I'm Thirsty

The past few weeks, I have heard way too many people say it is too hot to exercise outside. Even if it is just a half hour walk, my mom is the first person to use the high heat and humidity that has been engulfing our summer air here in New Jersey to stay inside and watch Dr. Oz (we already know how I feel about that). My cousins and I are the first generation to be born here in America, so for my family (native to the scorching hot Dominican Republic) to say it is too hot to go outside is just ludicrous. So why the excuse? Why the sudden need to use bearable weather (at least for our family) as means to stay inside? Obviously a lot of factors go into this. Laziness is one of them, but again, I already wrote about that. Another factor is the sports drinks industry, and here's why.

For the past 20(ish?) years (I don't know exactly, I'm only 19), the sports drinks industry has been marketing that humans need to say "ahead of the thirst" to be properly hydrated during exercise. Really, they just want you to drink their product before, during, and after your exercise. You need to be putting electrolytes back in your body and giving yourself the proper hydration because you "lose" so much of it with sweat that it could be potentially dangerous! (Please reread that sentence with a bit of sarcastic humor in your voice.) I'm going to bring up a newly published article at bmj.com (literally published like, today). Written by the awesome Timothy David Noates, this article brings up how and why being overly hydrated is more dangerous than being dehydrated. I bet you didn't see that one coming.

Let's start with dehydration. When does dehydration become a serious health risk? Well, once the total body water content drops 15% or more is when. How much time does it take for your body to decrease in 15% of its total body water content? Well, it actually only takes 48 hours in a desert with absolutely no water! So now you might be asking why is it that many distance runners and athletes collapse when it is just "too hot" outside to be exercising? Here's the common misconception. Because of marketing of sports drinks, many think that dehydration is the cause of an athletes' collapse but, that usually isn't the case. Commonly, a collapse due to exercising in the heat is because of exercise-associated postural hypotension, or low blood pressure due to exercise. That, my friends, has very little or just about nothing to do with hydration.

Now we can go on to hyperhydration, or water intoxication. An increase in total body water by just 2% can lead to serious health risks like edema (when there's excess water in cavities and tissues of your body). A greater increase can cause hyponatremic encephalopathy, a really scientific way to say cerebral edema, or excess water in your brain. If untreated, this can cause death by respiratory arrest. Less severe (but still pretty severe) health conditions also caused by hyponatremic encephalopathy can be confusion, seizures, and coma. 

The truth is, humans have evolved to regulate their body temperatures during long bouts of exercise in dry heat (how do you think our ancestors hunted?). We don't need to replenish and regulate our fluid balances during exercise at all really. When you feel thirsty, it's because you probably broke a sweat (yay, you burned some calories! CONGRATULATIONS!) but it is no need to drink something. At least, not yet.

What I really wanted to say, was that when it is really hot outside, you can still go out and run/jog/walk/ whatever in this heat. You won't faint from dehydration. You might sweat a lot, but all of that water loss can be replenished at your next meal. Don't fear the heat, embrace it! And if you do feel dizzy or nauseous, lay on your back with your feet higher than your head!

T.D. Noakes Article