Fuelling for Hyrox: A Dietitian’s Perspective

If you have done Hyrox before, you know exactly what makes it hit different. It is not a straight endurance event and it is not a pure strength test. It is both at the same time. You are running hard, then dropping into heavy stations, then trying to settle straight back into pace again. That back and forth drains glycogen quickly and builds muscle fatigue faster than most people expect.

This is where good fuelling becomes a real advantage. When your energy stays steady, your legs stay responsive, your power holds under fatigue and your focus does not fade halfway through the course. With the right fuel, hydration and timing behind you, the whole race feels more controlled. Every station becomes more manageable and your recovery starts in a far better place once you cross the finish line.

Hyrox prep raises the overall demand on your body, no matter your starting point. The combination of running volume, strength endurance and high intensity conditioning means you are burning through more energy, creating more muscle fatigue and relying more heavily on hydration and recovery systems across the week.

When your fuelling matches that workload, you maintain better session quality, adapt more effectively and stay in a stronger position heading into race day. This demand can climb quickly without athletes realising it, especially on days where a run and a strength session fall back to back.

Before you think about race day timing or pre-event supplementation, it is important to remember that performance starts long before you enter the arena. Race day nutrition can help you feel your best, but it cannot make up for weeks of under-fuelling or inconsistent habits. The way you eat and hydrate throughout your Hyrox prep builds the foundation that race day nutrition sits on.

Carbohydrates are the primary fuel source for Hyrox because both the running and the strength endurance stations rely heavily on muscle glycogen. When carbohydrate availability is low, fatigue sets in earlier, pacing becomes harder to maintain and mental focus drops. Keeping carbohydrate intake high across your training week supports consistent performance, better adaptation and reduced risk of accumulated fatigue.

Hyrox creates repeated muscle breakdown due to the strength endurance demands of the event. Protein supports the repair and rebuilding of that tissue, maintains training adaptations and helps reduce next day soreness. Consistent intake across the day works best, rather than one large serve, to keep muscle protein synthesis elevated through your prep.

Even mild dehydration increases cardiovascular strain and can make high-intensity efforts feel harder than they should. Good hydration supports blood volume, thermoregulation and overall pacing. Electrolytes are especially useful on high sweat days, longer runs or double sessions, helping you maintain fluid balance and muscle function.

If your race is between 7am and 10am

Night before

• Choose a carb focused dinner to top up glycogen
  
  

• Keep foods simple and familiar
  
  

• Add electrolytes either with dinner or before bed
  
  

Morning of

• Begin hydrating as soon as you wake, include electrolytes
  
  

• Keep breakfast light with minimal protein, fat and fibre
  
  

• Choose fast acting carbs 1 to 2 hours before, like toast with honey, rice cakes, fruit or low fibre cereal
  
  

• Optional top up 30 to 45 minutes before with a gel or half a bar
  
  

If your race is between 11am and 2pm

• Breakfast should be mostly carbs with a small amount of protein
  
  

• Prioritise easy to digest options early in the day
  
  

• Eat again 2 to 3 hours before with a carb focused meal
  
  

• Snack 45 to 60 minutes before with simple sugars like fruit or a gel
  
  

• Hydrate steadily through the morning
  
  

• Keep fats, fibre and anything unfamiliar to a minimum
  
  
  

If your race is between 3pm and 5pm

• Breakfast: carbs plus moderate protein and fats
  
  

• Eat every 2 to 3 hours across the day
  
  

• Lunch should be carb heavy and familiar
  
  

• Reduce meal size as start time gets closer
  
  

• Switch to simple carbohydrate snacks
  
  

• Hydrate consistently
  
  

• If using caffeine, take it 45 to 60 minutes before your start time
  
  

If your race is after 6pm

• Breakfast: carbs plus moderate protein and fats
  
  

• Continue eating every 2 to 3 hours
  
  

• Have a larger carb based lunch
  
  

• Move to simple carbohydrate snacks later in the afternoon
  
  

• Hydrate all day with water and electrolytes
  
  

• If using caffeine, time it carefully as it may affect sleep
  

Not eating enough carbohydrates

Hyrox training uses far more glycogen than most athletes expect. Underfueling shows up as flat sessions and early fatigue on race day.

Relying on race day to fix underfueling

One good breakfast cannot reverse weeks of low energy availability.

Using too much caffeine

Too much too soon increases heart rate, disrupts pacing and can cause mid race crashes.

Arriving underhydrated

Hydration affects pacing, muscle function and overall stamina.

Trying new foods or supplements on race day

Unfamiliar choices increase the risk of gut upset.

Long gaps between meals for afternoon or evening races

This leads to low blood glucose and sluggish early pacing.

Skipping recovery nutrition

Delayed refuelling slows muscle repair and prolongs soreness.

Start with fluids and electrolytes

Replace water and sodium lost through sweat to support muscle function and reduce cramping.

Choose a simple carbohydrate option straight after

Smoothies, chocolate milk, fruit or carb drinks are easy to tolerate and replenish glycogen quickly.

Follow up with a proper meal within 2 to 3 hours

Aim for a familiar meal that combines carbs and protein to support deeper recovery.

Include steady protein across the afternoon or evening

Muscle repair continues for hours, so spread your protein intake.

Keep sipping water throughout the day

Hydration needs remain elevated for several hours after the event.

Creatine

Supports repeated strength efforts across sleds, carries and wall balls.

Electrolytes

Replace sodium lost through sweat and support hydration and pacing.

Magnesium

Supports normal muscle contraction and relaxation.

Carbohydrate powders or gels

Provide fast, reliable energy during longer or more intense efforts.

Protein

Helps meet recovery needs when appetite is low post-race.

Fueling for Hyrox is not just about race day. It is about building consistent habits that support your training load, help you hold better pace and allow you to recover more effectively. Race day fuelling becomes the final layer when the foundations are already in place.

Creatine, electrolytes, magnesium, carbohydrates and protein are the most reliable tools for performance once your daily nutrition is solid.

For more evidence-based guidance on hydration, gut health or everyday performance, explore our Education Hub for practical nutrition support.