Extreme adventure challenges can help office workers deal with the "anxieties of modern life" new research suggests.
Cardiff University academics looked into the reasons why people participate in the Tough Mudder event.
The experience is "deliberately marketed" as painful, with obstacles including wires delivering 10,000 volt electric shocks.
Injuries have included strokes, heart attacks, and even death - but 2.5m people have entered.
Researchers discovered that pain helps individuals deal with the physical inactivity of office life, and allows participants to "rediscover the nature of their body."Image copyright Getty Images Image caption A competitor in a Henley-on-Thames Tough Mudder event in 2014
Dr Rebecca Scott, of Cardiff Business School, said: "On the one hand, consumers spend billions of dollars every year on pain relief, while exhausting and painful experiences such as obstacle races and ultra-marathons are gaining in popularity."
The research, a joint project between Cardiff, Singapore's Nanyang Business School, and Kedge Business School, France, also found pain "facilitates escape" and provides a "temporary relief from the burdens of self-awareness."
Professor Bernard Cova, of Kedge Business School, added: "Electric shocks and ice-cold water may be painful but they also allow participants to escape from the demands and anxieties of modern life.
"By leaving marks and wounds, painful experiences help us create the story of a fulfilled life spent exploring the limits of the body."