Anecdotal reports can be found in the literature of athletes who suffer from an injury, yet continue to participate in their sport with little or no pain. These reports have resulted in an interest in the possible role of stress, including exercise, in analgesia. Exercise-induced hypoalgesia (EIH), a decrease in pain perception following exercise, has been found to occur in healthy adults. In the 1970’s opioid peptides with analgesic properties were discovered (Dalayeun, Nores & Bergal, 1993). One of these peptides, β-endorphin, is believed to be released from the anterior pituitary into the circulation under a variety of stressors, including exercise. Investigations into the plasma β-endorphin response with exercise have confirmed an exercise related increase. While animal studies may bring additional perspective to the study of EIH, this review will focus on human studies only. The intent then of this literature review is to answer the question: Does plasma β-endorphin concentration influence the EIH response in healthy adults?