Wednesday, May 30, 2007

SIPE

A couple of weeks ago, I had a swim lesson at Aquatic Park, which is a swimming area in the San Francisco Bay. It was a warm sunny day, but the water was still cold. After warming up for a few minutes, we started with some intervals to practice open water pacing. After a fast interval lasting several minutes, I brought the intensity down to an easy level. Normally, I would start to recover right away after backing off on the pace; this time, I was struggling to get my breath back. I swam for several minutes more and did not improve. By the time the set was over, I could not swim another stroke.

Once I got out of the water, I started coughing profusely and spitting up slightly pinkish froth (sorry, a little gross). I definitely had fluid in my lungs, and felt severely short of breath. I could still walk and talk, and didn't feel like I was in any imminent danger, but the coughing did not let up; nor did the frothy spit. Weird! I had to go back to work after my lesson and continued to cough and feel very tired.

After doing some research, I identified the event as an episode of swimming-induced pulmonary edema, or SIPE, which has been infrequently reported in medical journals. My symptoms fit exactly with other described cases. Conditions which lead to SIPE have been described as cold, open water swimming or diving at high intensities. The thought is that the cold water in addition to the position of the body during swimming causes central pooling of blood; during intense swimming the pressure in the pulmonary capillaries becomes too great and fluid and some red blood cells (along with some other large proteins) break through to enter the alveolar sacs in the lung. Where there is water, no air will be exchanged so this is not a good state to be in!

I actually contacted the authors of one of the papers and we may work together to collect some more data on this condition, especially in triathletes. If it becomes severe enough, it can be fatal through drowning. I was surprised that no one in the triathlon community (with whom I have spoken) has ever heard of this, especially considering that we all swim in very cold water frequently, and may often try to swim fast. (Cold water and intense swimming are typical contributing factors.)

Fortunately, the condition seems to resolve within a week, and some careful physiological tests done in one study show that within a month, it is impossible to distinguish those who had it from those who didn't. I felt mostly better the next morning and completely better by the day after. I've been able to complete further swim workouts without any problems like that; although I still need to get back in the Bay to see how that goes. Fortunately, I won't be swimming as hard as I was in Coeur d'Alene, and the lake water temperature there is warmer than at Aquatic Park.

4 comments:

Shannon said...

Go to the forums, and then click on triathlon talk on beginnertriathlete.com and ask if anyone has experienced the symptoms you had.

You'll have to sign up for a free membership to post, but the members there are really good about replying. You might get some people who've had those symptoms.

Bernard said...

Well that just sounds awful. I'm glad you don't seem to have had any longer term issues.

Maybe I'll use this as my excuse for not swimming with the kids in future!

If you're going to experiment, make sure there's someone watching over you. And I don't just mean Him.

James said...

I completed the Centurions Alcatraz swim with the Water World folks yesterday and experienced exactly the same symptoms and consequences. I have been swimming 1.75 miles several times a week, including open water swimming in the Monterey Bay.

My thought is that a couple of things worked together to produce this (I really struggled and finished the swim doing breaststroke and feeling like I was really pathetic):

1. The jump put me in the middle of about 400 swimmers and many went over the top of me, something I was not prepared for. One of the journal articles I read said that the further the chest sinks in the water and the more vertical, the worse the effect.

2. I was swimming far more intensely than normal. We had been told to get away from the boat and the island ASAP...and I swam like the dickens for about 20 minutes...

3. The water temperature pushed my blood to the interior organs, particularly the lungs, normal under hypothermic conditions, though the temp was really warm at about 64 degrees...I train in about 59 degrees

I finished feeling very bad and the first aid people had already left. My family bought me a cup of ocffee, thinking that the diuertic would help with blood vessel dilation. This was exactly right and I began to feel better right away. Still weak, I walked the several blocks back to my hotel.

I really felt like a failure having to limp in, but realizing now that this is a condition that occurs and probably more frequently than one would imagine. I would be interested in providing data or helping in any way possible with ongoing research. I am a PhD from a small teaching university, so I do understand the need for more research on something like this.

The bottom line, thankfully, is that I made it in, I am much, much better now and plan to do this again next year with some better planning (I had had someone warn me about the chaos at the jump...should have paid closer attention!)

Anne said...

Hi James,
Thanks for posting your comments. There is a small group of us now interested in this problem, and slowly formulating some plan to investigate it. If you would like to be involved, drop me an email at
sf_runnergirl at hotmail . com

I'm very glad you made it through okay. It was a very disturbing experience for me when it happened; although I was also much improved within a day or two. Since then, I have not had this problem in open water, even during a pretty intense IM swim, but I also have kept the intensity at a more moderate pace.

Thanks,
Anne