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Oct 03, 2006
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A little Advice about snorkeling and diving
Most people can hold their breath longer than they think. If you follow a few basic steps you will probably be surprised of what you are capable of. First however, you must have the basics down. You will need a pair of fins and a quality mask and snorkel. (No cheep foodland $20 set). I recommend Surf-N-Sea or Deep Ecology for buying gear - both are dive shops located in Haleiwa. You should be comfortable enough using your gear that snorkeling becomes second nature. If you have troubles with a leaky mask or snorkel
feel like you are struggling to get air
you panick easily, then you need to get some more experience or some new snorkel gear.
For those of you ready for more advance diving here are a few tricks that will increase your underwater time.
Body temperature plays a big part in the use of oxygen. If you are cold or shivering you heart must beat faster and use more oxygen to keep you warm. If you want to impress someone - time yourself underwater when you've been sitting in a hottub for a while.
Take a couple prep-dives when you get in the water.
Since you've probably been sitting in a car or bus your body is only taking and using enough oxygen to get by on. When you get in the water you will want to use and circulate as much air as you can. Once you get in and are comfortable with your gear and setup, hold your breath for as long as you can. (Which will probably only be 20 or 30 seconds). When you breath again you should be panting pretty heavily. Float for a few minutes and rest for a bit while you catch your breath then repeat the process at least one more time. For these prep dives and subsequent underwater dives you suffocate your system of air for a bit. It counters the problem by flooding itself with air when it becomes available. You will feel your heart beat go up as your heart circulates the oxygen-rich blood around the body.
The passage from your lungs to the end of the snorkel is called dead air space. Dead air is the air that you breath out - rich in carbon dioxide. Each time you breathe in through the snorkel you get all the dead air that you exhaled from your previous breath that was sitting in your throat, mouth, and snorkel. Usually when snorkeling, especially when nervous or uncomfortable it's natural to take short quick breaths. When you do this you move the same air up and down in your throat and snorkel which results in a poor supply of oxygen. If you can get in the habbit of breathing deeply you will get a fresh supply of oxygen for each breath and your lungs will work at full capacity to get oxygen in the blood. (Sometimes people try to breathe without the snorkel to minimize the dead air space, but it takes more work to keep your mouth above the water and takes more oxygen anyway. Just use the snorkel - it will only help.
After you do a couple warm up dives to get the oxygen circulating, swim (at the surface) to the spot you aim to dive. Float at the surface for a few minutes and breathe deeply. This will help slow your heart rate down and enrich your blood with oxygen. Just before you dive take about 6 to 8 quick, deep breaths and make your dive.
Out of all the activites I (Merlin) have done, skin diving has brought me the most near-death experiences. It must be done with caution and wisdom.
Moving a lot of air in and out of the body begins to shut off the system alarm for air. It helps you hold your breath longer, but instead of getting the burning "I need air" feeling in your lungs & throat, you begin to lose consiencesness and black out. Also, holding your breath works pretty well for a while, but after about an hour of diving, your body will usually begin to tire of flooding and holding air and begin to exhaust it's capabilities. After a time you will not be able to dive through caves that you were able to earlier in the dive.
Avoid snorkeling alone. Never dive through caves alone. Be cautious of one another.
Even if you are familiar with the caves and terrain, avoid cave diving at night. During the day the sun lights up the ends of each cave. You can usually swim down, look into a cave and see the exit before even entering it. This gives you an idea of the length of the cave and and weather you are capable of swimming through it. At night you only have your flashlight which illuminates the area around you. You have to guess which direction to go to exit the cave. Things look very different at night and it's easy to get dissoriented. (I experienced blackout one night trying to get out of a cave I had done dozens of times during the day.)
Oct 12, 2006
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I have not taken A&P recently, but from my understanding our body's primary trigger to breath is not low oxygen levels, but high CO2 levels. A person's body who has damaged CO2 chemo receptors (such as a smoker) will then have unconscious breathing triggered by chemo receptors that respond to low O2 levels. As an EMT, patients with chronic obstructive pulmonary disease (COPD) could not be given very much supplemental oxygen because it would actually depress their breathing instead of improving it. Their bodies were used to high blood CO2 levels and since there was now plenty of blood CO2, the body would have no indication that breathing was necessary. Is this relevant? I don't know. But I think that means our first urge to breath isn't from low O2, but too much CO2, and that is why we can hold our breath longer than we realize. Still, Merlin is half fish and knows what he is doing. His advice is solid even if the logic and physiology needs some clarification. Oh, and don’t shop Surf ‘n Sea if you can go to Deep Ecology instead. Deep Ecology is a truly ethical operation, the money you spend there is a partial investment in the habitats you plan to dive.
Oct 18, 2006
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wouldn't high CO2 be pretty much the same as low O2 since when one is high the other is usually low and vice versa? I'm no EMT though :( Awesome post Mer! couldn't agree more. Especially with the night diving. I almost got lost one night in the hook. I had two choices and luckily I picked the right one. Another time I followed you guys in without a light and didn't get a very good breath to start. I've never had so many chest convulsions in one dive than on that one and I came up gasping (unfortunately right in front of your video camera). One thing that I think helps me stay down longer is focusing on making every stroke and kick count. Instead of worrying about getting down and going through the cave as fast as I can I try to just relax and take long efficient strokes. seems to help but I'm no expert :)
Jan 17, 2008
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Kathryn (Higgins) Osmond
Oh my gosh... I love this blog. It reminds me of THE time at night- remember? I followed you INTO the coral and managed to turn around and get out on accident... But you were GONE for what felt like 10 minutes. Yeah. From experience, night diving is definately the scariest. Never go into a cave you don't already know by heart. (if at all). I do have a little something to add though to "how do dive like a pro." The best dive of my life- AND the best rock-walk was done on a day that I SUPER hydrated myself. I noticed I could hold my breath almost twice as long as I had ever been able to before. On top of that, I could swim for almost another hour before getting exhausted. What I mean by -super-hydration- is this. We left around noon for the cove and from 10 to noon, I drank 2 two-liter bottles of water. :) (a lot i know.) but like I said... I had way more energy than ever. *shrug* just another side note. *cheers, muah* -Kath
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