Early Cold Water Acclimatization

After Malta, the focus of this springs training shifted from endurance training to cold water acclimatization.   I planned on taking a mental breather from the long workouts after Malta but I quickly realized I had a relatively short spring season of cold water to use for cold water training before the local lakes warmed up.  From information I had received from the fellow channel swimmers at Malta and followup reading, every season that you do cold water training will make it easier.  I did not want to miss this spring season. 

Shortly after returning from Malta, I caught a "travel cold".  One of those colds that come from sitting on a cramped airplane with limited airflow combined with jetlag lack of sleep.  I was reasonably incapacitated for nearly a week after my return.  Finally, on Saturday I felt good enough to swim again.  Eliz and I headed for a local lake.  I measured 55F (12.5C) in the lake with an air temperature of 42F (5.5C).  It was a bit cooler then the 59F (15C) of Malta.  We hit the water for 30+ minutes.  It felt cold but doable.  We both felt we could have gone a little longer but thought that it was best to work into the colder water swimming slowly.  

The next Thursday, we hit the lake again with a goal to try for an hour.  The temperature was again 55F (12.5C).  We crossed longways across the lake (0.9miles) and back.  When we got back, we checked with each other to see how we felt.  The water felt cold but we both felt our core temperature was still ok.  We headed out along the shore line for a quick out and back to make it to a hour.  As we returned, we did start feeling some of the effects of hypothermia.  In particular, both of us hands started forming the "channel claw", a relatively common cold water long distance swimming occurance.  As the blood flow continues to be limited to the hands plus the drop in temperature in them, the muscles control drops such that the fingers start separating and bending in a manner that looks like your hand is clawing something.  We tried to control the muscles to hold the fingers straight but it was not working.  We finished the swim in slightly over an hour and headed to warm clothes.  I had a solid 40 minutes of shivering but became useful around the house within 75 minutes.  Not bad for our first hour swim at 55F (12.5C).

This morning (Cinco De Mayo), we hit the lake for a third time since Malta.  Since last Thursday, we have had a cold spell with a significant amount of cold rain(as in it was snowing in slightly higher elevations).  The water temperature had dropped to 53F (11.5C).  With the colder water, we decided that the goal would not be to go longer then last time but try to hold the same time.  Also with the colder water, we stayed a little closer to the shore in case we had problems.  We headed out on a course that was about 15 minutes out and then back.  The water definately felt colder but after about 5 minutes, the body seemed to be settling into a comfortable middle ground where we could feel the cold water but the core temperature seemed to be ok.  It ended up being a beautiful morning with the sun rising over the horizon while we were swimming with mirror smooth water.  I finally had some significant time just zoning out and enjoying.  I had not had that feeling yet while swimming in cold water.  It felt great!  After one 30 minute lap, we checked in with each other to make sure we felt ok and headed out for a second lap.  Shortly after we turned around, I started feeling the channel claw forming.  It felt as if I could not grab any water.  I was afraid I was going to slow down so I tried picking up the cadence.   I felt I was holding a reasonable speed but I kept seeing Eliz pull ahead and then slow down.  I was not sure if I was slowing down or if she was speeding up.  With about 100 yards to go, I saw her hesitate for second and then continue to the end.  As we got out, she asked if I felt ok.  I replied that I did but explained my claw issues.  She mentioned that in the last 5 minutes I had slowed down significantly and she was starting to get nervous.  The hesitation I saw was when she thought for a second about stopping me and asking but then realized it would be quicker just to finish the swim and then ask.  She checked my skin color and it was still a healthy pink.  We did not make our full hour, only about 55 minutes but Eliz was nervous enough not try to push to an hour.

This reaction does confuse me.  Obviously I was having some early signs of hypothermia.  The confusing part is I definately felt colder in Malta without the channel claw problems and slowdown.  Also, my recovery from the swim was one of my quickest one.  I had only medium shivers that lasted less then 30 minutes.  This seems to indicate my core temperature did not drop as much as previous swims.  However, I was experience more significant hypothermia issues with the channel claw and the slow down.  At this stage, I am guessing that the core is adapting quicker then the extremities to the cold water which would not be a big surprise.  From discussions with fellow channel swimmers, these symptoms will come later and later in the swim to the point they will not show up in normal training.  I just need to be patient and keep the cold water training up.