Forever Fit : Senior citizens who exercise regularly credit it with helping to keep them healthy in both body and spirit.

Annie Swartz, 81, of Westlake Village is learning the “cowboy cha-cha.” While the rest of the leotard-garbed women in the Staying Fit class stomp, step and sashay to the Western song, Swartz, a tiny white-haired woman in a mint-green pantsuit, moves to her own gentle beat.

She waves her arms and glides her gold sandals across the floor of the Agoura Hills Recreation Center multipurpose room.

“Isn’t this fun?” she asks when the music stops and the class folds up their exercise mats. “I don’t follow directions that well, but I try. I take classes in yoga, exercise and dance, then I swim. When you’re old like me--I’m going on 82!--you have to. Exercise makes my heart beat, my blood pump and my face flush, so I don’t have to put on rouge. It makes me feel young! OK, sweetie, I got to go.”

Staying Fit, which combines low-impact aerobics, calisthenics and dance, is the most popular offering. On some days, there are as many as 35 participants, most in their 70s and 80s.

“This is a wonderful outlet,” says Staying Fit instructor Barbara Blewett, 53, who has taught senior fitness classes since 1984. “Many people have taken my class for several years, and I can see they are much more limber and agile in body and spirit. People who keep busy and active have a healthy body and a healthy mind. The two go hand in hand.”

While only about a third of Americans 65 and older exercise regularly, physical activity is especially important for people in that age group, according to the President’s Council on Physical Fitness and Sports. Much of the frailty associated with aging is actually the result of muscular disuse and can be halted--and in some cases, even reversed--through regular exercise.

Helen Hollenbeck, 68, of Agoura Hills has attended the Staying Fit sessions twice a week for the past six years. “I feel better,” she says. “I have made very good friends. I maintain my weight, and I have firmed up. This is good for my physical and mental health.”

Programs for Seniors

Many parks and senior centers throughout the San Fernando Valley offer a variety of exercise programs geared to senior citizens. A sampling of what’s available:

Agoura Hills Recreation Department, 30610 Thousand Oaks Blvd. (818) 597-7361. Swimming, tennis, aerobics, calisthenics, tap dance, polka dance, folk dance, golf, yoga. $25 yearly registration includes all exercise, sports, games and other activities. Canoga Park Senior Center, 7326 Jordan Ave. (818) 340-2633. Exercise classes. Donations appreciated. East Valley Multipurpose Senior Center, 5000 Colfax Ave., North Hollywood. (818) 766-5165. Exercise, including classes for people with arthritis. Donations appreciated. Jewish Family Services (non-sectarian), 12821 Victory Blvd., North Hollywood. (818) 984-1380. Chair exercise and several dance groups. Free. Pacoima Senior Citizens Multi-Purpose Center, 12550 Van Nuys Blvd. (818) 899-9548. Exercise and stretching. Free. Sepulveda Recreation Center, 8801 Kester Ave., Panorama City. (818) 893-3700. Exercise. Fee is $1. Sherman Oaks Senior Citizens Center, 5056 Van Nuys Blvd. (818) 902-2146. T’ai Chi, $1 per class. Walking classes, free. Sunland Senior Center, 8640 Fenwick St. (818) 353-9571. Stretching, exercise and walking. Free. Van Nuys Senior Citizens Multipurpose Center, 6514 Sylmar Ave. (818) 781-1101. Exercise. Donation appreciated. Robert M. Wilkinson Center, 8956 Vanalden Ave., Northridge. (818) 701-0141. Jazz and tap dancing, aerobics, walking, exercise, yoga, T’ai Chi. Free.

Before You Start to Work Out

Want to start working out? Here are some tips from the President’s Council on Physical Fitness and Sports, and the American Assn. of Retired Persons:

* Check with your physician before beginning an exercise program. * Exercise at least three days a week. * Wear comfortable, loose clothing. Light colors will keep you cooler in the summer; a hat that provides shade is also a good idea. * The late afternoon and the early morning are good times to work out. Do not exercise strenuously during extremely hot weather or within two hours after eating. * Breathe deeply and evenly while exercising. * Rest whenever necessary. * Include aerobics, as well as strengthening and stretching exercises, in your regime. * Begin slowly, about five to 10 minutes a day. Gradually increase your activity level up to about 25 minutes.

WHERE TO GO

What: “Pep Up Your Life,” a fitness booklet with information for beginning an exercise program, as well as specific illustrated examples of exercises suited for senior citizens, including several that can be done by people in wheelchairs.

Location: Write the American Assn. of Retired Persons, 601 E St., N. W., Washington, D. C., 20049.

Price: Free.