Dear Dr. SerVaas: While I was being treated by a sports injury doctor, he commented that it is a good idea for everyone to take several very deep breaths upon arising in the morning and just before retiring at night. He said this opens aveoli (air sacs) in our lungs to allow more efficient oxygen uptake for each breath.I have never heard anyone else discuss this procedure. Is it valid?

Don Luke
Morgan Hill, California

Dear Reader: Breathing deeply helps your lungs and blood vessels function better, agrees cardiologist and heart transplant surgeon Mehmet Oz in his new book, You: The Owner's Manual.

Most people take very short, shallow breaths, the kind that simply comes from your chest, he explains. Taking deep breaths helps transport a potent lung and blood vessel dilator called nitric oxide from nasal passages to your lungs. As a result, oxygen saturation goes from 98 percent to 100 percent, and that two percent can make a big difference in how you feel.

For optimal lung function, Dr. Oz and coauthor Dr. Michael Roizen recommend taking ten deep breaths in the morning, ten at night, and as many as necessary in between to meet your body's oxygen demands.