Does holding your breath for a long time result in potential risk for brain cell damage because of repetitive episodes of oxygen deprivation?
Absolutely not. It’s not possible. People typically confuse an unconscious person-- a person who remains unconscious for six, seven, or eight minutes with irreparable brain damage. We’re holding our breath, but are completely conscious for that amount of time. If we don’t prepare adequately we will become unconscious. But, by doing the adequate preparation and the adequate ventilation, in effect you’re tricking your body into thinking you’re still breathing because you’ve packed so much oxygen into your system, that your body is just really efficiently burning through that. And if you’ve prepared well and you’re physically fit so that the respiration (the process of the exchange of gases) is efficient then it’s going to take a longer period of time before you need to breath.
What you have to do as somebody who’s pushing the breath hold ability is to overcome the contractions that you feel in your chest, which signals the need to breath. A good freediver will recognize when the contractions are something you can overcome and when the contractions are something that are severe enough that you need to exit the water and breath straight away to avoid a blackout. You can overcome them. You can fight them. Your body has this incredible reserve. It’s simply saying [it needs to breath] and at some point its going to [say] “If you’re not going to breath then I need whatever oxygen is left for the brain so I’m going to cut off your consciousness.” It’s like a breaker switch. It just cuts it off and all the blood now goes to the brain. It’s enough to sustain it for X amount of minutes. After that figure which tends to be six, seven, or eight minutes-- then and only then does brain damage occur. Brain damage is not going to occur in a breath hold situation where you remain conscious. Even if you’re unconscious for a couple minutes you’re not going to [expose] yourself to brain damage.
These were all concerns of mine and I wouldn’t be doing it if there were risks that were going to leave me temporarily or even permanently impaired. No way. I don’t take chances in life…Of course, there are naturally inherent risks that are associated with any breath hold activity and the single undeniably most important rule to freediving and to breath hold is that you never ever do it alone. You do it alone, you not only do expose yourself to possible risk of brain damage, but you expose yourself to a very clear risk of death. It’s possible, it can’t be ignored, but there is a very easy way to avoid it. The first, easiest, and most efficient way to avoid it is to dive with a buddy. That includes breath hold in the gym, sitting on your couch, in a swimming pool and of course freediving.
http://scuba.about.com/library/weekly/aa071201h.htm
