Living cheek by jowl with some 20 million Mexicans in the capital can give rise to inevitable tensions. What better way to cope than to submit to an Aztec sauna, a brick sweat bath called a "temescal", which has become newly trendy?

Living cheek by jowl with some 20 million Mexicans in the capital can give rise to inevitable tensions. What better way to cope than to submit to an Aztec sauna, a brick sweat bath called a "temescal", which has become newly trendy?

Although excavations of crumbled brick ruins at Chichen Itza and Piedras Negras show that the sweat lodge has been around here for more than 1,200 years and used by both the Maya and Aztec civilisations, it is difficult to find a truly old-fashioned vapour bath built of bricks these days in Mexico City. Not so in the New Age outpost called Tepotzlan, a village an hour's drive south of the city, with its own pyramid and, some residents insist, a landing strip for UFOs.

Here, resorts and private houses have revived arcane traditions and come complete with what looks like a pizza oven. Maria Laura has a temescal in her garden, and she invited me to drive down and sweat off the rigours of urban living.

To enter the temescal, one climbs in on hands and knees, as if returning to a big brick womb. Some temescals can contain up to 10 people, but most are now designed for one or two bathers. For this I am thankful. I would not have wanted a crowd to witness me whimpering on my little mat in that adobe furnace. By the time I was heating up, and ready to have my skin rubbed with herbs and corn leaves before getting flushed with cold water, I was convinced that my eyeballs would melt if I dared open the lids. My problem is an overactive imagination and a slightly claustrophobic nature.

I do not do well in dark confined places where the temperature rises to 122 degrees Fahrenheit (50C). I kept fantasising I was being baked for someone's supper. The promise of tingling skin, free from impurities, did not do anything to ease my discomfort.

A temescal is meant to heat up evil spirits and cast them out of a weakened body, and does a mean job on arthritic aches and pains as well. But it is like entering the underworld. I learnt later that even the Spanish Inquisitors, who extended their campaigns to Mexico's settlers, were alarmed by the rigours of the temescal. But then these 16th-century church elders were never prone to long soaks in the tub. In fact, one contemporary Queen of Aragon was proud of having bathed only twice in her life, once when she was born and once when she was married. Spaniards in Mexico were highly suspicious of the deities that guarded Aztec sweat baths, and they decried the public nudity and the use of black magic herbs.

One priest penned this contemptuous diary entry: "This is a picture of the baths of the Indians which they call 'temazcalli.' At the door is an Indian who was the mediator for illnesses. When a sick person took a bath he offered copal incense to his idol and stained his skin black in veneration to the god Tezcatlipoca. Many Indians, stark naked, took these baths and committed nasty and vile sins within."

Maria Laura's adobe temescal is immaculate, and measures about eight feet wide, but it gets far less light than a prison torture cell, which it resembles in dimensions. Its smooth floor is convex, obviously not meant for pacing, and at its highest point the ceiling arches up to about six feet. Opposite the entrance is a stone fireplace with a round chimney above it, and there is a porous stone that seals the vault between the fire and the bather. In the heat and dark, one lies on the mat. The scorched earth smell of the hot brick and the eucalyptus branches envelops you when water hisses on the hot rocks. There is nothing to do but sweat.