Altered states of consciousness have often been reported by adventure athletes such as rock climbers, trail runners, big-wave surfers, ski mountaineers, etc. Their challenges vary, but all show similar patterns of psychic response: their consciousness gets altered. We struggle to label those altered states with names like runner’s high, peak experience, or summit euphoria. And we take a stab at explaining them as adrenaline junkies or with beta-endorphin. Both of those popular ideas turn out to be wrong. What is it then? We noticed that their altered states all share many characteristics with the effects of psychedelic drugs. The challenging nature of their pursuits all share the qualities of seeking physiological stress under conditions of controlled fear. Anandamide is demonstrated to rise sharply in endurance athletes which makes a convincing case for a psychedelic explanation for the altered states experienced by adventure athletes