Athletes call it the magic box: Inside it their aches and pains disappear. Practitioners of sports medicine call it the hyperbaric oxygen chamber, and because of its apparent medical benefits they, too, are among its fans.
The pressurized chamber, in which patients breathe pure oxygen, helps accelerate the rate at which soft tissue heals. With hyperbaric treatment, a sprained ankle might recover in four days instead of eight; a bruised thigh could mend in one week, not three. That's why five major professional teams in the U.S. and Canada—including the Dallas Cowboys, the San Francisco 49ers and the Vancouver Canucks—have installed chambers in their training rooms.
"It can be of dramatic assistance in healing particular types of injuries," says Jeff Ryan, director of rehabilitation in sports medicine at Temple University, where a study of hyperbaric effectiveness is underway. "It gets athletes back on the field much faster. Will it heal injuries that otherwise wouldn't heal? No. Can it help relieve fatigue or give athletes an energy boost? We can't say that."
Normally, soft-tissue injuries are healed by oxygen carried in the body's red blood cells. These cells are permanently saturated at 21% oxygen. The chamber enables the blood's plasma, the fluid surrounding the cells, to absorb more oxygen according to Henry's Law, the physical principle by which liquid absorbs a greater amount of gas in a high-pressure atmosphere. While a patient is in the chamber (usually about 90 minutes) the pure oxygen is taken into the bloodstream and delivered to injured areas.
Hyperbaric treatment is a cool way to pass the time. The one-person chamber used by sports teams resembles a cockpit. The patient sits in a soft chair, wearing an oxygen mask and looking through an oval window. Besides making comments such as, "I'm going for missile lock—two MIGs dead ahead," users of the chamber have been known to watch Star Trek through the window, listen to piped-in Pink Floyd and read Stephen King.
Hyperbaric chambers have been used to treat scuba divers suffering from the bends and to aid burn and smoke-inhalation victims. Pressurized operating rooms have been used for open-heart surgery. But it wasn't until 1989, in a study conducted in Scotland by the University of Dundee with the Dundee United soccer team, that hyperbaric treatment made a major stride into conventional sports medicine.
Based on Dundee United's success in reducing injured players' recovery time, several other soccer teams in Great Britain decided to apply hyperbaric treatment. And in the summer of 1993 their enthusiastic reports came to the attention of the Canucks' trainer, Larry Ashley. Last year, the Canucks were the first North American team to use the chamber routinely in treating injuries. "It was one fast recovery after another," says Ross Davidson, the Canucks' team doctor. "The Martin Gelinas case made me a believer. He smashed into the glass and had a terrible contusion to his quadriceps. When he came off the ice, there was already an inch of swelling. I thought he'd be out for months. Well, he went into the chamber that night, and after 12 days of twice-a-day treatment, he was back on the ice."
So far, hyperbaric medicine has drawn few complaints and revealed no side effects. When administered to divers with extreme decompression sickness, at "three-bar" pressure (the equivalent to being 66 feet below sea level), the treatment, if improperly monitored, can cause oxygen toxicity and even brain seizures. Routine sports-medicine cases, however, require two-bar pressure (33 feet below).
"At two-bar the risks are virtually nonexistent," says Dr. Fred Bove, professor of medicine and chief of cardiology at the Temple School of Medicine. "It shouldn't be used with highly claustrophobic people or with those who have sinus or inner-ear problems—the same people who shouldn't be in an airplane."
Otherwise, problems with the chamber are purely logistical. As Cowboy trainer Kevin O'Neill points out, "There can be scheduling problems. Not everyone gets in when they want to."