Well, I have to hold a breathy "s" sound for 30 seconds. I hope you know what I'm talking about... I take my breath, and then I'm slowly releasing it and making the sound "s". The problem is, that I can't hold it longer than 15 seconds. I have had some breathing problems, and I'm alergic to some stuff that affects my breathing, and when those 15 seconds pass, I still have enough air to make it to 30 seconds, but I need to take a breath, and can't hold it! I have enough air in me though, just that after not breathing for a while (15 seconds) I get dizzy and have to take a breath immediatly! What should I do? Just practise?