WHAT KEEPS REGULAR exercisers going? How do people overcome problems of time and motivation?

I wondered that here a few months ago, and heard from a bunch of folks who have found a bunch of ways to keep up some sort of fitness routine. Most people who wrote had a variety of suggestions; here's some of what they had to say:

In her battle with chronic back pain, Kay Flaisig, 40 of Olympia decided it boils down to a choice between "exercise" or "pain." But now she's worked out for so long it's become a natural part of her life. "I feel pretty dull and unenergetic without it," she says. "Besides, I lead a decaffeinated life, and my morning exercise is what I use to get started now." She also tapes TV shows to watch while stationary bicycling, and reads books while on the stair machine.

Louise Pietrafesa, 44, of Seattle (whose vanity license plate is LV2SWIM) swims with friends, sets short-term goals with small rewards (massages, lotion) and puts herself into a swimming competition once a year. "This is a great motivator because I don't want to come in last."

After years of paying club dues and exercise-class fees, Patty Hencz, 41, of Seattle decided to learn to teach fitness classes. "When I don't teach, I don't exercise," she says. She began as a volunteer teaching senior aerobics, and now has organized a professional network for people who teach seniors (Northwest Senior Fitness Instructors Association, 524-5384).

Paula Richardson of Seattle has found her ideal time for getting in a regular routine of twists, bends and crunches: "Every morning I clean my face, put on make-up base and use the time while it dries" to do her exercises.

Joanie Gray, 47, of Redmond is a single mother of two teenagers, has her own wallpaper-hanging business and goes to school part-time. Before she started school, she worked out for two hours eight times a week; now she heads to the gym two to three times and schedules a weekly five-mile walk with friends. Her motivation for all this effort: "Results! . . . Within two weeks, I am not exaggerating when I say I had a new body!"

Marian Gethmann of Wenatchee gets in a 30-minute ride each day on her stationary bicycle, "even if I sometimes divide it into queer portions." She may sound like a TV commercial when she says her secret to regular, faithful exercise is, "Just DO it," but I suspect she thought of it before Nike: Gethmann is 83 years old.

The award for motivation tips goes to Susie Feinberg-Stanton, 52, of Seattle. She sent a 19-page manuscript on motivation that she wrote 10 years ago after deciding, at age 41, to improve her physical condition. She gave herself 10 years to get in shape, which shows how serious she was about lasting change. Some of her advice:

-- Start off by reading books or signing up for a class to learn what to do.

-- Become your own coach.

-- Forget about "willpower"; instead, use your imagination to picture yourself doing the desired activities.

-- Make a schedule and follow it.

-- Break down exercise into small, easy pieces; she thinks of her one-mile swims not as 72 laps, but four groups of 18.

-- Start with a goal that's easily within your current ability.

-- Increase your routine in small steps.

-- Don't miss three workouts in a row.

-- Make your routine a fact, not a daily decision.

-- Stay flexible; if you have to postpone a session, reschedule it right away.

-- Don't let weather or other distractions become excuses to not work out.

-- Vary your exercise to avoid boredom.

And if all else fails, Keri DeTore passed along her great motivator: "Talk to your mother."

"Having her tell you, `No, you're not thin,' is a great way to get angry enough to work off the Haagen-Dazs."

Or to eat some.

Molly Martin is assistant editor of Pacific. ----------------------------------------------------------------- NOTEBOOK

Fitness news you can use

OK, Don't Eat Your Veggies A new book makes a strong case for parents to ease up when it comes to what their children eat. "Let Them Eat Cake! The case against controlling what your children eat" is written by pediatrician Ronald Kleinman and pediatric psychiatrist Michael Jellinek. It's $19.95 from Villard Books.

It's Not the Hardware According to Edward Jackowski, a member of the American College of Sports Medicine, six of 10 people who buy fitness equipment never use it after six months.

Just Tape It If you work out to videotapes, check out "The Complete Guide to Exercise Videos." For 250 exercise videos, this mail-order catalog lists magazine ratings, staff favorites, type of workout, time of exercise segments and total session, target audience and other details. Call 1-800-433-6769 or write Exercise Video Catalog, Dept. G., 5390 Main St. N.E., Minneapolis, MN 55421.

Painful Memories "No pain, no gain" may be passe as an exercise maxim, but most everyone who works out has stories about their encounters with fitness-related pain. Tell us your most memorable ones: Send to Pain, On Fitness, Pacific Magazine, The Seattle Times, P.O. Box 70, Seattle, WA 98111, or e-mail mmar-new@seatimes.com