I'm sure this can phenomena be flowcharted, and as a result lead us to what we are after - how to avoid.

Swim and Exceed your VO2 Max
Leads to Hypoxia and/or
Leads to Hyperventilation
Incorrect and out of control CO2 levels in the body -> Hypercapnia

Either way, the respiratory system and CO2 is now out of control and this results in Vasoconstriction of different types. Perhaps Hypoxic Pulmonary Vasoconstriction where the lungs won't function properly, the legs are going to be the first muscles to shutdown (as witnessed). I think something is going on with the lungs because in this state you feel like you need ridiculous amounts of air and can't get it.

And then the blood chemistry changes too, further contributing to the ( total) system shutdown.

To stay concious blood flow to the brain needs to be maintained so I think a tight swim cap is a bad thing as is over-temperature. Cool water over the head is OK.
What else can be done I wonder...

Also - http://scuba.about.com/...And-Scuba-Diving.htm

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Thank you for your thoughtful and knowledgeable response.

I'd like to learn more on how the OP managed his swim start strategy. Did he remember to breathe? Also, in the excitement of the moment, did he go out for 4 minutes with only taking in a few shallow breathes? It's also not clear if he had a good warmup.

Thank you again for your response. You've raised some valid points. Also, wearing a wetsuit would only add to these problems.

Well, in my case I started with about 180 folks. Maybe started close to MOP but drifted to BOP pretty quick. I bumped into a few people but nothing serious. As I recall, I was breathing to both sides for about 25 m although I was also looking up a lot. I then switched to breathing on 1 side, every stroke (or is that every 2nd stroke?), in any case every time my right arm went back I took a breath on that side. This is a normal breathing pattern for me.

Was unable to breath deeply although I'm not sure what it was like at the start but once the wheezing started, no deep breaths for the rest of the day. At that point I didn't have any Ventolin, now have an Rx for it and for the last couple of wetsuit practices I did I used that first. Did not have a repeat attack - just lack of fitness causing me to stop and rest but after doing so I could swim normally again.

So in summary, I suspect a series of things triggered an attack. Tight wetsuit, first Tri in it, insufficient warmup. I used the same wetsuit yesterday but did more swimming warmup (still only 50 to 75m) and took a shot of Ventolin before going out. Only Practice swimming but was able to start feeling stuff in the water (fit of wetsuit, how it felt when extending my arm etc.).

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BC Don
Pain is temporary, not giving it your all lasts all Winter.

I don't know how to say this nicely, but some of the responses above are ludicrous. I think you know you should trust your own doctor's opinion and advice far above any guesses suggested by us, the peanut gallery.

Now getting back to the subject at hand, I wonder if most/all of the recent [swimming related adverse health events in triathlon] are related to swimming simply because it is the first leg of triathlon, and the events are more likely exercise-induced rather than swimming-induced.

I don't agree, i suspect they are swimming induced and to simply discount them as first leg events is as you mentioned "ludicrous". I did some rough tests in my 2nd swim today and do I believe this is all starts as CO2 driven.
Also:
1. Breathing out under water goes into about 0.4 PSI greater pressure than atmospheric. Therefore if you breathe "normally" like you would running, then you are exhaling (removing CO2) at a slightly slower rate. Compound to this the natural response to "hold breath" and you are building up CO2.
2. The body's trigger, sensory call to breathe, or the respiratory function is based on CO2 not O2. This has been called a glitch in the human programming.
3. Dehydration, (air travel, caffiene, soft drinks) amplify blood-gas(CO2/O2) related issues. So does the production of lactic acid for that matter.

Here's what I have done my past two swims anyway, but based on the above is really a must do:

Be very well hydrated at the start of the swim & no caffeine
15-20 minute full body warmup/workout to prime the arms, legs & core >> jog, TRX it or pushups etc. I think this is important to start lactic acid production & elevate CO2 responses as it is to kick start blood flow.
Be mindful of CO2 levels during the swim and exhaust CO2 harder - that is exhale more forcefully than "normal" atmospheric.

I think this can happen and has happened to perfectly healthy and well trained athletes, and will continue to do so unless education and protocols are put in place.

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There is still some question about my warm up. I did my usual warm up(bike and run) I normally will swim a little bit probably 300 yards. I don't call that swimming its mainly done to check goggles and get a feel for the temp of the water . I didn't get in the water because it was a little cooler than usual. Heat Wave is usually a really hot race. I went no wet suit and was fine in the water temp wise. I started pretty slow. I was shooting for a 17:00 to 18:00 swim (even flailing around I think it was 23:00 swim) I used to be faster but am still really comfortable in the water. My question about the swim is why wouldn't this have happened back in the day in Memphis swimming with Dick Fadgens Triathlete group. I used to max out all the time trying to get better with those guys. Coach Fadgen wasn't overly critical of my technique. The group he had swimming(Frank Rennelt-Renn Wheels,Corry Horton,Wendell and Pam RobertsonRichard Larrimore,Lucia Colbert) kept all of us motivated. If I was going anerobic all the time shouldn't something have showed up then?

Thank you for the detailed response to my question.

The first time wearing a wetsuit is uncomfortable. I've had similar experiences with a wetsuit.

Again, thank you and hope this never happens to you again.

Yup, I've found that spending time to make sure that the wetsuit is on properly and pulled up properly makes a big difference, especially with lower priced suits that aren't as stretchy. I need someone to give me a really good wedgie once they've helped me zip up, then I pull the front up,a lot. Plus I need the sleeves pulled up good.

I'll be using Ventolin at the start just in case so I doubt if this will happen.

But, being a "water baby", I don't have any issues with water, regardless of what it is like. Weeds, muddy, deep, it's all the same. Without a wetsuit a can "sorta" float on my back although my legs sink. With a wetsuit, no problem having a nap on my back :).

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BC Don
Pain is temporary, not giving it your all lasts all Winter.

I water-ski everyday with a multi-disciplined senior doctor at our hospital. We did discuss previously but I ran the specifics of my "diagnosis" (ie CO2 etc.) past him this morning. He added that elevated CO2 also causes vasodilation in the brain, which in the fixed volume on the skull increases pressure on the brain (swelling). When CO2 is high, the nervous system assumes O2 is low and the body shuts down blood to the limbs, diverting flow the brain. They use this feature in head trauma cases where they administer O2, to cause vasoconstriction & reduce pressure (swelling) on the brain.

So by letting CO2 levels get out of hand you are negatively affecting the brain - which can lead to confusion (bad decision making) and unconsciousness.


I asked him why this affects people mid 40's and up so much. He said there is so much more of a safety margin in younger bodies, circulatory systems etc. He said in young people it's hard to tell for example they are bleeding out until they outright lose conciousness. I totally feel this - I've lost my breath safety margin and training swim twice a day (1-2 hours per day since June) it is getting better but will take some time maybe another year, to learn how to ventilate with more efficiency.


Now about wetsuits. These damn tight wetsuits will encourage or help along the vasoconstriction of the limbs and add internal resistance that comes with moving in the paint-on suit, which will also produce more CO2! I had to upsize my Blue70 the first one I got was crazy tight in the arms and legs. (I have a M B70 fuzion for sale). I am in a ML Reaction now 170lbs 6'2". What I have been doing is using Armour All to lube the inside of the suit. In the race I lathered that stuff on like crazy, to reduce the internal resistance that comes from using the suit. It works great. You should use diver's lube though from McNett Corp.


My opinion is the w/s is safer that without, provided it is properly fitting and treated & fit to reduce the restrictive nature of it. With the understanding of the above, the last couple of days my breathing priority now is exhalation. So I focus on not how much air I take in but the timing and force of my exhale. When you swim hard you need to purge a lot of CO2! So at no time should the flow OUT of the lungs stop during swimming, unless you are on the intake.

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