How to measure the Control Pause
After your usual exhale, pinch your nose and count your CP (control pause) in seconds. Keep nose pinched until you experience the first stress or desire to breathe. If you release the nose and start breathing at the first signs of distress, you can resume your usual breathing pattern (in the same way as you were breathing prior to the test).

Do not extend breath holding too long. This is the most common mistake. You should not gasp for air or open your mouth when you release your nose. The test should be easy and not cause you any stress. The correct CP test does not interfere with your usual breathing.[Warning. Some, not all, people with heart disease, migraine headaches, and panic attacks may experience negative symptoms minutes later after this light version of the test. If this happens, they should avoid this test.]

Encouraging results of the clinical trial with HIV/AIDS patients
Russian doctors practicing the Buteyko breathing method had a clinical trial for a group of HIV patients with very encouraging results. For these doctors the index of oxygenation (CP) is the main measuring tool of personal health. I translated the official report about this HIV-AIDS trial.

Poor knowledge of English is still the main obstacle to faster information exchange and better understanding of this natural self-oxygenation therapy. However, some websites of Russian MDs have web pages in English...

Typical CP numbers for HIV patients
What are the usual CP numbers for HIV patients?
1-10 s of oxygen - severely sick, critically and terminally ill patients, often hospitalized, who take multiple medications.
About 15 s – mild forms of the disease;
About 20 s of oxygen – light forms of the disease;
Over 25 s 24/7 – no need for medication and no major symptoms.
Over 40 s CP – excellent health, including blood tests, parameters of the immune system, and mental well being.

The natural and stress-free CP test is valuable in numerous situations to check the effects of various factors, including allergies, nutritional deficiencies, exercise, etc. To increase tissue oxygenation and the CP (stress free breath holding time after exhalation) are the central goals of the Buteyko breathing method. What reduces body oxygenation? The main physiological factors include lack of physical activity, exercise with mouth breathing, sleeping too long and/or on the back, overeating, overheating, stress, poor posture and many others.