SACRAMENTO, Calif. - The day starts off with a rundown of the rules: No talking. No eye contact. Keep your gaze cast downward, save for an occasional glance at the teacher.

No, this isn’t Saturday high school detention. Quite the contrary, this should shape up to be a day of rewards, not punishment. An opportunity to clear one’s mind of stress and worry - and practice being aware of the present moment. It’s a silent retreat teaching Mindfulness-Based Stress Reduction, a secular integrative medicine technique that’s gaining popularity as a way to relieve stress and boost concentration.

An amalgamation of ancient Eastern practices, MBSR is increasingly being taught in public schools, hospitals, the military - even prisons. Physicians are referring patients to MBSR programs as an alternative to anti-depressants.

Mindfulness meditation retreats have long drawn well-heeled bliss-seekers who spend top dollar for teachings held at forested, secluded compounds in Marin County or upper New York.

During one recent Mindfulness-Based Stress Reduction silent retreat, a group gathered on a Saturday in December in a nondescript donated office space in an industrial office park in El Dorado Hills, Calif. And the people sitting in straight-backed chairs arranged in a circle (to feel safe) were patients referred by doctors, not the benefactors of Rodeo Drive or Fifth Avenue.

Ten participants, including teacher Gayle Wilson, prepared to immerse themselves in the practice of mindfulness, through concentrated breathing, yoga, Qigong (an Eastern-based practice involving slow, contemplative movements), and several types of meditation, all designed to ease their pain, whether mental or physical. Among the techniques was something called a body scan, during which practitioners lie down on yoga mats while a teacher gently guides them through a mental inventory of their body parts.

Why no speaking or looking one another in the eye? Because, Wilson says, “these ground rules allow us to go more deeply into the meditation practice and to conserve our energy for the work of mindfulness.”

Achieving mindfulness means being fully aware of living life in the moment, rather than ruminating about past troubles or anticipating future events. The program was developed by Jon Kabat-Zinn at the University of Massachusetts School of Medicine in 1979, and is used in more than 250 medical centers across the nation, including Harvard Medical School, Stanford University, the American Red Cross and the Mayo Clinic. Even Google has adopted the program for its employees.

The Mindfulness-Based Stress Reduction program has stood up to peer-reviewed research for 30 years, says Wilson, who calls it “the gold standard” for helping relieve all manner of stress-induced health problems.

Research published this month in the Journal of the American Medical Association examined 47 studies on meditative techniques, concluding that mastering mindfulness makes people better able to cope with life’s everyday challenges, as well as stress, depression, anxiety and pain. The positive effects, which outperformed mantra meditation, were seen across multiple studies.

Dr. Dan Siegel, a clinical professor of psychiatry at the UCLA School of Medicine, agrees. “Studies of MBSR have consistently demonstrated its effectiveness as a health promotion activity,” he said. “It can help to disentangle our minds from ruminative thoughts, repetitive destructive emotions and impulsive and addictive behaviors.”

Mindful meditation takes advantage of the brain’s neuroplasticity, or its ability to adopt new thought processes after being exposed to them again and again. To put it simply, MBSR behaves a little like Mr. Clean of the brain, scrubbing out those stubborn negative or what-if thoughts and leaving the practitioner alert and unencumbered. Stress-related repetitive thinking can contribute to depression, high blood pressure and other medical conditions.

Experts warn that taming the wandering mind is challenging and takes practice. Some people struggle with what’s sometimes called “monkey brain,” which the online Urban Dictionary describes using this anecdote: “When you begin reading a page, and blank out thinking about other things. You finally come to, realizing that you read the whole page without ingesting a single word.”

Or, as MBSR participant Bob Relei, 65, of Folsom, Calif., says: “It’s my mind. It’s just working all the time. It is very hard for me to shut it off.”

Relei is retired from the San Francisco Fire Department, where for more than 30 years he thrived in a fast-paced, adrenaline-based environment. “I miss it,” he says. “Back then it was like everything was go, go, go. Get things done.”

Relei’s adjustment to retirement was difficult, and after he suffered a hernia - “I tried to lift something I shouldn’t have” - and botched surgery, he was left in constant pain for six months. It didn’t take long before depression set in, he said. Eschewing antidepressants, he was referred by a psychiatrist to Wilson’s program.

As a textbook, Wilson relies on Kabat-Zinn’s “Full Catastrophe Living - Using the Wisdom of Your Body and Mind to Face Stress, Pain and Illness,” first published in 1990 and updated last year. Kabat-Zinn likens mindfulness to Buddhist meditation without the religious teachings, and Wilson completed years of training in his methods. Over the eight-week course of 27 hours of instruction, she meets with the group once a week to go over the meditations and readings, to share exercises and encouragement.

The silent retreat held in late December opened with Wilson instructing the group on mindful breathing or focusing only on the breath as it goes in and out.

Then, everyone did a mental body scan, paying attention to every part and relaxing any stress-related tension.

Afterward, the group moved outdoors and practiced under an unseasonably warm sun, with a light breeze tickling the leaves still clinging to their tree branches. Wilson coached the group through a series of Qigong exercises involving sweeping, stretching motions that invited the sun’s energy into the body, honored the fluidity of the sea and evoked an encounter with a dragon.

A walking meditation followed, during which participants focused their minds on the heel-toe, heel-toe rhythm of placing one foot carefully in front of the other.

Lunch was next, and everyone was sent to a quiet place outdoors to contemplate each bite as they brought it up to their mouths. Mindful eating, as it’s known, is one secret to slowing down mealtime, potentially resulting in eating less and losing weight. Focusing on the texture, smell, taste and consistency of food takes time and allows your digestive system to signal to the brain that you are full so you don’t overeat.

Wilson then led the group back to their chairs for the “mountain meditation,” a 20-minute sitting during which she instructs:

“We use the image of a mountain to help us remember what the sitting meditation is all about. The image is uplifting, suggesting as it does that we sit like mountains, feeling rooted, massive and unmoving in our posture. Our arms are the sloping sides of the mountain, our head the lofty peak, the whole body majestic and magnificent. We are sitting in stillness, just being what we are - just as a mountain ‘sits there,’ unmoved by the changing of day into night and the changes of the weather and of the seasons.”