Seek medical advice before using.

Deep breathing does not increase the amount of oxygen absorbed into the blood, it does decreases the amount of CO2 held in your blood. CO2 is the mechanism, when levels rise high enough, that forces involuntary breathing. When it is too low, your body may experience a reduced amount of oxygen because reduced CO2 allows you to not want to breath. This is a notable problem with divers who seek to hold their breath longer. Reduced oxygen in the blood can cause damage to your brain, organs or even death. Please consult your doctor before attempting these exercises. Sure this not a divers program. however you should be aware of how deep breathing effects the levels of oxygen and CO2 in your blood and the risks associated with it.

danilko1 about Breathing Zone Free - Relaxing Breathing Exercises