They are running late for lunch. Or perhaps they are running a little early, skipping out of their Pentagon offices and Rosslyn high-rises at, say, 10:30, taking a quick spin over the bridge to the Lincoln Memorial or a long lope down to National Airport and back.

"If you can fill the unforgiving minute," wrote Rudyard Kipling, "with 60 seconds' worth of distance run . . . . "

They are taking the poem to heart.

On the roads and trails that twine between the business places of Northern Virginia, they are filling the unforgiving lunchtime with 60 minutes' worth of distance run. Maybe just 30 on a bad day. And quite possibly instead of lunch.

"I've been a lunchtime runner for 20 years," said Pat Neary, 42, an Army operations research analyst who works at the Pentagon.

All day long Neary does strength mathematical analysis for the Army, calculating how big the Army will need to be in 1997 or 2010.

"The kind of work I'm doing is very high-pressure work, very precise, very mathematical. Running allows me to step away from it and see a new way of looking at it."

Neary usually runs out of the Pentagon, down the Mount Vernon Bike Trail to National Airport and back. The seven-mile run takes 50 minutes.

"It gets you out of the office," he said. "Sitting in front of a tube for a couple hours, your eyes get tired, you get tired all over." So tired, sometimes, the line between man and machine begins to blur.

"You get into a do-loop" -- mathematical lingo for a sequence that keeps repeating itself -- Neary said. Running breaks the do-loop. "I find I'm able to rethink the problem."

Lunchtime running may be an escape from the insistent logic of the work day, but it has logistical problems of its own -- the clothing, the showers, the damp hair making spots on the suit coat, the question of lunch: to eat or not to eat.

In Northern Virginia, where hundreds of noontime runners circle the Pentagon or pound across Memorial Bridge each day, some offices have installed lockers and showers to ease the rush.

Employes at the Pentagon and Arlington Hall Station use athletic facilities there. A steady trail of lunch-runners reports daily to Arlington's Thomas Jefferson Community Center, running togs in bright bags slung over their shoulders.

"Arlington Hall Station has its own gym and locker room equipment. Most of the places I have lived and worked have had something like that," said Fred Bryant, a lawyer for the Military District of Washington. "I've been in a position myself where I have left clothes in the office; one place I worked had showers and we would all keep clothes and other things in the office."

Flexible hours help, too. Bryant often reports to work at 7:30 so his lunchtime workout can occupy a full hour and a half.

Often, he runs with Ray Velez, a communications officer for the Army Intelligence Command.

"We usually meet at 12 in the gym," about 200 yards from the office, said Velez. "As we dress, we discuss where we're going to go. Once we're out there, we know where we're headed. When we come back, we shower very quickly."

Running clothes -- as well as a brown-bag lunch -- go with Velez every day to work.

"I can usually eat right after running. That doesn't bother me," he said.

"I make my own lunch at night and take it with me," said Neary. "I just get behind my terminal . . . I guess I'm a compulsive; it's hard for me to go sit in a cafeteria or in a McDonald's and just eat."

"For the most part, I'm the kind of person who's never been used to eating in the middle of the day," Bryant said. "I have an apple when I come back -- that's all I need."

Many lunch-runners solve the food question by ignoring it. "I think the answer is that they don't have lunch," said lunchtime runner Jay Wind of Arlington. "That's why they're so skinny."

Wind, who lives three miles from his office at American Management Systems in Rosslyn, stays home with his baby in the morning while his wife runs.

At 11, he strikes out for Rosslyn, changes clothes at work, stays until 8 and runs home again.

"The place that I work has something magical for lunchtime runners -- lockers and showers," Wind said.

"When I started out, I actually carried a three-piece suit in my backpack. That got old very fast. Now I hang suits in the office, put shirts in my locker."

In some offices, lunchtime running has become so commonplace that returning to a desk with damp hair is practically a badge of endurance.

The lockers, showers and hair dryers at the Pentagon athletic club do much to return lunchtime runners to working order, said Neary. "You can put yourself back together very nicely."

"You don't worry about the fact that people come back with wet hair, or that in the summer they look like they walked through the shower with their clothes on," said Bryant. "It's kind of become a way of life."