[amihov]

Thank you Walrus. Thank you every body for participation. I believe that this is important topic and it is good idea to share knowledge about it . It will be safer for everybody if we better understand this.
The information is very helpful.
It seems like if you do short hyperventilation before the dive for maybe 20 sec you will be able to max out the oxygen level and still have plenty of CO2 in your body. This way you will be able to take advantage from the hyperventilation whit taking a big risk.
Sasho