Yesterday, the hottest day so far this year, they were out in force. A kind of shirtless Army of the Potomac, coming singly, in pairs and threes - moving across the 14th Street Bridge, around the Tidal Basin and along the Mall.

People who couldn't be inside were sitting under trees as though they had decided to make a career of it. But the lunch-hour joggers were out, wearing their traditional uniform - shorts, sweat socks, shoes (Adidas, Nike, Brooks, New Balance, Sears and Etonic) and no shirts.

Why, you may be asking would anyone want to be out running at 1:15 p.m., when the temperature was above 90? Well, why not? If you can run when its's 10 degrees, you can run when it's 90," Tim Dudley, a stockbroker, said during a break along the Ellipse.

"If you'll stop for this," one of his running partners, Jim walker, said, "you'll stop for anything."

That, at least, explains why someone didn't let a day when the temperature reached 97 at 3:10 p.m. (the record is 98) stop him from running. What isn't explained is why anyone would want to go out in the first place.

"It's mentally relaxing." Walker said. "The market's crummy, so it takes your mind off it."

And don't discount guilt as a motivating factor, either. "You get to the point where you feel bad about yourself if you don't do it," Dudley said.

"We come back to the office," the third member of the trio, Brian Garrity, said, "most of the people look like they've been sleeping."

Walker, Dudley, Garrity and the legions of other runners out yesterday and every day, on the other hand, look as though they've run through a car wash - faces flushed and dripping with sweat (except for Garrity, 24, who looked like he just walked out of an ad for an antiperspirant.)

There are dozens of stories about joggers in Washington - like the one about the administration official who hates his job. He spends his morning looking forward to running at lunchtime and his afternoon thinking about how much he enjoyed running.

Washington has all kinds of joggers - jogging stockbrokers and jogging military men, jogging Cabinet secretaries and jogging housewives, jogging bureaucrats and jogging journalists. What they all get from jogging, aside from sore knees, shin splints and an occasional twisted ankle, is a sense of participation in the greatest mass movement since Walter O'Malley moved the Brooklyn Dodgers to Los Angeles.

For what? Because, Garrity said, in an explanation reminiscent of hitting yourself over the head with a hammer, "you feel so good when you get done."