Fred Rosenberg and Edith Atkin hadn't seen each other in 37 years until last week, when they met during a walk -- at a shopping mall.

Atkin, of Silver Spring, who describes herself as "a grandmother with a 19-year old grandson . . . . I was a child bride," and Potomac resident Rosenberg, 69, used to go dancing at the old Jewish Community Center on 16th Street NW. They are still hoofing it, but at a different pace.

They walked into each other at Wheaton Plaza, where, before the stores open for business on most mornings, scores of senior citizens converge to stride between the Woodward & Lothrop and Montgomery Ward stores and back, a round trip of a quarter-mile.

Mall walking for exercise is said to have caught on among older persons at a number of enclosed shopping centers around the country.

In Harford County, north of Baltimore, one mall popular with older walkers is known as "cardiac alley." At Wheaton Plaza, walkers who register with a Red Cross volunteer nurse at the information desk Monday, Wednesday and Friday become certified, badge-wearing members of the Rise & Shine Walking Club.

The Rise & Shiners supply the nurse with medical information, in case of an emergency. Since the club began officially almost a year ago, 442 walkers have registered.

"It's like a family," said one woman, who walks with her husband, a retired accountant. "It's nice. You hear, 'Good morning. How are you?' If you miss a week, people say, 'Where were you?' "

The walkway is level, the climate controlled and the company congenial.

"I can tell it's springtime, because there are a lot of couples walking," said Wheaton Plaza's marketing manager, Ann Korff. "It's a darling bunch of people, very cute, very earnest. Sometimes, the men all walk together in clumps, or the women all walk together in clumps, and there's quite a bit of repartee."

A few wear Walkman headphones and march to their own drummers. Retired military man Rodgers Harris, one of them, listens to classical music. But most walkers promenade with friends or spouses.

"We just finished our mile," said John Wheeler, 68, cooling down from the exertion while he sat with his wife Dorothy, 64. "I'm doing this for heart recuperation," said Wheeler, who recently had triple heart bypass surgery. "I thought I had it made playing golf six or seven days a week. But my doctor said that's not the kind of exercise I need, and to take 20-minute walks."

Some walkers arrive as early as 7:30 a.m., an hour before the Red Cross nurse, and some stay until the stores open around 10. Many end their mall walk with coffee at Peoples Drug Store, or at Burger King, where Martin Blacksin, 68, and his buddy, Harold Giberman, 67, ended up the other day. Blacksin, of Takoma Park, said he used to walk his dog in the park but began mall walking with his friend after Giberman had a heart attack.

"My doctor says, 'Harold, get some exercise, don't get aggravated, don't do this, don't do that,' " said Giberman, a retired junk dealer who has had six heart bypass operations and lives in Wheaton. So he walks, in yuppie-style running shoes his wife bought for him.

"It's like the lonesomeness of the long distance runner," Blacksin observed. "You run by yourself, there's no competition, whereas here time passes real fast. You make laps real fast with the buddy system."

But the fastest of the four dozen walkers that day was going it alone. "This is doctor's orders, so I don't walk with anybody," she said without breaking stride.

"She don't stop for nothing, she's a good walker," said Irvin (Buddy) Hayman, 68. "She makes her laps and then she leaves, all business. She'll say good morning to you, but that's about it.

"There's a racehorse for you," he said, pointing out another walker. "They're racehorses. They fly."

Hayman, who had cardiovascular surgery 10 years ago, rests on a bench after each lap. "I'm a sitter," he explained.

Wheaton resident Charles Simons, 75, comes for the most part to sit and watch the walkers pass.

"I admire them," he said. "I'm just sorry I can't walk as long as they can. I walk up and back and I'm tired. I rest and do it again."

His wife Rose, also 75, walked by at a brisk pace. "I've been doing aerobic dancing for 10 years," she said. "I can kick up my heels with everyone else. Here, I walk for an hour, approximately three miles . . . "

Exercise was not the main motivation behind Fred Rosenberg's appearance at the mall. Semiretired, he works part-time for a construction company that was remodeling a store inside Wheaton Plaza.

"I walked here a little the other day," he said. "I would be walking today, but my leg's sore. I just got out of bypass surgery six weeks ago."

Then he spotted Harold Halpern, another familiar face. "This is one of the best walkers in the country," he said by way of introduction.

Halpern, 69, owned a shoe store at the White Flint mall on Rockville Pike until his retirement Jan. 31. "I've been walking here ever since," he said.

Halpern said he and his wife Anne, 67, usually start walking around 7:30 a.m., "when they're mopping and cleaning. They don't bother you."

One mall worker was watering plants, seemingly oblivious to the wave of walkers passing by.

But Clay Igleheart, 30, a carpenter building a booth for a stuffed-animal emporium, remarked that he and fellow workers "see them in here every morning, making their rounds, getting their blood circulating, I guess. They make me dizzy."

As 10 a.m. approached, others who had come to shop joined the walkers. "I am walking," said Gerry Cain, 32, pushing her two-year-old daughter, Sarah, in a stroller. "But I'm here to shop and everything is still closed."

Cautioned Hayman, "If you get here too late, the kids take over and it's too tough to walk." Indeed, soon enough teen-agers were sprawled along the benches and gathered around the video games in the Peoples drugstore.

Giberman and Blacksin finished their coffee at Burger King, and the drugstore's regulars, five women and two men, came and went.

"They come and get their water and coffee," said fountain food manager Mary E. Grubbs. "We expect them every day. It's nice to have them here."