TACOMA, Wash. — On Tuesday nights, Greg Hoeker does headstands. On Wednesday afternoons, Edith Ketcheson balances with a chair.

TACOMA, Wash. — On Tuesday nights, Greg Hoeker does headstands. On Wednesday afternoons, Edith Ketcheson balances with a chair.

On Sundays, Bob Modarelli lies back and rests his legs over his head.

None of these Tacoma folks know one another. One is a doctor, one works in information technology; one is a delicate 90-year-old, one is a former marathon runner. They have nothing in common, except for two important things: They are all older than 50, and they all do yoga.

Most important, they all credit yoga for an improved state of health.

Yoga — that exercise that combines physical poses with breathing and meditation — has, of course, been around quite a while: in India, for thousands of years; in America, around 40. Yet the images it conjures up tend to be of young, lithe people doing impossible pretzel poses.

Ironically, though, the benefits yoga brings, according to doctors, teachers and practitioners — benefits such as reduced blood pressure, reduced stress, increased strength, flexibility and confidence, and help for chronic injuries and conditions — seem tailor-made for older bodies.

And around Tacoma, there are a number of people over 50 proving just that.

Greg Hoeker is a regular at four of the strongest classes at Source Yoga studio in Tacoma's North End. At 55, the computer programmer is lean and muscly, with a long blond ponytail and a killer headstand. Yet 17 years ago, he nearly died twice. The former marathon runner developed heart arrhythmia and had to quit marathons after his defibrillator went off while running.

"I tried to find other forms of exercise — volleyball, walking," says Hoeker, "but yoga gave me the most complete body-mind balance of any exercise. In a lot of ways I'm at a better level of fitness now than when I was running."

Hoeker has never had the defibrillator go off during class or home practice, but he sometimes gets lightheaded and knows when to ease off. Flexibility in backbends is another challenge, but most of the time he's one of the strongest in a class of mostly 30-somethings.

Hoeker is not the only one older than 50 doing headstands at Source, however. On the mat next to him on Tuesdays is 65-year-old Deane Knowles, who's comfy in the splits, and at the Thursday night power vinyasa class a sweat-inducing flow of advanced poses are David Kenworthy, 69, and his wife, Cheryl, 60. Sherry Williams, 60, teaches the class.

"People generally can do a lot more than they think they can," says Williams, a petite, trim brunette who looks more like 50 and teaches with a slightly boot-camp style of encouragement. "They suck themselves in and get stiff, and think they can't do things. Yoga is about opening up and reaching out, allowing yourself to come alive."

Williams is another who came to yoga from injury: After a lifetime of leading outdoor expeditions and sporadic yoga, she damaged a rotator cuff. This led her back to regular classes and teacher accreditation. She teaches two vinyasa classes and one meditation class at Source, as well as classes at All-Star Fitness. "If anything, I'm getting stronger as I get older," she says.

But for Williams, the real benefit in yoga lies not in the twists and lunges but in the mind. As a public defense attorney for Pierce County, she credits the breathing and meditation of yoga for helping her cope with "the chaos and stress" of the county's criminal division, and intends to teach stress-reduction meditation classes there in the near future.

"There's an incredibly high rate of alcoholism and dysfunctionalism in the legal profession. Yoga and meditation teach you how to dive deep and find an internal calm, no matter what's going on around you," she says. "The whole point of yoga is awareness, standing behind the waterfall of your constant thoughts and not getting caught up in it."

Not everyone, though, is up to headstands and arm balances, or even kneeling on the floor. Can you still do yoga with a less-than-ideal body?

Yes, say instructors, in fact, that's the great part about it. The hundreds of body positions that make up yoga can be modified in many ways. Blocks and straps can help where limbs can't quite reach; chairs and walls can provide support. Poses can be held at just the right point for that body, and there's no pressure to go any further. Yoga teachers are well-trained to suggest easier versions of poses, and encourage awareness rather than pushing.

Hal Meng is one of those teachers. Trained in viniyoga (a style based on individual adaptation), the 52-year-old came to yoga in 1981 on a chiropractor's recommendation after several car accidents injured his ankles, shoulders and back. Trained locally and in India, Meng now teaches classes around the South Sound, including general classes, those appropriate for conditions such as multiple sclerosis or cancer, and private yoga therapy. Meng's thick gray hair and mustache and solid, round frame don't seem like the characteristics of the average Lycra-clad yogi, but his calm demeanor does.

"I've seen a lot of improvement in my students, physically," says Meng before teaching an over-55 Wednesday class at the Point Defiance-Ruston Senior Center. "This type of yoga allows you to do it, no matter what stage you're at."

At his class, the stages do vary. All women, their ages range from 60 to 90, some floating effortlessly, others making smaller movements or grasping chairs for balance. Meng's classes vary too: At this one, half of the poses are done seated in a chair, with lunges becoming knees pulled to the chest and floor-based backbends now seated back arches. Standing poses are done with a chair for balance; forward bends use straps to reach the feet.

Edith Ketcheson has been attending that class since Meng began it five years ago. At 90, the retired nurse looks more like 70, with silver hair, soft skin and arthritic hands that can't straighten to form the traditional "namaste" prayer position that begins and ends class.

"I realized the importance of keeping active when I retired," says Ketcheson, who also works out at a cardio rehab class and has done tai chi. "I have a heart problem, but the breathing helps me."

Breathing? Yes. One big thing that makes yoga different from other exercise is that it unifies movement with breath mostly, expansive poses are done to an inhale, contracting or exerting poses to an exhale.

"One of the few things we have quick access to is the breath, and that instantly affects everything," Meng says. At one class, his breathing concentrates, with some meditation, on the gut area, to aid digestion and the immune system. At other times, deep inhalations are used to lengthen the spine.

One of the interesting developments in yoga for older people is that doctors are starting to see its benefits, and recommend it to patients.

As yet, the scientific evidence that yoga heals is small: Most studies come from India and are hard to access. Yet the evidence is there. The recently published "Yoga as Medicine" by Timothy McCall, M.D., summarizes more than 100 studies that document yoga reducing blood pressure, improving asthma, lessening obesity, managing diabetes, healing back pain, improving cholesterol levels and improving quality of life in conditions such as cancer and multiple sclerosis.

Two of those doctors who have begun prescribing yoga are Tacoma urologist Bob Modarelli and Puyallup rehabilitative physician Mark Tomski. Both attend class at Bikram Yoga Tacoma, a studio that teaches the Bikram Choudhury method of 26 simple, mainly floor-based poses in a room heated to more than 100 degrees in order to loosen muscles and detoxify through sweat.

"I was exposed to yoga before I began it myself, through (medical) courses," says Tomski, 52. "And there was a yoga and injury course in the last year in my academy. But it's only just now being mainstreamed as a prescription. I prescribe this for my patients — sometimes it's the only thing that can help muscular-skeletal issues."

Tomski himself has seen big improvements in his own health since beginning Bikram yoga two years ago: losing 20 pounds without dieting, changing his attitude to bad foods, lowering bad cholesterol and "normalizing good HDL for the first time in 20 years," he says. With more chronic conditions, Tomski says, yoga "can change your physiology, over time removing the need for so much medicine."

Modarelli, 66, also prescribes yoga, especially to older patients. "It's safe, it's good, it's exercise. I've had two artificial knees and three back operations, and yoga really helps me to get the best range of motion."

Some particular age-related issues are also addressed by yoga. Balancing poses (such as standing on one leg) increase bone density, says Bikram Yoga Tacoma director Yohana Knobloch. She adds that it also improves memory, and flexibility reduces arthritic symptoms and reduces the chance of falling or injury.

In fact, says Lisha Peacock, who directs the Puyallup YMCA's special populations activities (which include chair yoga classes similar to Meng's), older yoga students have testified that yoga has enabled them to live independently rather than in care facilities.

Are there issues for older yoga students to be aware of?

"We ask people with heart conditions not to come to Bikram," says Knobloch. "Other conditions may need a doctor's note."

Type 1 diabetics need to check their blood sugar levels before and after class, says Tomski, adding that anyone who's heat-sensitive might have difficulty with Bikram yoga.

June Annis, a 76-year-old who attends a gentle class at Source Yoga, points out that she's had to get over the self-consciousness of being the oldest in the class, and the need to follow visually when her hearing lets her down. Be aware that other than chair yoga, most yoga is done barefoot, on the floor.

Above all, says Greg Hoeker, don't set your expectations too high at the start, and know when to rest.

Increased health, strength and flexibility, improved memory, reduced stress, looking and feeling younger — yoga starts to look good. But, says Sherry Williams, the real reason goes deeper.

"Week by week, as my students discover their edge, they begin to glow," she says. "They don't have to be advanced poses. If you can move a tiny bit beyond your edge, you have access to so much more than what you think you have."