You’ve heard the phrase, “You are what you eat”. This implies that your diet has a transformational role in your health and physique. We could not agree more.

However, we have another phrase to live by; “Eat what you are!”. And by “eat”, we mean “drink”. Making up to 60% of your total body weight, there is no other compound more essential to the human body than H20. 

Found in virtually every single cell of the human body, water plays a critical role in all of your major physiological systems. This means the dehydration effects on endurance performance are massive and could cost you:

  • A podium spot
  • A successful training session
  • An ambulance ride to the hospital 

This is unfortunate as staying properly hydrated is relatively easy to do with just a little planning. That’s what this article will teach you.

Dehydration Vs. Hypohydration Vs. Euhydration

Let’s get some semantics out of the way. Dehydration and hypohydration are two related terms referring to the human body and lack of water. However, they actually refer to two distinct situations and yet are used interchangeably all the time. 

Dehydration is not inherently bad and refers to the general process of losing body water. This is a perpetual process that occurs at all times. This includes sweating, breathing, peeing and of course a bit of moisture from #2’s as well. On average, there is a turnover of 5-10% of your total body water every day. 

Under normal circumstances, water loss isn’t an issue as you are able to replenish it through hydration. This leaves you in a physiological state known as euhydration which is when your total body water is at normal levels. 

If you don’t replenish the water loss, your dehydration will continue until you reach a physiological state known as hypohydration. Hypohydration occurs when your total body weight has a sustained loss of at least 2% in weight due to water loss.

In effect, people are generally referring to what is more technically referred to as or the path to hypohydration when they say dehydration or “I’m dehydrated.” Regardless, due to the modern use of the term and the fact they are so closely related, we will use the term dehydration for the rest of this article.

If you want to be a real smarty pants in the face of your friends, enlighten them on the differences between dehydration and hypohydration.

Dehydration Effects On Endurance Performance

Due to various circumstances, water loss can sometimes not be sufficiently replenished. This can be the result of:
  • Extreme heat and humidity
  • High sweat rates 
  • Intense or prolonged exercise
  • Poor nutrition and/or hydration planning

None of this is good for athletes as the effects from becoming dehydrated can happen much quicker than once believed. 

Recent literature has found that when water loss reaches just a 1% decrease in body weight, a measurable decline in performance can begin to occur.  At this point, the impairment primarily impacts your cognitive ability such as making quick decisions; something that’s vital for MOTO, MTB and outdoor fitness  and athletes who have the added risk of being exposed to the outdoor elements during their activity.

If you continue down this path you will eventually hit a body water loss of 2%.  At this point, your performance will begin to deteriorate. You can expect to see:

  • 8.3% Loss of Muscular Endurance
  • 5.5% Loss of  Muscular Strength
  • 5.8% Loss of Anaerobic Power 
  • Higher RPE (Rate Of Perceived Exertion)

No athlete wants that, but outdoor athletes are even more susceptible to dehydration due to their protective gear. Wearing additional layers, helmets, heavy boots, armor, etc. causes the build-up of heat and raises the temperature of the body. In an attempt to cool off, the body will produce more sweat.

In addition, a rise in skin temperature has a direct correlation with decreased performance. At a ≥2% loss of body water, an athlete will experience an extra 1.0-1.5% loss in their performance for every +1 increase in skin temperature.

All these reasons are why it’s really important to understand your individual sweat rate during your activity of choice.

Determining Your Sweat Rate: How Much Water Do You Need To Drink? 

An effective hydration plan requires you to know your sweat rate. Measured in liters per hour or ounces per hour, your sweat rate is merely the amount you sweat in relation to time, environment conditions, equipment conditions and activity of choice.

For example, when riding in Arizona wearing full protective armor, our founder Mark found his estimated sweat rate to be 1-1.2L per hour. Keep in mind that depending on the conditions and activity, your sweat rate can fluctuate. Mark also noticed on cooler days, without armor, this number is substantially different. 

Now think about this, each liter of water weighs about 2.2lbs, that means that Mark would be into the extremely serious hypohydrated state in under two hours of ride time without replenishment. 

Instructions For Finding Your Sweat Rate

Before you measure your sweat rate, you need to be in an euhydrated state. The easiest way to identify this is using the WUT method which monitors the existence of 3 indicators of a state upon first waking:

  • Weight: Are you underweight?
  • Urine: Is your urine dark in color
  • Thirst: Are you thirsty?

The presence of one of these indicates you might be dehydrated; two indicates you’re likely dehydrated; all three indicate you’re very likely dehydrated. Once you’re in a state of euhydration, you’re ready to measure your sweat rate.

Finding your sweat rate is quite easy and you measure your bodyweight before and after a training session. To make the process easier, follow these tips:

  • Be sure to have a timer to time your session.
  • Weigh yourself before and after the training session in your underwear or even naked. Clothes will hold onto sweat and skew the weight.
  • Urinate before you weigh yourself. This is to mitigate the need to urinate during your training. If you urinate during the training session, you would technically need to collect it for your calculations of water loss.
  • You must also calculate any liquid you drink during the session. 
  • Using a shorter training duration (30-60 min) can mitigate the chance of needing to urinate during your session as well as the need to hydrate during the session.
  • Remember to wipe off all your sweat before your post weigh-in.
  • If you weigh in pounds, convert to grams.
  • Each gram lost = 1mL of water

You then relate your water loss to the time of your training. Remember to convert the time to hour. For example, if you lost 400ml in 30minutes, this would mean you’d lose 800ml in 60 minutes (1 hour).

Optimize Your Hydration With Fuel And Electrolytes

There are 2 other factors to consider when forming your hydration plan:

  • Electrolytes to prevent cramping and dizziness
  • Carbs for fuel


Our sweat contains a group of ion-containing minerals known as electrolytes. Within the body, electrolytes create an electrical gradient in extracellular fluid that allows electrical impulses to pass between your brain and muscles.

When you sweat too much, electrolytes are depleted and cause a disruption in the communication between your brain and muscles. Goodbye performance and hello cramps! 

In addition, electrolytes are needed to maintain your water-electrolyte balance. Solely drinking water to replace lost water dilutes the extracellular fluid resulting in a condition known as hyponatremia. Specifically caused by low levels of sodium, hyponatremia occurs much more frequently than once thought and can result in nausea, coma, and even death.

Carbs For Fuel

Glucose, by way of carb consumption, is the body's prefered source of energy. Unfortunately, your glucose stores (in the form of muscle and liver glycogen) are finite and can become depleted quite quickly during prolonged exercise. Prolonged glycogen depletion not only affects your muscles ability to perform, but it also leads to cognitive impairments referred to as brain fog. Luckily there’s an easy fix.

Simply adding a carb source to your hydration prevents this from occurring. The addition of carbs to an intra-endurance nutrition plan has been found to significantly improve athletic performance in countless studies. 

To ensure proper hydration with an appropriate amount of fuel and electrolytes, the easiest and most effective solution is to use a performance based hydration mix such as SUSTAIN. Just mix and you're ready to go with fuel and electrolytes coordinated to match your hydration planning!

Your New Hydration Plan

Traditional advice on hydration has been to drink when you feel thirsty. New research has uncovered a major flaw with this method as the sensation of thirst isn’t triggered until you’ve already reached a water body loss of 1-2%. In other words, “drinking when thirsty” is playing catch-up.

Instead, using your sweat rate, take calculated sips of hydration every 10-15 minutes. For example, let’s pretend Mark wants to know how much to drink. His sweat rate is 1 liter per hour and decides he wants to drink every 15 minutes. As 15 is ¼ of an hour, multiply 1 liter by ¼ and you get 0.250l (250 ml). 

Therefore, Mark should drink 250ml every 15 minutes to stay ahead of his hydration, which is more like a big gulp than a sip thanks to his heavy armor and Arizona temperatures. Accessibility of your fluids is key when you are sweating this much, this is why hydration packs are so key in dirt bike riding and why top pros route their tube directly into their helmets.

You can drink more often if desired (10 mins) but we do not recommend longer intervals (20 mins+)

Keep in mind that this is a base suggestion. Different individuals can burn more calories or even sweat more salt meaning you may need to adjust your hydration and electrolyte plan to match, but at least now you have a good starting point.


The most successful endurance athlete is the one who puts the same preparation into their nutrition and hydration as they do on physical strengths. Many times they are intrinsically linked! 

Staying as close as you can to an euhydrated state while you race is key for getting the most out of your training sessions, joy rides, and races. Knowing your sweat rate and using hydration planning with a fueling/electrolyte complex like SUSTAIN is a surefire way to check this box.

You can also look into pre-endurance training supplements that support hydration, fueling and focus like our PREPARE+ product. (It helps if they taste really good with natural flavors like ours do so you keep going back for more).


Explore our MOTO, MTB, and outdoor fitness pages to learn more. 2% of all our profits go to protecting trails, public lands, etc. so you can feel good about using Race Provisions products while you do what you love. 

If you have questions on your personalized nutrition plan or any of our products, be sure to Contact Us! Simple performance nutrition is what we do! 

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