As soon as I accepted the assignment I realized I had a problem. My task was to test Tokyo's latest fad, the oxygen capsule. The trouble is I'm claustrophobic. Elevators make me tense. When watching reruns of "Star Trek," I have to avert my eyes when anyone gets sealed into a stasis chamber. There was no way I'd be able to get into a capsule barely bigger than myself.

In the last year or so health and beauty salons around Tokyo have introduced a treatment called "hyperbaric oxygenation." The brochures make big promises: "Lose 10 kilos! Relax! Have more beautiful skin!" The whole idea of supplemental oxygen struck me as just another modern excess like bottled water. But I was curious if there was anything behind the hype.

In case you slept through high school physics like I did, "hyperbaric" means a gas pressure of greater than one atmosphere, the standard pressure of the Earth's atmosphere at sea level. In hyperbaric oxygenation, a person is put into a chamber and oxygen-rich air is pumped in under pressure to force more oxygen into the blood stream. It's actually nothing new but has only just made it out of hospitals and elite sports-training facilities and into the beauty business.