Precision Fuel & Hydration was founded in 2011 to solve the highly individual race nutrition needs of endurance athletes. They work with many of the world’s top trail runners, including the winners of Western States 100, Cocodona 250 and CCC by UTMB, as well as elite athletes in triathlon and professional cycling.

What sets PF&H apart in the sports nutrition world is their focus on education. They provide knowledge and science-backed tools to help you tailor your fuel and hydration strategy to your specific event and your individual needs. On this page (scroll down), we’ve teamed up with our sports nutritionist Juli Brüning to break down this expert knowledge into a compact, easily digestible guide. Take some time to dive into race fueling and hydration.

Ahead of adidas INFINITE TRAILS, you can use their free Fuel & Hydration Planner to get a personalised strategy for your race. You’ll receive a plan that explains how much you should be aiming to eat and drink to help you perform at your best on race day. 

And to help you dial your strategy in before you get to the start line at Gastein, you can book a free 1:1 video consultation with a member of the PF&H Team, who’ll be happy to answer any questions you have about your race nutrition plan.

At adidas INFINITE TRAILS, the following PF&H products (tailored to each specific distance) will be available to fully support your fueling, electrolyte, and hydration needs:

• PH 1000 electrolytes
• PH 1500 electrolytes
• Carb & Electrolyte Drink Mix
• PF 30 Gels
• PF 30 Caffeine Gels
• PF 90 Gels
• PF 30 Chews
• PF 60 Chew Bars

To give you a clear overview of what’s available at each aid station, you’ll find a breakdown like this under every route description. Larger fueling sizes, such as the PF 90 Gel or PF 60 Chew Bar, are provided specifically when the sections between aid stations are long and highly demanding. Here is an example for the 60K:

Keen to try the on-course nutrition before race day? 

Remember: “nothing new on race day”. So, if you’re keen to test out the PF&H products during training, use the code AIT26 at the checkout to get 15% off your first order.

Juli Brüning is a trail runner, Nutrition Scientist and Performance Nutritionist specializing in endurance, team, and mountain sports. With academic expertise (B.Sc., M.Sc.) and personal experience as a competitive athlete, she combines science and real-world insight to create practical, individualized nutrition strategies. As part of the Athlete Support team at Precision Fuel & Hydration, she develops course-specific race nutrition plans — and as a Gastein local, she knows the terrain and the INFINITE TRAILS routes like no one else. Since many years she is an integral part of the adidas INFINITE TRAILS community. Juli and her team won the Team Mixed category at aIT in 2025. Juli helps athletes fuel sustainably, protect their well-being, and perform at their highest level.

This is Juli’s race nutrition strategy guide for you

Race nutrition isn’t rocket science — but only getting a few key principles right can unlock your full potential and make race day experience enjoyable.

Think of your body like a race car. To go fast and make it to the finish line, you need the right fuel, effective cooling, and a system that keeps everything running smoothly. That’s where your three race nutrition levers come in:

• Carbohydrates to fuel performance
• Fluids to stay hydrated
• Electrolytes to replace what you lose through sweat and support key body function as heat and effort build up

Together, they help maintain energy, support performance, and keep your body working efficiently over long distances.

Fuel the engine. Cool the system. Keep moving forward.

Caffeine:
Caffeine can be a powerful performance tool — if you treat it like strategy, not guesswork. Doses around 3–6 mg/kg bodyweight can help reduce perceived fatigue and sharpen focus. It typically takes ~45 minutes to kick in with PF30 Caf Gels, and has a long half-life of ~4–5 hours — meaning timing matters as much as dose. Used well, it can make effort feel more manageable; used poorly, it can turn race day into a jittery rollercoaster with side effects like anxiety, GI distress, or overheating and it‘s highly individual. So, more isn‘t always better.  You don’t have to take it all at once — smaller, well-timed doses often work best.

On AIT race courses, the PF 30 Caffeine Gel setup is built exactly around these numbers, so you can start smart and maintain steadily through the race without doing mental espresso math mid-climb. They all contain 100mg of caffeine per gel – for reference: 1 espresso ≈ ~75 mg caffeine. Now’s the time to get familiar with aid station offerings across your race distance — not on race day when your brain is already negotiating early retirement.

Test it in training, find your rhythm, and keep it boringly consistent when it counts.

If you’re considering adding caffeine to your adidas INFINITE TRAILS race strategy and want to dive even deeper into the details, there’s a great PF&H blog covering everything from timing and dosage to common mistakes and practical race-day use.

Carbs are king — but how much do you actually need? 60, 90, or even 120+ g/hour?

Fuel intake during racing depends on:

• exercise intensity
• race duration
• and your gut’s ability to absorb carbohydrates efficiently

The longer and harder you go, the more fuel your body typically needs. Besides pace & duration, your ideal carb intake depends how well your gut is trained to tolerate and absorb fuel during exercise.

That‘s why you should train your gut like you train your legs.

Hitting 60, 75 or even 90+ g of carbohydrates per hour means taking in a steady stream of simple carbs — essentially sugar delivered consistently over time. That can feel like a lot for your gut to handle at race intensity, but the good news is: you can train it.

Once you’ve worked out how much you need:

• Train your gut 1–2 times per week starting from your current tolerable intake.
• Gradually increase carbohydrate intake by 5–10 g per hour per week.
• Building up to more than 20% above your planned race-day target.
• Use your key long and high-intensity sessions to practice.
• On race day, bring it back to down.

Start simple: little and often usually works better than large amounts at once.

Smaller doses, steadier absorption, better comfort.

The same applies to fluids. Once you know your sweat rate, longer races and hot or humid conditions often require high fluid intakes. Knowing the numbers is one thing — consistently tolerating and absorbing them is another. Your gut can also be trained to handle higher fluid volumes more comfortably and improve fluid absorption during exercise. Consistency beats quantity spikes!

When you sweat, you’re not just losing fluid — you’re also losing electrolytes, especially sodium, which is the most abundant one lost in sweat.

If you don’t replace enough of it, you could run into hydration-related issues like:

• muscle cramps
• GI distress (nausea, urgency, etc.)
• bloating or swelling
• reduced carbohydrate absorption
• overheating
• and a noticeable drop in performance — especially in heat or over long distances

None of these are “minor inconveniences” on race day — they’re the kind that can turn a strong race into a long walk you didn’t plan for.

How salty you sweat is largely genetically determined and highly individual – ranging from from as little as 200 mg per liter of sweat to more than 2,000mg/L. That’s a huge spread, which is exactly why a one-size-fits-all hydration plan doesn’t work, especially in trail races where conditions can change fast. Your friends hydration strategy isn‘t your hydration strategy, even if they swear by it on Strava.

If you want to know exactly how much sodium you lose, an advanced Sweat Test can measure your individual sweat sodium concentration and help us personalise your hydration strategy to your needs — not averages.

Your “saltyness” is not only largely genetically determined, but also, unlike fitness, it doesn’t really change much after infancy. Which is good news, because it means you only need to get it tested once in your life.

And honestly… it’s probably the only performance test where you just sit there and do nothing.

The test is:

• non-invasive
• done completely at rest
•  ~45 minutes total, including a detailed debrief and personalised hydration plan

There are multiple PF&H Sweat Test Centres around the world, with the test typically costing ~€145. You can find them HERE — or you can get tested locally, or at my mobile Sweat Test Pop-Up Events: Sweat Testing with Juli.

And if you’re wondering what it actually looks like… here’s a video of the test in action

Because guessing your sodium needs on race day is a fun game… until it isn’t.

Everyone is not only differently salty, but also differently sweaty. And while the same factors influence sweat losses, where you sit on the spectrum is highly individual.

Fluid needs during a race depend on how much you sweat — and that varies from person to person, day to day, and even within the same day depending on:

• temperature & humidity
• exercise intensity
• heat acclimation
• what you’re wearing (because sweat only cools you when it can evaporate)

As a result, sweat rates can range from ~0.3 L/hour in cool conditions up to 2–3 L/hour in hot conditions and high-intensity efforts.

Most runners tend to perform well around:

• 300–600 ml/hour in moderate conditions (~10–15°C)
• 600–900 ml/hour in warmer or longer efforts
• >1 L/hour in hot conditions and ultras

There is no “one-size-fits-all” number here — only your number. And the only way to find it is by testing in training, ideally in race-like conditions.

Science suggests you can generally tolerate around 2–4% body weight loss through sweat before performance meaningfully declines — meaning you don’t need to replace everything you lose, just stay within the effective range.

If you’ve experienced issues like unusual fatigue, elevated heart rate, or GI distress in the past, hydration (or underhydration) may have played a role. Getting this right helps support key systems during racing, including:

• maintaining blood volume for efficient heart function
• regulating core temperature to delay overheating
• supporting gut function by preserving blood flow during exercise

To fine-tune hydration, sweat rate testing is the most effective way to personalise your plan — you can find sweat rate measurement instructions HERE.

For electrolytes, the goal is to match the sodium concentration of your sweat within your fluids.
For example, if your sweat contains ~1,000 mg sodium per litre, then a 500 ml flask would ideally contain ~500 mg of sodium — helping you replace what you lose, proportionally, as you go.

That felt like a bit of a fast-paced jog through nutrition science and we might have dropped half the group there…

If you’ve got questions, don’t guess — talk to a real human. You can book a free 20-minute 1:1 video consultation with one of the PF&H team experts to go through everything properly.

They’re used to being hit with every question under the sun — and genuinely love helping athletes dial things in.

Book your call HERE.

Okay — now we know your numbers… but how do you actually hit them?

You’ve got multiple options to build your carb intake based on personal preference, logistics, and aid station availability. Every product clearly shows its carbohydrate content on the front, so you can mix and match with confidence.

With options like PF30 Gels, PF30 Chews (2 × 15 g carb blocks), PF60 Chew Bars, or the PF90 Gel pouch, there’s a system for every race strategy — from steady sipping to simplified fueling plans.

You can vary textures and formats to help reduce flavour fatigue, avoid palate overload, and keep intake feeling manageable over long hours.

Or… you can keep it beautifully simple:
1 × PF90 Gel per hour for 4, 6, or even 7 hours of racing — if you’re targeting ~90 g/hour and keeping fuel and hydration separate.

On top of that, you can also use liquid carbohydrates via the Carb & Electrolyte Drink Mix, which combines both fuel and sodium in one system — efficient, practical, and race-friendly.

No overthinking. Just consistent fueling that fits your race.

How to hit your numbers

Looking at the chart, you’ll notice there are multiple ways to hit your carbohydrate, fluid, sodium, and caffeine targets — combined or separate, liquid or solid, with or without caffeine.

There’s no universally “best” strategy here. Every approach comes with its own benefits and trade-offs, and what works brilliantly for one athlete might feel completely wrong for another. Race duration, intensity, temperature, logistics, and personal preference all play a role.

What matters most is not the perfect plan — it’s having a plan you’ve actually practiced.

Arrive on race day knowing what you’ll take, when you’ll take it, and that your gut, brain, and legs have already rehearsed the script.

With both the PH 1000 Electrolyte Drink and the PF Carb & Electrolyte Drink Mix available at aid stations across the race courses, it’s important to understand the difference — because they’re designed for two different jobs.

The PH 1000 is a hydration-focused drink. It’s an effervescent tablet dissolved in water, primarily delivering electrolytes at a strength of 1,000 mg sodium per litre, with virtually no carbohydrates. It uses a small amount of sweetener (sucralose) for taste, but its main role is simple: replace sodium and support hydration.

The PF Carb & Electrolyte Drink Mix, on the other hand, is fuel + hydration in one. It also provides 1,000 mg sodium per litre, but adds 60 g of carbohydrates per litre in a 2:1 glucose-to-fructose ratio, supporting higher carbohydrate absorption rates during racing.

That 1,000 mg/L sodium level is designed to match the needs of an “average salty sweater” (typically ~850–950 mg/L). If you’re saltier, you can increase sodium intake by adding electrolyte capsules. If you’re less salty, simply dilute with additional water to bring the concentration down.

Two drinks, two roles — same system, different jobs.

Carb Loading – 48 hours

Carb loading is a strategic way to top off your glycogen stores before race day – so you start fully fueled, delay fatigue, and sustain performance for longer efforts.

Your body’s carbohydrate stores (glycogen) are fairly limited — and at race intensity they run low fast. After ~90 minutes of moderate to hard effort, performance starts to fade. That’s usually when things feel like: legs get heavy, pace drops, your brain starts negotiating deals you didn’t agree to. You don’t hit the wall because you’re unfit. You hit it because the tank is empty.

Once muscle glycogen is gone, it’s gone. That’s why maintaining high carbohydrate availability before and during longer efforts is key for performance.

How it works

When you eat carbs, they’re broken down into glucose and stored as glycogen. That glycogen lives in two main places:

• Liver glycogen keeps your brain running and blood glucose stable — even overnight while you sleep
• Muscle glycogen is stored inside working muscles and acts as your race fuel tank, used directly when you train or compete

How much you need

Science suggests 8–12 g of carbs per kg of body weight per day. For a 70 kg athlete, that’s roughly 480–840 g of carbs per day — or around 10 cups of cooked white rice. Which is a lot. And without practice, it can backfire — leaving you feeling overly full, sluggish, or bloated. If you’ve never carb loaded before, start more conservatively at around 6 g/kg body weight.

Don’t just „carb load“ with anything!

Cakes, fries, cookies and ice cream technically contain carbs.

But… for them, it’s a no: High-fat foods slow digestion, make it harder to reach carb targets, and fill you up before you’ve actually topped off glycogen stores. You end up “comfortably stuffed” instead of fully fueled.

On top of that, high fat intake before racing increases the risk of GI issues on course.

(Keep the ice cream for after the finish line — it always hits better there anyway.)

What actually works

Carb loading is not the time for experimentation. It’s about simple, familiar, easy-to-digest foods.
Stick to:

• white rice, white pasta, rice noodles
• potatoes (no skin)
• white toast/plain bagels with honey or jam
• (banana) pancakes with syrup
• PF30 chews, chew bars, carb drink mixes and gummy bears
• fruit juice, bananas, fruit pouches
• low-fiber cereals, crackers

Think:
Low fiber, low fat, moderate protein, high carbs.

Don’t show up underloaded. Show up with a full tank, steady legs, and nothing left to guess.

Pre-race breakfast:
3–4 hours before your race starts, aim for a carb-rich, low-fat, low-fibre, and low-protein breakfast to top up energy stores without upsetting your gut.

A simple rule of thumb: match carbs to timing.

• ~3 hours before start → ~3 g carbs/kg body weight
• ~2 hours before start → ~2 g carbs/kg body weight

The closer you get to the start, the lighter and simpler it should be — same principles as your carb-loading strategy, just more race-specific and dialled in.

Think familiar, easy-to-digest options like:

• rice pudding with maple syrup
• cornflakes with milk or plant milk
• porridge with banana (if you tolerate it well)

Nothing new, nothing heavy — just topping up the tank without asking your stomach to do any extra work on race morning.

Prehydration (“Preloading”)
To start your race properly hydrated, it’s worth using a simple strategy called prehydration. The idea is to increase fluid with sodium availability before the start so your body goes into the race topped up — not catching up.

A practical approach: Drink 1 × PH 1500 tablet in 500 ml water the evening before your race, and again on race morning. Aim to finish your bottle 90–60 minutes before the start, giving your body time to absorb what it needs and settle before the gun goes off.

Preloading isn’t about multiple nervous toilet stops — it does the opposite. It reduces the classic “just one more time…” loop into a single, well-timed bathroom stop, while allowing you to retain the fluid and sodium that actually matters for performance.

Simple goal:
Arrive on the start line hydrated, calm, and not queueing at the toilets for the fifth time.

Grab your PH1500 bottle, head out for your final pre-race walk to the AlpenArena, sip steadily on the way, and drop your bag at the Alpentherme — bikini, flip-flops, post-race party mindset included.

Finish your bottle in time, take your one final bathroom stop, and get to the start line ready to race.

Final pre-start top-up:
In the final 30–15 minutes before the gun goes off, take a small, easy-to-digest carbohydrate hit — around ~30 g of simple carbs, for example 1 × PF30 Gel or PF30 Chew.

This acts as a final “on-switch” for your system — topping up circulating energy and ensuring you’ve got readily available fuel right as the race begins, while still preserving your stored glycogen for later in the effort.

To help guide your race nutrition, you can use the free PF&H Fuel & Hydration Planner to get a solid starting point for your individual targets. From there, you can refine your strategy using our adidas Infinite Trails guide here — or dial it in further with a free 1:1 video consultation with one of the PF&H team experts.

This is how your results appear in the Fuel & Hydration Planner. The question marks indicate what’s available on course and provide quick, practical tips to help you refine your strategy