Can a deep-breathing device help lower my blood pressure?

Q. I've heard you can lower your blood pressure by using a breathing device called Resperate. Do you know anything about this?

A. A growing body of scientific research shows that exercises to slow breathing can lower blood pressure. Experts don't know the precise mechanism, but most theorize that slow breathing may turn down the autonomic nervous system (ANS), which helps regulate functions such as heart rate, blood pressure, and digestion. When activated by stimuli such as stress, the ANS causes muscles around small arteries to contract, narrowing the arteries and increasing blood pressure. Slow breathing may calm the ANS, allowing these small arteries to expand and decreasing blood pressure.