If there’s one thing you know from doing jiu jitsu, it’s that you get sweaty. If you’re doing gi jiu jitsu, you get really sweaty. To perform well and recover fast, you need to put the water you lost back in. However, a lot of people think that if they just drink water, they’ve got it covered. Yes, drinking water is better than nothing. But do you really want to just be doing “better than nothing?” If you read my work on a regular basis (which is a very smart thing to do,) then you want more than that. You want to do your best. So how can you stay hydrated and rehydrate for the best results? First you’ll learn about what happens when you sweat, how thirst works, and how your body replenishes water. Then you’ll get the practical side on how to rehydrate properly. If you don’t care about all the why’s and science stuff, you can just skip the first section and go right to the practical end. If you all you want is the quick and dirty version, check out the video “Rehydration in 60 Seconds” above.

Why do we sweat? Well, the short answer is “so you don’t overheat like a car with a broken radiator.” When you exert yourself for an extended period, your body is breaking a lot of molecules for energy (mostly carbohydrate and some fat.) Kind of like your car’s engine, your body isn’t perfectly efficient at converting fuel into work. There’s wasted energy and that’s the heat you feel coming off the engine. Same goes for you. Heat starts building up in your body. The problem is that unlike your car’s engine, your body is very sensitive. If it gets above 104 degrees Fahrenheit (40 degrees Celsius,) you essentially end up cooking yourself and risk permanent damage and death. I might not be a black belt yet, but I’m fairly certain death would get in the way of getting an armbar. Luckily for you and me, evolution has given us a pretty cool solution: sweating. Your body’s thermostat will detect the increase in temperature and tell your skin to start sweating. Your skin is basically your body’s radiator, with sweat being the coolant.

So, does that mean you have water sacks in your skin and they just squirt it out like tiny bladders would squirt out pee? No, it’s not that simple. Remember how sweat is salty? Well, salt is the key to making sweat happen. In each sweat gland, there’s a lot of sodium.* If you remember high school biology (the class where they had you dissect a frog and had to fight the urge to make it dance and sing “Hello my baby, hello my honey,”) water goes from an area with low amounts of a substance to an area with lots of it. This is osmosis. Because your sweat glands have lots of sodium, water gets pulled into the sweat gland from the bloodstream. When your body gets too hot, the glands get squeezed and the water, along with some of the sodium, gets pumped out onto the surface of your skin. You are then soaking and taste like a pretzel. The heat from your body is used to evaporate the water, cooling you off.

You might be thinking that if you’re losing water, then the solution is to drink plain water. Unfortunately, that’s not good enough. The reason is that your body is very smart and very stupid at the same time. Your brain actually monitors how hydrated you are by watching your blood. If you’re dehydrated, two things will trigger your brain to make you thirsty: having less blood in your veins (low blood volume) and your blood being too “thick” (meaning it’s less like blood and more like honey due to lack of water.) When either or both of these things happens, your brain picks it up and makes you thirsty. This is why drinking water by itself isn’t good enough. You lose sodium and water when you sweat, but you lose more water. When you drink only water, you’ll bring the thickness of the blood back down. Your brain picks this up and tells you you’re not thirsty anymore, but total blood volume is still less than 100%. This means you’re still somewhat dehydrated. This is where salt comes in. By taking in salt with the water, you’re keeping the blood thick enough to set off the thirst signal, which makes you keep drinking water. You then get fully hydrated again and, if there’s too much salt, your body will just send it to the bladder.

Now I know what you’re thinking, “Wow, what a brilliant explanation of the elegance of our body’s cooling system, told with such wit. But how do I put all this into action to make me perform and recover better?” Well, observant yet pragmatic reader, grab a 32oz. (1L) bottle and follow this basic recipe:

• 32oz (1L) of water

• Heaping 1/4 teaspoon of salt

• 3 tablespoons of powdered drink mix (I like Tang because it really hides the salt well)

Combine all of these in your bottle, shake well (or drive over a bumpy road,) and you’re good to go. You might be wondering why the sugary drink is there. First, without it, you’re basically drinking seawater minus the fish pee. If you’re a masochist, go ahead and drink up. Personally, I have a hard time eating or drinking things that taste terrible. The sugar fixes that. Secondly, carbohydrate actually helps the body absorb both sodium and water. This is why when you do a weight cut, one of the things you do is stop eating carbs. Lastly, if you’ve got another training session that day, you’ll want to refill the stored sugars in your muscles (glycogen) so you can have the energy to go hard next time you train.

So, you just chug this down after you finish rolling and all will be well, right? Wrong. Don’t do that. Your belly will hate you and you won’t absorb it all. The most water your body can absorb in an hour is about one liter. So, how do you space this out? What I’ve found to work well is to drink one third of the drink ten minutes before class starts (assuming class is one hour.) For the practice portion of class, don’t drink. Then, just before and in between each round of rolling, take a couple swigs of the drink. When class is over, if there’s anything left, sip it and relax. From then on, plain water is fine.

So, there you go. You’ve got a recipe for rehydration and, if you read all the science stuff, a better understanding of how your body works when it comes to sweating, rehydration, and getting back to 100%. Yes, water alone is better than nothing. But if you take an extra 30 seconds, you can do a lot better. You put all that time and effort into your skill work and rolling, so why not make sure you’re in top shape while you do it? All that being said, if your training, diet, and sleep aren’t in order, then disregard this article and fix that first. If you’re underslept, undernourished, and weak, then a drink won’t make up for it. Don’t worry about the paint job if the car has no wheels.

*Throughout this article I’ll be using “salt” and “sodium” interchangeably. I know that they’re not the same thing. Salt is sodium chloride. Sodium is just sodium. However, for practical purposes, they are the same thing.

Disclaimer: If you’re diabetic, doing a weight cut, salt sensitive, or have any other serious restrictions/conditions, speak to your doctor and modify accordingly.