Pushing her limbs back and forth in the 93-degree water, arthritis patient Joan Hanson obeys a constantly changing stream of commands.

"You're a duchess!" shouts Michele Fergoda, her instructor.

Standing up to her shoulders in the water, Hanson strikes a noble pose and holds it -- until the next set of commands. And so it continues for close to an hour on a recent Thursday afternoon at the Noonan Family Swim Club in Del Mar.

Hanson, an Encinitas resident, is keeping her joints limber and muscles strong in the Arthritis Foundation's aquatic program.

"It's not only fun, it ameliorates your pain and the tension you have in your muscles and tendons," said Hanson, who has had arthritis for 10 years.

There's also a social aspect, said Fergoda, who is certified by the Arthritis Foundation. Arthritis patients, many of them elderly, enjoy the chance to meet other people. Since they all have arthritis, they have a common bond of understanding.

The Noonan Family Swim Club started offering the program just a few weeks ago, Fergoda said.

Celeste Luning, the swim club's manager, said the class is $30 for six sessions, held Thursdays at noon. People can also attend on a drop-in basis, paying $6 per session.

The classes are offered at six other North County locations (see accompanying box).

Use it, don't lose it

Hanson described her arthritis symptoms as "painful movement, not a lot of flexibility," and getting worse over the years. In the few weeks she's taken the class, Hanson said, she's already noticed improvement.

"With this class, I'm able to do a lot more without pain. It really improves your movement," she said.

Hanson has what she calls "garden-variety" arthritis. That would be osteoarthritis, the most common form. Arthritis comes in 130 forms, said Sandra Hayhurst, director of health promotion for the Arthritis Foundation's San Diego County chapter. The aquatic therapy is beneficial for them all.

Dr. Rashad Ansari, a Vista-based rheumatologist, said he encourages his patients to exercise.

"There's been a kind of sea change in thinking about arthritis," Ansari said. "It was thought for many decades that for people with arthritis, especially inflammatory arthritis, that rest was very important to calm it down. We've learned over the last decade or so that's exactly wrong. When you feel worse, it makes your arthritis hurt more."

In most cases, arthritis patients should do an hour of aerobic activity about four times a week, Ansari said. An hour every day would be ideal.

However, many arthritis patients are very badly out of shape, so even modest exercise hurts, Ansari said. That's where the aquatic program comes in, he said. It's a low-stress way to help condition joints and muscles. It can be the transition to a more active -- and less painful -- lifestyle.

Thousands participate

About 4,000 people in San Diego and Imperial counties take part in the Arthritis Foundation's aquatic program. Most of these live in San Diego County, Hayhurst said.

"You don't have to know how to swim," Hayhurst said. "You don't even have to get your hair wet," she said, speaking of women who don't want to ruin their hair styling.

Standing in the warm, shallow water, participants slowly stretch and bend. To get the most benefit, the exercises should be done twice a week or more.

This isn't aerobics. The emphasis is on preserving range of motion in arthritic joints.

Pools certified by the Arthritis Foundation are heated to at least 83 degrees. The air is also warm, so muscles don't tighten again once out of the water.

"The warm buoyancy of the water makes it a perfect environment for relieving arthritis pain and stiffness and improving range of motion for joints," Hayhurst said.

While supporting body weight, water is mildly resistant to movement, so people can build muscle tone with slow-motion exercises, Hayhurst said. And the warmth encourages blood flow to the extremities, nourishing the muscles and joints.

Fergoda and other Arthritis Foundation-certified instructors receive training so they teach the best exercises, and avoid anything harmful. Arthritis patients should not undertake an exercise regimen on their own, she said.

"We teach them anatomy and how the joints work, and how exercise affects motion of the joints," Hayhurst said.

Out of the water

Don't want to get wet? The Arthritis Foundation offers land exercises, too, such as tai chi. The foundation also teaches a self-help program so those with arthritis can best manage their disease. It's intended as a supplement to traditional medical care, not a substitute.

Those without health insurance can get help at three free arthritis clinics, Hayhurst said. Contact the San Diego chapter of the Arthritis Foundation at (858) 492-1090, or on the Web at http://www.arthritis-sandiego.org.

Contact staff writer Bradley J. Fikes at (760) 739-6641 or bfikes@nctimes.com.

Get in the Swim

The Arthritis Foundation offers its aquatic program at seven North County locations. The program provides comfort, but is not intended to be therapeutic. It does not take the place of exercise prescribed by a doctor or physical therapist. The locations:

Del Mar:

Noonan's Family Swim Club

15555 Jimmy Durante Blvd.

(858) 847-0794

Escondido:

Iceoplex Fitness & Aquatic

555 N. Tulip St.

(760) 489-5550 ext 309

Redwood Elderlink

1151 S. Redwood St.

(760) 744-5535

Fallbrook:

Fallbrook Physical Therapy

521 E. Elder, Ste. 106

(760) 723-8337

Rancho Penasquitos

Rancho Family YMCA

9410 Fairgrove Lane

(858) 484-8788

San Marcos:

San Marcos Senior Center

111 Richmar

(760) 744-5535

Vista

Bally Total Fitness Vista

1928 Hacienda Drive

(760) 806-6636