MIAMI -- The cold and flu season is almost here. There's no cure for the common cold, but a common form of exercise -- yoga -- can help prevent the sniffles.

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"Your immune system impacts your overall health. So, we're looking at what we can do to make sure your immune system is intact," said Dr. Theri Raby of Internal Medicine.

What Raby often suggests to patients is something they can't get at the pharmacy.

"I prescribe yoga on a regular basis," Raby said.

A Washington State University study recently found that breast cancer patients who practiced yoga three times a week felt less pain and were less tired and fearful. Their blood tests revealed they had noticeably less of the stress that damages the immune system.

"We know we have this one particular immune system protein that is a marker for stress," Raby said. "We have found that it can actually decrease that particular protein in the body."

NBC 6 asked fitness expert Sergio Rojas to show us some immunity-boosting yoga moves. First, the fish pose.

"Putting the crown of head onto the floor -- opens up the chest and brings in more oxygen, circulation," Rojas said.

The body's cells use oxygen constantly for basic functions. More oxygen gives the immune system more ammunition to fight off germs.

The downward dog pose is a basic yoga pose that stimulates the lymph system. Lymph fluid carries immune cells throughout the body.

Rojas said the child's pose creates a relaxed state, which lowers levels of stress chemicals, replacing them with feel-good endorphins.