-- On most summer days, New York City is such a grotesquerie of humidity and sweat it should only be approached in a moon suit with a Freon pack.

Then there is Raj Iyer, a 42-year-old who lives in Queens and works in information technology. To him, the heat is not something you beat -- the heat is something you embrace, lovingly and enthusiastically and as often as possible. This is why on a recent afternoon, with the temperature at 93 degrees and the rest of the city chugging bottled water, Iyer is wearing little more than shorts and a smile, and heading, of all places, into a sauna.

"It's about 195 degrees in there," he says giddily, gesturing toward the sweat room that is his destination. "It's nirvana."

Iyer is just one of many customers here at Spa 88, an expansive, 15,000-square-foot Russian-style operation located under a handful of shops on a busy stretch of Wall Street. Everyone in this place has spent $28 for the privilege.

Let's get the obvious question out of the way first.

Are these people insane?

"No," says Iyer, with total sincerity. "I've been coming here almost every day for four years, and in the summer, it's the best time. When I leave here, the outside will feel so cool to me I'm going to need a light sweater."

You study Iyer for the telltale signs of madness -- glassy eyes, tics, frothing at the mouth. Nothing. Soon a group of fellow sauna lovers is gathered around him, men and women, all of them in towels and bathing suits, talking over each other, insisting they are not merely sound of mind but far healthier than everyone huddled in air-conditioned rooms.

They all have theories. It closes the pores, it opens the pores, it heats the blood, it pumps the aorta, it detoxes the systems. One guy with a green tattoo on his chest talks about endorphins and claims he hasn't been sick in four years, courtesy of regular visits to Spa 88. A Brazilian woman in a bikini says the sauna helped her get over depression brought on by a car accident.

"It's magical," says Simone Lane. "I had been poisoned by pills and this cured me."

"I have the internal organs of a 19-year-old," says Iyer. "My body tells me I am going to live to be 100."

We'll see. In the meantime, Iyer has generously offered a tour of the facilities, one of the largest sauna joints in New York. There is a slightly kitsch vibe here, lots of wood paneling and vintage signs. The premises include a large swimming pool, a juice bar, a cigar room and a restaurant, where you can buy traditional Russian specialties such as Siberian pelmeny with beef stuffing and Ukrainian varenikes.

The big draw, though, are the saunas. Spa 88 has three of them, one Russian, one Turkish and one American. Iyer heads to the American sauna, which is a dry Arizona heat, times two. There are three tiers of benches -- the higher, the hotter. Iyer plops on the top tier, of course, where he says it is 195, and then leans back to relax. It's so blazing that you can't move, unless it's to take a bucket of cold water, helpfully offered by sauna-mates, and pour it over your head.

Nearby, a man is flogging a guy with a shrub. "Platza," explains Iyer. Those are oak leaves, wrapped at the stem. The guy getting beaten is paying $20 for it.

"You want to try it?" asks Iyer.

Not now. Not ever, to be honest.

"I read a lot about saunas on the Internet," says Iyer, who of course is coated in perspiration. "I found a couple Web sites that are close to scientific that say a sauna like this is as good for your body as 12 minutes on an exercise cycle. Really."

Iyer heads out the door to a small cold dunking pool. The switch from extreme heat to chilled water makes your head spin and leaves you gasping. Then back into the sauna. Then back to the dunking pool. Iyer will do this four or five times in a typical visit.

"My wife thinks I'm having an affair," he says, smiling, as he heads back out to the dunking pool. "It's an addiction."

Actually, it is like a drug. After a 45-minute stay, you leave Spa 88 and head back into the appalling New York weather, and you know something? It doesn't bother you. Nothing bothers you. Blame endorphins, your aorta, your pores -- whatever it is, you're basically stoned out of your mind.

A stray thought occurs amid the euphoria. If you can't stand the heat, getting out of the kitchen is a fine idea. But if you can't get out of the kitchen, crawling into the oven is a pretty good time.

Patrick Flanagan, right, and Anton Schegolev use the sauna at the Wall Street Bath and Spa 88 on a very hot day in Manhattan. Charles Guerrero, above, and Raj Iyer, far right, alternate between the sauna's extreme heat and the cold pool at New York's Spa 88. Simone Lane, right, also at Spa 88, claims that the sauna helped her with the psychological effects of an auto accident. "It's magical," she says.