Most modern people can testify that physical exercise is not a pleasant experience. Over 200 MDs, practicing the Buteyko self-oxygenation breathing method, and other health professionals performed many millions of simple body oxygenation tests (stress-free variation of the breath holding time test done after usual exhalation and without any pushing themselves) on thousands of people. It was found that:

1. Severely sick and hospitalized patients, who fight with death, have less than 10 s of oxygen in the body. Even walking is difficult for them and light physical exercise can be fatal.

2. People with mild forms of diseases (or those whose life is preoccupied with symptoms) have between 10 and 20 s for the body oxygen content. These people may try light exercise, but then they start heavy breathing through the mouth, and there are no health improvements after the exercise, while psychological stress is considerable. In fact, mouth breathing during exercise often triggers asthma attacks, stroke, heart attacks, etc.

3. However, when the same patients have over 20 s of oxygen, by practicing the Buteyko breathing method, they can moderately exercise with strictly nasal breathing and then they always feel better after the exercise and attacks are not possible (due to inhaled nitric oxide generated in nasal passages and higher CO2 in body cells).

4. When they finally get over 60 s for body oxygenation, these people start to crave physical activity claiming that they have too much energy and exercise becomes their bliss.

Body oxygenation depends mainly on our unconscious breathing pattern. When we breathe within the medical norms (the minute ventilation for normal breathing is about 6 l of air per minute at rest), the body oxygenation (exhale normally and hold breath but only until first signs of stress) is about 40 s. In fact, numerous medical studies conducted over a century ago found that ordinary people had up to 50-70 s of oxygen. It was before the industrial revolution, when most people had up to 6-9 hours or physical exercise, with nasal breathing only, every day.

Modern healthy people breathe more air (up to 9-12 l/min at rest) than the norm, while their body oxygenation is down to 20-30 s. In sick people, breathing is even bigger (10-20 l/min as dozens of western references revealed), but body O2 content is even less, or below 20 s, and this explains why exercise is hard for them.