I sweat. A LOT. Like, more than the average bear. You come out of spin class looking like that? I come out of Biology class looking like that in the summertime. It’s true. Ask Tweedy. I can’t help it. I come from a long line of sweaters and am happy to say I am not the only one in my family whose internal A/C goes into overdrive at the mere sight of the sun or a humid day or a flight of stairs. I am my father’s daughter in this way. Mrs. Obi-wan hardly every breaks a sweat. She glooooows.

What does this have to do with hydration?

I’m getting there.

Because I sweat a lot, I lose a lot of sodium as well. Sweat is not just water, people. It is a combination of water and sodium and other trace minerals. You can feel the salt if you let the sweat evaporate on your skin and don’t wash it away. If you reeeeally get your sweat on and it dries a little bit, you can see it on your clothes, too! (Wait, is that just me? Someone tell me it’s happened to them, too!)

Exhibit A The salt all over my face post-marathon:

The salt is everywhere, as is the hair.

So what does this have to do with hydration?

I’m getting there.

Because when you sweat you lose sodium and other minerals as well, you must replace those minerals in order to rehydrate. You’ve heard me say that water just isn’t enough for endurance sports and it isn’t because of this reason. When you lose too much sodium and the sodium-potassium-calcium balance is off in your blood plasma, bad things happen. If there isn’t just the right amount of sodium and the right amount of potassium to work the sodium-potassium pump, bad things like dehydration and over hydration (hyponatremia) happen.

Dehydration gets a lot of media attention, but I want to focus on balance and how not to overdo it on race day.

One of the very helpful things that happens when you’re nervous on race day is dry mouth. You’re at the start line or just barely getting going and you swear your mouth is as dry as the Sahara. Please, please, please read this next line and tell yourself this: You are not thirsty. You have dry mouth. Swirl and spit. It will pass.

If you chug a cup of water or Gatorade every time your mouth goes dry during a race, you are putting yourself at risk of over hydration (hyponatremia) which is just as dangerous as dehydration. Trust me, I learned this the hard way. My first marathon (NYC) was 80-something degrees in November and I panicked throughout the entire run. I drank WAY more than I ever did during my training runs and ended up with a sloshy tummy full of fluid, which I promptly vomited at the finish line and again in the shower, and I experienced some serious disorientation and weakness immediately upon finishing. It wasn’t pretty. Ask Mrs. Obi-wan and Kooshie. I will never forget them taking care of me.

The way to avoid this is to test yourself during your training runs and make a mental note of when you usually drink, how much you drink and what you like to drink. I carry Gatorade with me and drink water at water stations when I want only water. That way, I always have something with a little sugar, carbs, sodium and potassium with me in case I need them. Be wary of the coconut water craze. Not every brand is all it’s cracked up to be. I also always have a Shot Bloks for sustenance, but Rice Krispie treats are yummy, too.

Trust your training and do not detour from it. Don’t like what they’re serving at the hydration stations? Carry your own. Not sure if you’re thirsty or just have dry mouth? Swirl with some water and spit and see how you feel in another quarter mile. Worried because it’s hotter than usual? Hydrate throughout the race by taking small sips, not big gulps. Wondering how your hydration plan is going? Check your forehead to see if you’re still sweating. Sweat? Good! No sweat? No good.

If you fear that you are suffering from dehydration or over hydration, seek medical attention immediately. Dizziness, loss of consciousness (even for a moment), disorientation, loss of coordination, vomiting, and lack of sweat are all bad things and you should get yourself to a medic as soon as possible.

Test your hydration strategies on a day other than race day and you’ll be a hydration rock star during your race! This goes for all sports: cycling, spinning, yoga, swimming, rowing, everything where you’re breaking a sweat for longer than 30 minutes (for me, it means all damn day). I don’t want to hear that any of you passed out because you didn’t hydrate properly, ok? Ok.

Now go out and run!