In This Article You’ll Learn

• The difference between hydration and fueling
• Why water alone isn’t enough
• What electrolytes actually do
• Signs you’re drinking too much or too little
• How to build a simple hydration plan

There I was flying down Whitetop Mountain, chasing what I hoped would be a personal best in the 50-mile distance. The course was perfect—a long gradual descent before flattening out for the run to the finish. It was about 50 degrees, I was sipping water consistently, and everything felt under control.

Then my calf cramped.

My stomach started feeling off.

I did a quick self-check. I had been drinking plenty of water, so what was going on? Then it hit me. I had left my salt pills back at the hotel that morning. It wasn’t water I was missing. My body needed electrolytes.

What does hydration actually mean? It is simply put the process of absorbing or maintaining an adequate amount of water in the body to keep it functioning properly. Water makes up 60% of the body. It supports systems in your body that regulate temperature, lubricate joints and move nutrients through the blood.

Electrolytes are minerals like sodium, potassium, magnesium, and calcium that help regulate fluid balance, muscle contractions, and nerve function. When you sweat for hours on the trail, you lose both water and electrolytes—and both need to be replaced.

During long, intense efforts like trail races and ultramarathons, you need to replace both the water and the electrolytes you lose through sweat. If you don’t replace enough fluids and electrolytes during long runs, you may experience symptoms such as:

• Dry mouth
• Muscle cramps
• Severe fatigue
• Dizziness
• Nausea

On the other hand, drinking excessive amounts of plain water without enough sodium can also cause problems. In severe cases, it can contribute to a dangerous condition called hyponatremia.

Signs of Dehydration vs. Overhydration

Dehydration	Overhydration
Dry mouth	Bloated stomach
Thirst	Swollen fingers
Dark urine	Sloshing stomach
Fatigue	Nausea
Muscle cramps	Headache
Dizziness	Confusion

This is why every long run is a chance to practice. Experiment with different hydration products and different amounts. What works for me may not work for you.

Pay attention to how your body responds. Cramping that seems to come out of nowhere, bloating, swelling, dizziness, or unusual fatigue can all be signs that your hydration strategy needs adjusting. Take notes after each long run and share them with your coach if you have one.

My personal hydration plan is sipping water continuously through the run and using a sports drink to supplement the electrolytes. Personally I use Formula 369 but I am also capable of using Tailwind, Gatorade and Skratch because I have tested those out during long runs as well. You always want to be able to pivot to what the race is supplying if you can. If it’s hot I bring more water as well as increase my sodium intake. If it’s colder I won’t drink as much water but I will continue to use 369 the same way. I will also carry salt pills as a backup plan since they are easy to carry and don’t require mixing anything.

My Hydration Plan

✔ Sip water consistently

✔ Formula 369 as my primary fuel

✔ Salt pills as backup

✔ Increase sodium in hot weather

✔ Drink less in cool weather—but maintain electrolyte intake

One of the biggest mistakes new trail runners make is treating hydration and fueling as the same thing. Sometimes your drink provides both. Sometimes it doesn’t. Know what you’re actually putting into your bottles. Read the nutrition label before race day so you know exactly how many grams of carbohydrates and how much sodium you’re getting in each serving.

The most common mistakes I see athletes make:

• Drinking only when thirsty
• Drinking every chance you get
• Ignoring sodium
• Never practicing hydration
• Assuming one plan works for every race
• Trying to “catch up” after falling behind

Final Thoughts

Hydration isn’t something you figure out on race day.

It’s something you practice every long run.

Experiment.

Take notes.

Adjust.

Repeat.

By the time you reach your goal race, your hydration plan should feel just as familiar as your running shoes.

Hydration Checklist

☐ Fill bottles or hydration vest

☐ Know how much sodium your fuel provides

☐ Carry backup electrolytes

☐ Practice your hydration strategy

☐ Adjust for the weather

☐ Never try a new hydration product on race day

Trail Nutrition Series

• How Many Carbs Do You Need During a Trail Race?
• How Often Should You Eat During a Trail Race?
• What Should You Eat Before a Trail Race?
• Best Foods During an Ultra or Trail Race
• Coming Next: Build Your First Fueling Plan