This is the second installment in a three-part series on low back pain and exercises to help prevent or alleviate it.

Each week we offer five exercises that can be done at home, with little or no equipment.

The series:

• Jan. 14: Stretches and exercises to strengthen the back.

• Today: Yoga

• Jan. 28: Pilates

Low back pain is one of the most common health problems among Hawai'i people. In fact, most doctors will tell you that it is the second most common complaint after colds and flu. It can affect people of all ages and every profession, from sedentary office workers to highly physical laborers.

In January, when so many are focused on getting fit, low back pain often results from overzealous or improperly done exercise.

"Exercise is important in between episodes (of low back pain) and to prevent the next one," says Dr. Bernard Portner of Portner Orthopedic Rehabilitation Inc. (www.portnerorthopedic.com).

Portner cautions that it's important not to start a new exercise program while in severe pain; it's best to wait until the discomfort has eased.

Dozens of techniques can help with low back pain. Among those Portner uses: "traction, mobilization, manipulation, medications and injections — whatever it takes.

"Once the patient is on the road to recovery, then I'll begin to introduce exercises," the doctor says. "If you start too early, it can give you the opposite effect."

Portner adds that it's best to start a little at a time. "Don't go into a new exercise program five days a week," he advises. "Maybe start with once a week."

"There are many things you can do to lower your chances of getting back pain," the North American Spine Society's Web site advises. "Most back problems will get better on their own. The key is to know when you need to seek medical help and when self-care measures alone will allow you to get better."

Low back pain can come from the spine, muscles, nerves or other parts of the body, and can have various causes, including poor posture, pregnancy, lifting a heavy object, a sudden movement, sitting in one position for a long time, injury or accident.

Obesity and smoking are also significant risk factors, Portner said.

Yoga is a form of exercise often recommended to people with low back pain. According to a 2009 study cited in the journal Spine, "Yoga therapy can reduce pain and improve function in people with chronic low back pain."

Regular yoga practice can increase flexibility and strengthen the muscles that support the spine, as well as muscles in areas that can cause back pain, such as the hips, hamstrings and butt.

Portner often recommends yoga to his patients with this caveat: "The guideline with yoga is to not do what hurts. Good instructors know this. Forget the 'no pain, no gain' thing; it's not true for people with back pain."

Of course, if experiencing severe persistent pain, especially while at rest, you should be seen by a physician immediately. Also, if pain is chronic (lasting three months or more) you should be seen by a physician.

Yoga instructor Mary Bastien of Open Space Yoga (www.yogaopenspace.com) said many of the low back problems she sees among her students are caused by poor posture.

"If your foundation is off, it will affect everything else," she said. "Yoga works with stabilization and gets your foundation correct. It lengthens and stabilizes muscles to help support the back."