For three minutes Tuesday Rupp let nitrogen vapor blow across his body, lowering his skin temperature to about 32 degrees. The treatment, known as a cryosauna, or cryotherapy, is designed to inhibit inflammation and enhance blood flow and oxygenation of the muscles.       

On Saturday night, Rupp had won a silver medal in the 10,000 meters, the first Olympic medal in the event for an American since 1964 and only the third ever. His training partner, Mo Farah of Britain, had won gold.