A Himalayan fungus that has long been used in Traditional Chinese Medicine, Cordyceps sinensis, attracted global attention in 1993 when Chinese athletes broke world records in track and field. To study its effects, Brazilian researchers conducted a randomized, double-blind, placebo-controlled study in which they gave 30 amateur marathoners two grams of the fungus each day for 12 weeks. Compared to the placebo group, those in the Cordyceps group had significantly lower heart rates at eight weeks and improved aerobic performance at 12 weeks.