This is a randomized, placebo-controlled, double-blind blind, repeated measures (cross-over) study. Approximately 12 healthy adult men will consume, in a random order, a placebo prior to exercise in normoxia, a placebo prior to exercise in hypoxia, 1000 mg of Aes-103 prior to exercise in hypoxia, and 3000 mg of Aes-103 prior to exercise in hypoxia.