Wednesday, August 11, 2010

Water, Dehydration, And The Long Run

Sunday's run was over the 22 mile long T-888.  The day was hot, which seems to be a common theme for the past few weeks.  But somehow, this day was different.  the air seemed sharper, harsher, as if it were saying, "come on out here pal.  I'm gonna work you today".

And it did.

One of the challenges was that I went running just before high noon, which turned out to be a mistake. The other challenge was that the air was dryer than it has been over the past few months.

Typically, my shirt would be soaked within the first 10 minutes of the run and my feet would be swimming in my sweat filled shoes by the end of the run.  The humidity has been such that water evaporation off of the skin was tough, a blessing and a curse.  If your sweat can't evaporate, the body has a more difficult time cooling down your core temperature.  However, on the flip side, water reclamation is as simple as licking your lips!

But not today.  The air was a lot dryer than it has recently been.  That coupled with the high noon heat and direct sun meant that my skin was being turned into leather with every step I took.

This day was a challenge in water management.  Because of the dyer air, I lost a lot more water than usual.  Typically, I can run the first loop of the T-888 and have just under 20 ounces of water left by the time I hit the water bubbler in the park.  Today, there was none.  I had drained both bottles and still felt thirsty by the time I hit the bubbler.  That should have been a sign to quit while I was ahead.

But I figured that if I slowed up the pace interspersed with some walking, I should be able to get through the second loop on two 20 ounce bottles.  So I continued onward.

Like I said, big mistake.

In spite of slowing the pace down and walking a bit on the second loop, I had less than a quarter of a bottle left, or just 5 ounces of water, with 5 miles left to go.  A very thirsty 5 miles to run.

Typically I do the T-888 consuming a little over a gallon of water. Today, it was more like 3 gallons and that still wasn't enough.  And my clothes were completely dry when I finished. 

Lesson learned during this run dealt with water management.  Naturally, there are conditions that I can control which will impact how much water I consume, such as the intensity of the run or the type and amount of material worn during the run.  Even eating can have a major impact on water consumption.  Digestion is a water intensive process.  But there are other conditions that I can't control like temperature, weather, and now humidity.  Big factors to consider on race day.

I'm not sure  which is worse, high humidity where the sweat can't evaporate to cool your core temperature, or low humidity where you can quickly and easily lose your bodily fluids.  One thing is certain, a combination of high temp and low humidity isn't a lot of fun.  Let's see, we are gonna take away all of your fluids until you can't sweat anymore and your blood thickens up, and we are gonna heat up your outside skin temperature until it's higher than your internal body temperature.  Stick me in the microwave and cook me like a Thanksgiving turkey!

This run was also about reconnecting with prior experiences, like realizing that dehydration can lead to muscle soreness, muscle cramps, loss of performance, fatigue, disorientation, and in extreme cases, heat stroke, brain damage and death.  This should have been an easy realization given how much time I've spent hiking in the great southwestern desert.  But I think I've spent too much time around green trees and in big cities you're only as thirsty as the nearest lawn sprinkler.

Might be time for another desert excursion!

4 hours of running in the Asics Gel 1130s.

No comments:

Post a Comment