In a double-blind placebo controlled design, recreationally active subjects (n = 10; mean ± SD; age = 21.4 ± 2.4 yrs; height = 175.8 ± 78 cm; weight = 75.0 ± 10.6 kg) were randomly assigned to a mushroom (MR; n = 6) or placebo (PL; n = 5) treatment group. All subjects completed a maximal graded exercise test, 6 min sub-maximal cycle test, and 3 min all-out cycle test, each separated by at least 24 hrs. Maximal oxygen consumption (VO2 max), time to exhaustion (TTE), and ventilatory threshold (VT) were determined via respiratory gas analysis during the maximal graded exercise test performed on a cycle ergometer. Lactate and oxygen saturation (SPO2) were measured at 0, 2, 3 and 6 min during the 6 min sub-max cycle test at a workload of 60% between VT and VO2 max. Peak power output (PP) was recorded during the 3 min all-out cycle test with a resistance of 4.5% of body weight. Subjects were given capsules containing either 1.3 grams of mushroom blend or 1.3 grams of maltodextrin (PL) to be taken 3 times per day (4 grams daily) for 3 weeks. The same 3 exercise tests were repeated after 3 weeks.