Race Nutrition, Sweat Loss & Sodium Essentials

Most runners know they “should probably consume more” on race day. Some have heard the magic number: 80–90 grams of carbs per hour. Others rely on a few gels and hope their stomach holds up.

But great performance — especially in trail & ultra races — isn’t built on generic rules or one-size-fits-all plans. It’s built on understanding your body, your sweat, your physiology, and your race demands.

That’s why at Trail Addiction Coaching, we don’t guess.
We use carbohydrate planning, sweat rate testing, and sodium profiling to build a personalised race nutrition strategy.

Why Race Nutrition Is One of the Most Important — and Overlooked — Parts of Performance

You can be the fittest athlete at the start line, but without the right fuel plan you can still end up with:

• Gut distress

• Early fatigue

• Dizziness or nausea

• Loss of power

• Muscle cramping

• A slow fade in the second half

• DNFs that had nothing to do with fitness

Correct race nutrition is the bridge between training potential and race execution.

Done properly, it lets you:

• Hold pace longer

• Avoid energy crashes

• Prevent gut blow-ups

• Maintain hydration balance

• Maximise carbohydrate oxidation

• Perform consistently across long climbs & variable terrain

Let’s break the main components down.

1. Carbohydrate Intake: More Than Just “x Grams per Hour”

Yes — research consistently shows athletes perform best on 80–120 grams of carbohydrate per hour during long endurance races.

But it’s not that simple.

Why we don’t give every athlete the same carb target

At Trail Addiction Coaching, we look at:

• Race intensity
  Higher effort = higher carbohydrate burn

• Duration
  A 3-hour event has different needs than a 12-hour ultra

• Terrain & topography
  Steep climbs demand different fueling than runnable flats

• Gut tolerance and past issues
  Some athletes need a build-up phase to avoid GI distress

• Environmental conditions
  Heat affects gut absorption significantly

• Product preference & mixing
  Gels vs. chews vs. liquids vs. real food

Your optimum carb intake is personal — and trainable.

Why gut training matters

The gut adapts just like the muscles do.
When we progressively increase carb intake in training, we improve:

• Gastric emptying

• Intestinal absorption

• Fuel tolerance under stress

This reduces the risk of stomach problems on race day and increases usable energy by 20–40%.

2. Sweat Loss: Why We Test It Instead of Guessing

Sweat rate is one of the biggest performance variables, yet most athletes have no idea how much fluid they actually lose.

Two athletes running side-by-side, same pace, same temperature, can differ by 1–2 litres per hour in sweat loss.

Why this matters

If you lose more fluid than you replace, you risk:

• Cardiac drift (HR rising at the same pace)

• Lower blood plasma volume

• Earlier fatigue

• Cognitive decline

• GI upset

• Heat illness

Conversely, over-drinking can lead to:

• Hyponatremia (dangerously low sodium)

• Nausea

• Bloating

• Reduced performance

Sweat testing tells us:

• How much you sweat per hour in different conditions

• Whether you’re a light, moderate, or heavy sweater

• How much fluid you should aim to replace per hour

• How your sweat rate changes with intensity

This gives us the foundation for a proper hydration strategy.

3. Sodium Intake: The Key That Most Athletes Miss

Sodium replacement isn’t optional — it’s essential.

When you sweat, you don’t just lose water. You lose electrolytes, especially sodium. For some athletes, sweat sodium losses are 600 mg per litre.
For heavy salt sweaters, that number can be 1,500–2,000 mg per litre.

Why sodium matters

Sodium helps:

• Maintain blood volume

• Support thermoregulation

• Reduce muscle cramping

• Aid fluid absorption

• Stabilise the gut

Too little sodium → nausea, bloating, cramps, dizziness.
Too much sodium without enough water → dehydration and high gastric concentration.

The sodium–gut connection

A well-balanced sodium intake:

• Helps move fluid through the stomach

• Improves carbohydrate uptake

• Lowers GI symptoms

• Supports sustainable energy delivery

This is why appropriate sodium intake is a performance enhancer, not just a “nice to have”.

4. Why We Decided to Offer Sweat Testing

Because guessing doesn’t work.

We’ve seen countless athletes:

• Take salt tablets blindly

• Drink either far too much or too little

• Follow generic advice unrelated to their physiology

• Get severe gut issues because sodium wasn’t balanced

• Under-fuel because their stomach “shut down” during a race

• Experience cramping they assumed was due to fitness, not sodium

• Fail to hit carb targets because hydration wasn’t supporting absorption

Sweat testing solves these problems by giving your personalised numbers.

We measure:

• Sweat rate

• Sodium loss

• Fluid requirements

• Sodium replacement needs

• Carbohydrate intake compatible with fluid intake

It’s all connected.
Hydration impacts gut absorption.
Sodium impacts hydration.
Carbs depend on both.

Your strategy must be integrated — and personalised.

5. Personalised Race Nutrition: How We Build Your Plan

At Trail Addiction Coaching, we don’t just hand you a spreadsheet.
We build a fully integrated plan based on:

✔ Race intensity & pacing strategy

Higher intensity = higher carb requirement = higher sodium needs.

✔ Topography & elevation gain

Climbs spike HR → changes fuel and hydration needs.

✔ Temperature & humidity

We adjust fluid and sodium targets for heat or cold.

✔ Athlete sweat profile

Heavy sweaters need very different plans than low sweaters.

✔ Gut training & tolerance

We match product type and volume to what your body handles best.

✔ Aid station spacing

Fuel strategy is built around course logistics.

✔ Duration-specific targets

5-hour ultras vs. 12-hour vs. 20-hour require totally different approaches.

✔ Preferred products

We work with what you enjoy — so you actually stick to the plan.

6. The End Result: You Race Stronger, Longer, Smarter

A proper race nutrition strategy gives you:

• Stable energy

• Strong gut function

• Better power output

• Reduced cramping

• Less dehydration

• More confident pacing

• A calmer stomach

• Faster recovery

• A far better race experience

This is the difference between surviving a race and performing in a race.

Ready to Unlock Your Best Race Performance?

Trail Addiction Coaching now offers:

• Sweat rate testing

• Sodium loss profiling

• Carb intake planning based on YOUR physiology

• Race nutrition strategy for specific events

• Training plans that integrate fueling targets into sessions

• Ongoing support to refine the plan

If you want to train and race with confidence — not confusion — visit:

trailaddictioncoaching.com

Or reach out and book a consultation.

Your fitness is earned in training.
Your performance is unlocked with your fueling.
We help you master both.