At Bally's gym they have this instrument called the body gem :
http://www.healthetech.com/bodygem/
That's the website. Very expensive to buy one... but I get it done free with my trainer. I have to wake up without moving around to much, no food after like 9 p.m. the night before, I go in and breathe into for about 10-15 minutes. Kind of uncomfortable because your nose is sealed off you look a bit silly, and you can only breath into that machine for the whole time.