On swimmers and snorkels, why it's a bad idea to race with one

No, this isn't a bag on snorkel thread.  If you have a medical condition and can't move your neck enough, that's one thing.  

But there have been a few threads re: snorkels recently, and to race with one as a crutch, or aid, is actually doing you more harm than good and potentially seriously affecting your performance.  Add the stress of cold water, wetsuits, crowds, they are even worse.

The air around us has about 21% oxygen.  Exhaled air contains about 17% oxygen plus 4% CO2 (as opposed to something like .4% of CO2 in air), plus some other gases, mostly nitrogen.  Obviously, oxygen is the one we're concerned about getting as much as we can.  CO2 is heavier than air and in enough concentrations is deadly.  

The way snorkels are designed, they have a pocket below the mouth which creates an area called dead space.  The exhaled CO2 collects in this dead space and, when you inhale, you inhale a much higher percentage of CO2 than exists in surrounding air, and, as a result, less oxygen.  That's why some people experience the feeling that they can't get a full breath when snorkeling.  You are simply not getting the oxygen you need.  In a race situation, you are clearly not doing yourself any favors by using a snorkel and, in fact, you are preventing yourself from getting adequate oxygen exactly when you need it most. 

In fact, snorkels are advertised as a way to "increase CO2 tolerance."   http://webcache.googleusercontent.com/search?q=cache:wH2WKFvi9a0J:www.all3sports.com/product_info.php%3FpName%3Dfinis-swimmers-snorkel+swim+snorkel+CO2&cd=9&hl=en&ct=clnk&gl=us

Here's a short discussion re: snorkels, swimming and CO2

http://forums.usms.org/showthread.php?p=109713




Edited by ChrisM 2010-09-02 8:49 AM