Sweat! Let's talk about sweat.

Got out this morning in what I called "Marshmallow Fumidity" it was so humid. No sun could penetrate this thick cloud of yuckiness. This was good, though! I wanted these conditions (75 degrees, 81% humidity) because this was the morning to test out how much I sweat in these conditions. I ran 6.67 miles in exactly 1 hour for a 9 min/mile flat pace, which is my base.

Here is the formula that I learned when I wrote my Beating the Heat, My Plan post. I didn't eat or drink anything during the run and didn't use the bathroom after or before the measurements. What is lost is purely through sweat, tears, and thermal energy.

Starting Weight	154.5
Finishing Weight	151
Total Loss	3.5
Calories Burned	667	(I burn roughly 100/mile)
Calories in Weight	0.2
Total Sweat Loss	3.3
Sweat in ounces	52.8
Ounces lost per mile	8
1 Liter of liquid	33.8	Ounces
My loss in Liters	1.56

Isn't this convenient!!! So had I known my sweat rate, and if I had a race today in these conditions, I would need to drink 1 cup of liquid per mile to keep my body @ a constant hydrated level, roughly. Fortunately NYRR races in the summer have water stations @ every mile.

But it all makes sense now! I was doing just that (drinking ~8 oz every mile) in New Orleans in April and ran a 1:56:xx Half Marathon in my second Half Ironman, which I still consider a VERY successful run.

What you sweat out of your pours is not just stinky H2O. You are also losing electrolytes (sodium & potassium). I had salt stains on my tri suit yesterday from the 3 hour ride in the heat. How much sodium was that and notice that I used both salt and sodium in the same sentence? Salt and sodium are two different things that both share sodium. Salt is sodium chloride, sodium is just sodium. Its not like you have table salt running through your veins. Table salt is just a crystalized form of sodium with about 100 other minerals involved, primarily chloride.

According to all of the articles on the trustworthy inter-webz, a normal average person can sweat out ~1000mg of sodium per liter of sweat lost. So for me, @ ~1.5 liters of sweat lost per hour while running, I could be losing ~1,500mg of sodium. Other than feeling tired and thirsty, I noticed no muscle cramping, but then again I was only out there for an hour. Tack on another hour, and I'd prolly bonk from lack of nutrition before the lack of electrolytes got me. I have never had an issue with cramping (knock on wood) and for the Half Ironman distance, I have raced them both hot and cool, and have never had issues other than not consuming enough calories.

I guess what I am going to take from this test is that I now know how much I need to drink per mile on the run in hot conditions to stay hydrated and to keep my core cool(er). I remember hearing a pro triathlete talk about how he keeps his core temp down on the run in the heat, and that is through the ingestion of cool liquids. Yes, dumping water over your head helps, but its only a temporary solution. Ever see them handing out ice @ aid stations? Call that your best friend and chomp that stuff down and wait a few mins. I did this down in New Orleans and I kept coming back to life over and over again.