- and high-dose trials and remained elevated at 60 minutes during high-dose. Sodium concentrations increased from the beginning of exercise and remained stable for the duration of the one-hour run. At 60 minutes, plasma sodium was significantly lower in all trials compared to no hydration.

These results indicated that ingestion of Sustamine at either the low or high dose significantly improved time to exhaustion during high-intensity exercise compared to a no-hydration trial.