What Electrolytes Do Runners Actually Need?

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Hydration is one of those topics that everyone thinks they understands — but very few runners actually do in practice.

Most runners know they should drink water.

Most runners have heard electrolytes matter.

But when you ask runners:

• How much should you drink?
• Which electrolytes matter?
• How do you actually hydrate your runs?

The answers are usually vague or inconsistent.

This week in the Performance Nutrition Protocol, we’re focusing on building a simple, repeatable hydration strategy that works for the average runner — something you can execute consistently without overthinking.

This is Hydration & Electrolytes 101.

We can always make it more precise later.

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Why Hydration and Electrolytes Matter

When you run, you lose fluid through sweat.

You also lose electrolytes — especially sodium.

Some runners sweat very little.

Some runners sweat a lot.

But across large groups of runners, sweat rate follows a bell curve.

The average runner loses about 1 liter of fluid per hour, which is roughly a large 32-oz water bottle.

If you don’t replace some of that fluid:

• Dehydration sets in
• Performance drops
• Recovery is hindered

Electrolytes matter because sweat isn’t just water.

When we sweat, we lose sodium — and sodium is the primary electrolyte runners need to pay attention to.

If you get sodium roughly right, the other electrolytes tend to take care of themselves.

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How to Hydrate Your Runs: A Simple Strategy

We’re going to break hydration into two parts:

1. Fluid
2. Electrolytes (specifically sodium)

Fluid Intake

A practical rule of thumb for runners is to replace about half of your fluid losses during a run.

If the average runner loses:

• ~1 liter per hour (about one large water bottle)

Then a good starting point is:

• ~500 mL per hour or ~16 oz per hour or One small water bottle per hour

This avoids both under-hydration and over-hydration.

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Electrolytes: Focus on Sodium

Sodium losses vary widely between runners.

Some runners have very watery sweat.

Others are very salty sweaters — they often notice white salt marks on their clothes or can taste salt on their skin.

Typical ranges look like this:

• Low end: ~200 mg sodium per liter
• High end: ~2,000 mg sodium per liter

But again, we’re not chasing perfection here.

The average runner’s sweat sodium concentration is about 1,000 mg per liter.

That makes it an excellent starting point.

When you’re hydrating during workouts, aim for:

• ~1,000 mg of sodium per liter of fluid

To do this, you can use electrolyte tablets or sachets that mix at that concentration.

Many popular sports drinks only provide 200–400 mg per liter, which is often too low for longer runs or hot conditions.

Two brands that consistently hit the right range are:

• LMNT
• Precision Fuel & Hydration

If you use a different brand, check the label.

The number matters more than the brand name.

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This Week’s Performance Nutrition Habit

This week’s habit is about learning how to hydrate properly, not optimizing every detail.

The habit is:

Hydrate every workout with electrolyte fluid (1 small bottle per hour)

To make this simple and repeatable, follow these steps:

Step 1: Create Your Electrolyte Bottle

Grab a small water bottle and label it “Electrolyte Fluid.”

This becomes your default bottle for runs.

Step 2: Add Sodium

Use a 1,000 mg sodium electrolyte tablet or sachet.

Add it to your bottle and mix it with water.

Step 3: Drink to Match Duration

Drink one small bottle per hour of running.

• 30-minute run → half a bottle
• 2-hour run → two bottles

Simple.

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Track the Habit

Download and print the ​Performance Nutrition Habit Tracker​

In the habit column, write:

“Hydrate run with electrolyte fluid.”

Each day you complete the habit, give it a tick.

If you don’t have a run scheduled, you still tick the day.

The goal is consistency and awareness, not perfection.

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A Note on Precision

You may notice we’re not worrying about:

• Exact bottle sizes
• Exact mixing ratios for different volumes
• Dialing sodium down to the milligram

That’s deliberate.

We don’t want perfection to become the enemy of execution.

For now:

• Small bottle
• 1,000 mg sodium
• Drink it consistently

Once this habit is established, then it makes sense to get more precise — especially for long runs and hot conditions.

I have a podcast interview with ​Andy Blow from Precision Hydration​, as well as another episode on ​Hydrating for the Long Run​ where I go deeper into individualized hydration strategies, if you want to learn more.

But for this week, keep it simple.

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The Plan This Week

1. Grab a small water bottle and label it “Electrolyte Fluid”
2. Add a 1,000 mg sodium tablet or sachet
3. Drink one bottle per hour when running
4. Track it on your ​Habit Tracker​

Build the habit now — so when longer and hotter runs arrive, you’re ready.