The integration of the physical and the spiritual is at the heart of the tradition of sweat lodges, a Native American ceremony believed to be the most widely practiced indigenous healing ritual. "For us, it's sort of like going to church, something to practice on a regular basis," says Mehl-Madrona, research
coordinator for the program of integrative medicine at the University of Arizona in Tucson. A sweat can be used as its own ceremony, to cleanse oneself and reconnect with Mother Earth, or as preparation for other important undertakings, such as the Vision Quest or the Sun Dance.

The sweat lodge is a place of magic and visions, but it is also physically taxing. Drink plenty of water on the day of a swat. Eat lightly, wear loose, lightweight clothing.

The particulars of the rituals vary from tribe to tribe and from family to family, says Mehl-Madrona. Yet the central concept is always to purify body, mind and soul through intense heat generated by pouring water over hot rocks. Some form of this ancient practice is found in cultures around the world, from the Finnish sauna to the Russian bania, and from the Jewish shvitz to the Turkish hamman.

"You're essentially generating a fever in the body," Mehl-Madrona explains. The physical benefits of this have been enumerated in study after study, he says. A body temperature of 102 to 106 degrees ("which is what we suspect is generated in a sweat lodge") creates a hostile environment for bacterial and viral infection. Sweating flushes toxic metals, such as copper, lead and mercury, and removes excess salt, a benefit for those with mild hypertension. The heat and sweating also helps ease soreness and stiffness, and dilates capillaries, increasing blood flow to the skin. Mehl-Madrona participates in sweat-lodge ceremonies with Native American patients and others who feel they might benefit, but the physical rewards are only one small reason. A sweat lodge can't be separated from its context as a spiritual ritual or it loses its power. "If you just want to feel better sweating, go take a sauna, but don't call it a sweat," he insists. "Healing comes on a spiritual level. We have to make ourselves available to the spiritual realm. Ceremony and ritual provide the means of making ourselves available." ceremony and song Almost every aspect of a sweat lodge has a symbolic meaning, says Edward Albert, the California state commissioner for Native American lands. Lodges are usually round or oval, reflecting the shape of the womb, and the experience is likened to being reborn in healing energy. The flap or door of a lodge is generally built very low, forcing people to enter crouched or even on their knees as a show of humility and respect for the earth as a sacred, living entity. Although construction varies, numerous tribes prefer willow, which has long been used medicinally (its bark contains salicin, the analgesic in aspirin compounds); it's known as the "tree of love" in the Seneca tradition, due to its resilience and grace. Since willow dies in the winter and comes up again in spring, it also offers a lesson in death and rebirth. Saplings are set up to represent four quadrants, signifying the four elements and the four directions. Originally, lodges were covered with animal skins; contemporary structures use blankets or tarpaulins. A fire pit just outside the lodge is used to heat rocks, called the Stone People, which represent one's elders. When the rocks are thoroughly heated, they are brought into the tent in a series of four rounds (or sometimes 16 or 32 rounds). Then water is poured on the stones, generating steam, which symbolizes, in part, the release of ancient knowledge.

A sweat begins in total silence-sometimes thought of as the "true voice of the Creator"-but songs, prayers, chants and heartfelt talk are central to most ceremonies. Sweats can last for days at a time in traditional settings, but for the newly initiated a two-hour series of rounds provides a complete experience.

Though generally considered safe, says Mehl-Madrona, the excessive sweating produced in a lodge isn't for every­one, because it can adversely interact with medication or exacerbate certain conditions. Pregnant women, people with heart disease, and anyone taking benzodiazepines (Xanax, Valium) should check with their physicians before participating in a sweat lodge ceremony.

Others who should proceed with caution are very overweight and very underweight people, who have an equally difficult time regulating body temperature and are more likely to faint in excessive heat. And those who suffer from claustrophobia and post-traumatic stress disorders can have their conditions triggered by the dark, closed space of a lodge.