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Hydration for Motocross

by Clint Friesen


As the mercury rises, proper hydration both on race day and during training sessions becomes increasingly important for peak athletic performance. Most riders understand the need to drink lots of water but less understand the importance and role electrolytes play in hydration. The following is a set of guidelines I’ve put together throughout my years of training MX and SX athletes in the hot and humid environment of the southern states.

Most people are familiar with the term electrolyte and understand that it is part of the hydration conversation. Some may even be able to name a few like sodium (aka salt) and potassium. But that is typically where the understanding ends and most athletes fail to understand which electrolytes are most important and why they need them. Electrolytes are important for energy production, nerve transmission, muscle contractions, pH control, and fluid balance to name a few.


Typical Daily intake (mg)

Typical absorption efficiency Typical sweat loss/litre Loss in litres of sweat to deficient Deficiency possible by sweating
Sodium 4,000 >90% 230-1,700 4 Yes
Potassium 2,700 >90% 150 16 No
Calcium 500 30% 28 5 Possible
Magnesium 300 10-70% 8.3-14.2 15 No

Overview of the most important electrolytes

To further illustrate the importance of electrolytes, let's take a look at a common symptom of dehydration; cramping. Most riders panic when they get cramps and their first reaction is to begin drinking tons of water in hopes of rehydrating quickly. If the cramps are caused by water loss from sweating this method may in fact reduce the cramps. However, if the cramps are from a lack of electrolytes then the problem will only get worse. Introducing more water into the body will actually dilute the amount of electrolytes available making the cramps even worse. So from this simple example you can begin to see why it is important to have at least a basic understanding of electrolytes and hydration.

Managing sweat volume and sweat sodium concentration are the two main factors of proper hydration.

It’s been my experience that most riders will cramp due to 3 things.

  1. Water - specifically not enough water (dehydration)
  2. Salt - (sodium to be precise) which can be lost in huge amounts through sweating
  3. Magnesium - similar to sodium, this is another electrolyte that is important for the muscles to function properly.

Our sweat is a mixture of water and sodium mainly. Sometimes after a long workout may notice a white film on your clothes which is mostly sodium that was left behind after the sweat evaporated. The biggest difference from one athlete to the next is the amount of water they lose and the concentration of sodium in that water. In terms of sodium loss (the ‘most active’ and important electrolyte lost in human sweat) studies have shown some athletes can lose as little as 2,300 mg of sodium while others shed as much as 30,000 mg of sodium in exactly the same training session! Managing sweat volume (the amount of water lost through sweat during exercise) and sweat sodium concentration are the two main factors of proper hydration.

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For a little more detail let’s cover the technical terms. Sweat rate or the amount of water lost through sweating will vary for each individual. You’ll notice that some people seem to sweat gallons and some don’t sweat much at all. Based upon your current physical level, where you’ve been training (i.e. Alaska vs Florida), genetic factors, etc., everybody is going to be a little different. The other term we often discuss with our athletes is sweat sodium concentration. This is the amount of sodium that is lost in sweat, drop vs. drop. For example, one guy might lose 1 mg of sodium per drop, while the next person loses 2 mg of sodium per drop. The typical range of sweat sodium loss can vary from 1,000 mg per gallon all the way up to 6,000 mg per gallon.

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It is important to note that a normal IV solution administered by a medical professional contains approximately 3,500 mg of sodium per liter. We’ve all seen the situation after a race where an athlete is down and they come to his rescue with an IV. Reason being, the IV solution is able to reload the body with water and sodium quicker since it bypasses the stomach and goes straight into the bloodstream. The issue with trying to drink that amount of sodium infused water is most people would not be able to tolerate that on their stomach. For that reason we try to stay below 1,000 mg of sodium per 20 oz. glass of water to avoid stomach issues. Staying on top of and understanding your individual sweat rate and sweat sodium concentration is key to staying ahead of your hydration needs throughout the day. Once you start falling behind it becomes increasingly difficult to catch up. Especially during long motos.

As we have discussed, each athlete will need to hydrate differently based upon the concentration of sodium and the amount of sweat they lose. The real trick is to know how you can measure these two variables.

Sweat Loss: The easiest method to determine sweat loss is to weigh yourself both before and after training. This is most accurately done with no clothes on before and after the session. Then drink 16-20 Oz of water for every pound of weight lost during exercise. An average sized water bottle is typically 16 Oz and 16 Oz equals 1 pound. So if you lost 3 lb. during your exercise or riding session you would need to drink 3, 16 Oz bottles of water to replenish what was lost.

With motocross, it can be difficult to weigh yourself before and after riding since so much riding gear is involved. Don't make the mistake of putting all your gear on, weighing yourself before you ride and then doing the same thing after you ride. The sweat you lost is absorbed by your gear so getting an accurate weight is impossible. The only way to do this accurately is to weigh yourself before riding (no riding gear) and then after (no riding gear). This can be a tedious process and most riders will just opt not to do it. But if you can be disciplined enough to do this a few times, soon you will begin to figure out how much water you need on hot days vs cold. Here’s another tip that might help.

Use a gallon sized container so it’s easy to judge how much you’ve consumed throughout the day. Lots of athletes forget exactly how many bottles of water they’ve had throughout the day so one large container is easier to track. Plus if you know you need 1 gallon total on the average day of training and it’s halfway through the day, you should be half done with the bottle. It’s a great visual tool.

Weighing before and after (without your sweat soaked clothes on) is going to show you how good or bad you estimated your hydration needs. If you weighed 150 lb. at the beginning of the day (before riding) and 149 at the end of the day (after riding), I’d say you did a pretty good job. If you were off by 5 lb. or more, then that’s a major issue. Forget cramping, performance is going to be affected way before you start to cramp. Try to drink more water the next day, then compare your before and after weights to see if you did a better job at maintaining 150 lb.

Sweat Sodium Concentration: Calculating sweat sodium concentration is a bit trickier. Here are a few tips that will help you figure out if you’re high, medium, or low on the scale.

  1. Do you cramp - a lot, sometimes, or never?
  2. How would you classify your sweat rate - High, medium, or low?
  3. Do you see a salt residue on your skin or clothing after exercise - always, sometimes, or never?

If you cramp often, sweat a lot, and can see salt on your clothing after training then odds are you have a high sweat sodium concentration. Athletes in this range need to be closer to the 6,000 mg per gallon range on salt. If you seem to be answering no to most of these questions then I would stay conservative on the salt intake and lean towards the 1,000 - 3,000 mg range.

Unfortunately there is no single answer for how every individual should hydrate. However, the guidelines we covered should help you in making the correct decisions to meet your own personal needs. Try not to complicate things and focus on the two main factors (sodium and water). If you can keep those in balance throughout the day you should be just fine. Check out myh2pro to see how we sweat test our athletes. Or visit Skratch Labs and look at their Hyper Hydration Mix. Many pro athletes like to use this formula in high heat and humidity situations. There are many products on the market but Hyper hydration along with H2Pro Hydrate 1500 are the strongest electrolyte mixtures I’ve been able to use successfully with my athletes.

About the Author: Professional trainer Clint Friesen has been in the motocross scene his entire life. He grew up racing and riding and eventually ended up studying sports medicine and exercise science at Florida State University. Clint specializes in using Near Infrared Spectroscopy and is a part of the MOXY Monitor development team. Clint helps guide many NFL, NBA, Olympic, and Division 1 Collegiate programs in testing and training their athletes. He also works closely with Per Lundstam and the RedBull High Performance Department. Owning and operating his own lab out of Destin Florida, Clint has remained close to the sport and continues to work with riders like Joey Savatgy. Over the last decade he’s trained many athletes including; Gavin Faith, Jordon Smith, Anthony Rodriguez, Paul Coates, Dakota Alix, Justin Barcia, Keith Tucker, Martin Davalos, and dozens more. Any questions or positive comments can be directed my email:

That's it for now, until next time, good luck with your training and remember, if you have a question, log on to the Virtual Trainer Expert Forum and have your question answered by a panel of experts. In addition, be sure and check out the Racer X Virtual Trainer archive section. Your complete one-stop information zone for motocross fitness. VT Signature

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  1. Gravatar
    SImon June 13, 2014 at 8:33 am

    Cool article. Thanks! So what about the commercially available sports drinks like Gatorade etc. Worth drinking? Or just a load of marketing rubbish?

  2. Gravatar
    Joe June 13, 2014 at 11:05 am

    Simon, it looks like the usual sports drinks are fairly low on the sodium scale when looking at the back of a bottle.

  3. Gravatar
    Clint Friesen June 13, 2014 at 2:33 pm

    Joe nailed it on the answer. They are pretty low on the scale. I'd imagine those big companies are trying to create a product that everybody can use in order to reach the masses. However, the whole point of the article is to illustrate how everybody is unique in terms of sweat and hydration levels. No single product can meet those demands.

    Another issue to consider is the amount of product (in the commercial sports drinks simon referred to) you would need to consume in order to meet your sodium intake needs. How much sugar would you be consuming in the process? Key words here: Insulin control, blood glucose levels... There is a balance between too much or not enough when it comes to blood sugar levels. To meet your body's demand for sodium, could you potentially be going overboard with sugar if you're using purely sports drinks to get your sodium??

  4. Gravatar
    kmiracle June 13, 2014 at 6:04 pm

    This is an issue i personally have... I hardly sweat and then overheat easily. When we get off the trail, my friends are drenched and i barely look like i've sweat at all. i drink water all the time and i think there must be something wrong with me. i've thought i should go to the doctor about it, but never have. not really sure what they'd do... any thoughts?

  5. Gravatar
    Racer X Virtual Trainer June 16, 2014 at 7:43 am

    Kmiracle - Unfortunately, I do not think there is anything a doctor can do for you. BUT I'd go see my family doc anyway just so he can do blood tests, etc. to make sure there isn't anything else going on. Perhaps you are not as hydrated as you think. Blood work will show this.

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