For some, the challenge, and therefore the pleasure, of a sport increases as its risk increases. Enthusiasts may try to reduce the risk by preparing adequately, but will not tolerate eliminating its exciting mental and physical challenges.
Surfing, mountaineering, skiing, parachuting, and bungee-jumping are among the sports which have an inherently high level of risk of physical danger. But many other sports present less acknowledged or even hidden dangers. Anglers, canoeists and recreational users of freshwater are at risk from polluted water. Hepatitis is not infrequently caught by surfers and others in the sea near sewage outfalls. Joggers in Mexico City are three times more likely to have bronchial problems as sedentary people because of the excessive inhalation of polluted air.
Trouble occurs not from extreme sports in themselves but when you are unaware of the risks that are undertaken. The risk is acceptable when it is known.