Originally published on metropolis.co.jp on February 2010

Courtesy of Magma Spa

If the tips in this month’s Body & Soul article didn’t warm you up, maybe it’s time for a “Lava Bath” at Magma Spa. Not quite as deadly as it sounds, the spa’s signature treatment involves lying on a bed of polished lava rocks. At 50C (122F), the room is hot—but not sauna hot—and the stones are comfortably toasty. Bathers in cotton pajamas spend 15-20 minutes on the rocks (enough time to produce shocking amounts of sweat), followed by five minutes in the “cool down” room, repeating the cycle a number of times.

The stones are sourced from Mount Fuji, and Magma Spa says that they naturally emit “minus ions”—those supposedly beneficial molecules that come out of everything from air purifiers to fancy hair dryers. Soaking up minus ions is believed to awaken sleeping cells, rejuvenate the body, and help relieve fatigue and stiffness. The science may be fuzzy, but we can attest to feeling purged, a little spacey, and thoroughly relaxed at the end of the experience.

Magma Spa has three locations, in Daikanyama, Omotesando and Akasaka, each with stylish decor characterized by dark earth colors and gentle, warm lighting. Everything you need is included free of charge, including towels, pajamas, shampoo and hairdryers. In addition to the “Lava Bath” (¥2,600 for 60 minutes), Magma Spa also offers more conventional massage and aroma oil treatments. There are a few English-speaking staff who can help walk you through the health questionnaire and bathing process on your first visit; inquire when making a reservation.

2F Central Daikanyama, 14-23 Daikanyama-cho, Shibuya-ku. Tel: 03-5428-1860. Open daily noon-5am. Nearest stn: Daikanyama. www.magmas.jp