Robert Bosch, Extreme Photographer

A feature of such activities in the view of some is their alleged capacity to induce an adrenaline rush in participants. However, the medical view is that the rush or high associated with the activity is not due to adrenaline being released as a response to fear, but due to increased levels of dopamine, endorphins and serotonin because of the high level of physical exertion. Furthermore, a recent study suggests that the link to adrenaline and 'true' extreme sports is tentative. The study defined 'true' extreme sports as a leisure or recreation activity where the most likely outcome of a mismanaged accident or mistake was death. This definition was designed to separate the marketing hype from the activity. Another characteristic of activities so labeled is they tend to be individual rather than team sports. Extreme sports can include both competitive and non-competitive activities.
• Motivation
Eric Brymer also found that the potential of various extraordinary human experiences, many of which parallel those found in activities such as meditation, was an important part of the extreme sport experience.
Some of the sports have existed for decades and their proponents span generations, some going on to become well known personalities. Rock climbing and ice climbing have spawned publicly recognizable names such as Edmund Hillary, Chris Bonington, Wolfgang Gullich and more recently Joe Simpson. Another example is surfing, invented centuries ago by the inhabitants of Hawaii.