There are people who enjoy going to the gym, and then there are people, like me, who enjoy having been.

For most New Yorkers, the gym is as important a part of life as fresh air and good closet space. Often, it will provide the only opportunity to venture out of the dark, tiny space we call home to experience a more expansive and social environment, with direct sunlight and room to move around. It's like being outdoors, only better.

I have never understood why some people choose to exercise outside, though. If you live in Montana, that's one thing. But I have friends who tell me they are going for a jog along the streets of Manhattan. Is there anything less appealing? Why not just stand in the middle of the Queens Midtown Tunnel at rush hour and inhale?

This is why the gym was invented. So that people like me, who don't want the elements to interfere with the misery of exercising, can get their workout over and done with as quickly and efficiently as possible. I will leave running around the reservoir in Central Park, with frostbitten eyelashes and mud-soaked trainers, to the intrepid athletes and tourists. Where is the sense in paying $120 (Pounds 65) for trainers if they can't look stylish? They are not meant to be used and abused. They belong on a treadmill in front of a television, poking out, shiny and clean, from beneath the hem of a hot-pink terry-towelling tracksuit.

In New York, the gym you belong to is a reflection of who you are. For instance, if you desire function, you join the YMCA. If you are an insomniac crazy person and want to work out at 2am, you belong to the 24-hour Crunch gym. If you play squash or tennis, you go somewhere with courts.

There is Chelsea Piers, an activities monstrosity on the West Side Highway, with a skating rink, a swimming pool and a putting green. The people in gossip columns (such as Cindy Crawford) are always seen there, but what they don't mention is how they got there. Every time I am invited, I can't make it, literally -it requires tactical planning to figure out how to cross the highway, and I end up haggard and exhausted before even working out.

Everyone I know who belongs to Chelsea Piers owns a car and a driver, and doesn't have a job. Going to the gym is their job.

Some gyms, like nightclubs, have a door policy that hinges on status. All have memberships, but when I was invited to go with a friend to the Reebok Sports Club and couldn't get in, I was convinced it was because I was too fat.

I was assured that it was because I didn't have the proper identification. But come on: what am I going to steal, a StairMaster?

Security has become a concern everywhere in the world, but nowhere is as safe as the Equinox gym, in the West Village. It is easier to get on an El-Al flight to Jerusalem than it is to get into Equinox without the proper ID -which, of course, is why I belong. If there was ever another attack on New York, I know where I would want to be. And chances are I would be there. It has everything I need in life, and it is an all-glass structure, so, unlike my apartment, it is pleasant. It is also somewhere to go.

On a Friday night, when the rest of the city is out doing something exciting and glamorous, I can head over to Equinox and not feel like a loser, because I am surrounded by other people who, like me, have nothing better to do. It has a restaurant, internet access, a spa, hybrid classes such as yogalates and aerobox, plasma-screen televisions -and I can work out.

Later this year, Equinox is due to open in the UK. Will it be filled with its own kind, like Soho House in Manhattan -former New Yorkers sipping Vitamin water? Or will Brits welcome the opportunity to work out indoors, shielded from the hazards of rain, wind and fresh air?

From my experience, the gyms in London are more dignified -not quite as rock'n'roll and sceney -which, I have to say, I prefer. In London, people go to the gym to be left alone; in New York, it is more of a social activity.

On my last visit to my gym, 50 Cent was surrounded by a coven of ladies as he explained the origin of a particular tattoo on his biceps. Last time I was at a gym in London, I saw Ralph Fiennes elegantly pedalling a stationary bike while he read the FT. Even his sweat was refined.