HYROX Energy Supply Techniques

1Why Fueling is the Hidden Key in HYROX

HYROX is a high-intensity, long-duration hybrid event – 8 km of running interspersed with 8 high-load equipment stations (SkiErg / Sled Push & Pull / Burpee Broad Jump / Row / Farmer's Walk / Sandbag Lunges / Wall Balls). Most finishers complete the race in 60 to 90 minutes.

At this intensity:

• Muscles primarily use carbohydrates as fuel – at intensities above approximately 75% VO₂max, fat energy cannot keep up with power demands, and carbohydrates (muscle glycogen / liver glycogen / blood glucose) become the dominant substrate (Gastin, Sports Med 2001)
• Glycogen is depleted at an extremely high rate – glycogen steadily decreases during the running segments, and its depletion accelerates during equipment stations due to high local power output (low glycogen in quadriceps and glutes is a core reason for pace drops in the latter half)
• Once glycogen is insufficient → power output and running economy both decline, leading to a performance collapse in the second half

Conclusion: Energy fueling is not an optional extra, but a critical variable that directly determines performance in the later stages.

• Gastin PB, Sports Med 2001；Jeukendrup & Gleeson, Sport Nutrition 4th ed. 2024

2Energy Systems: Why Carbs?

At exercise intensities above the threshold, the rate of fat oxidation cannot keep up with power demands, making carbohydrates the primary fuel. The differences in power and efficiency among the three energy systems determine the fueling strategy for different race segments:

The 30+ ATP for aerobic oxidation refers to complete glucose oxidation (not glycolysis itself); the phosphagen system is responsible for seconds-long bursts, providing immediate power for equipment stations.

• Gastin, Sports Med 2001

3Pre-Race Foundation: Glycogen Loading

For events that immediately demand high carbohydrate expenditure, the key leverage is to fully load glycogen before the race, rather than focusing on mid-race supplementation.

Scientific Basis

• Evidence shows that combining rest days with a high-carbohydrate diet (approx. 10 g carbohydrates per kg body weight) can achieve full muscle glycogen levels within 24 hours, eliminating the need for traditional depletion-supercompensation cycles (Bussau et al., Eur J Appl Physiol 2002)
• Modern carbohydrate loading protocols (Sherman / 3-day method): reduced pre-race training (taper) + increased carbohydrate intake to 8–12 g/kg/day; the old 7-day depletion period has been discarded

Execution Points

1. 2–3 days before the race: Distribute high carbohydrates throughout the day (low fiber, easy to digest – white rice/white bread/bagels/fruit juice/bananas), aiming for 8–10 g/kg/day (newcomers start with 6–8).
2. Race morning (2–3 hours before start): High-carb, low-fiber meal (bagel + jam / oats + banana / toast + honey), approx. 2–3 g/kg carbohydrates.
3. Approximately 15 minutes before start: Take another GO Isotonic Energy Gel (22 g carbohydrates, isotonic formula requires no water) or half a BETA Fuel Gel (20 g carbohydrates) to raise blood sugar and activate carbohydrate metabolism pathways. If water is not convenient in the starting area, isotonic gels can be consumed directly; if you want to eat on the go, BETA Fuel Energy Chews are also an option.

• Burke/Deakin 2021; Bangsbo et al. 2025 Copenhagen Consensus
• Bussau et al., Eur J Appl Physiol 2002；Burke LM, Deakin V. Clinical Sports Nutrition, 6th ed. 2021

4Individual Race: Mid-Race Fueling Plan

Most HYROX individual finishers complete the race in 60–90 minutes. Pre-race loading is usually sufficient; mid-race energy gels are an optional enhancement.

Configuration Table by Finish Time

Pre-Race Top-up (approximately 15 minutes before start)

• Supplement with approximately 22–30 g carbohydrates:
• 1 GO Isotonic Energy Gel (22 g carbohydrates, isotonic, no water needed)
• or half a BETA Fuel Gel (20 g carbohydrates)
• or 1 banana (approx. 25–30 g carbohydrates)
• Purpose: Raise blood sugar and activate carbohydrate metabolism enzymes

Practical Reminders

• Energy gels must be consumed with water at aid stations in the transition zone – no water bottles are allowed into the equipment stations
• All new products/flavors must be tested in training first (gut training principle): Practice with GO Isotonic Gel in simulated training to accustom your gut to the carbohydrate flow rate on race day
• It is recommended to pair with GO Hydro electrolyte tablets or HYDRO+ electrolyte powder to replenish water and sodium at each aid station (especially in hot environments or when sweating heavily)

• Jeukendrup, Sports Med 2014；HYROX Race Nutrition Consensus；SiS Official Blog Running Nutrition Guide

5Energy Gel Carbohydrate Budget

Energy gels are a long-term strategy, not a last-minute emergency solution when you feel tired.

Carbohydrate Requirements for HYROX

Most finishers complete the race in 60–90 minutes, which falls within the low to moderate fueling needs range:

Why 90 g/h is not necessary

• Single-source carbohydrate (glucose/maltodextrin only) intestinal absorption limit ≈ 60 g/h (SGLT1 transporter saturation)
• Exceeding 60 g/h requires dual-source carbohydrates (glucose + fructose, optimized ratio to 1:0.8), which can push absorption to 90–120 g/h
• However, high dual-source intake requires 2–4 weeks of gut training to tolerate; otherwise, the risk of gastrointestinal distress significantly increases
• For HYROX with a 60–90 minute finish time, a single GO Isotonic Gel (22 g) or BETA Fuel Gel (40 g) already covers most people's needs – there's no need to blindly push to 90 g/h

• Jeukendrup, Sports Med 2014
• Currell & Jeukendrup, Med Sci Sports Exerc 2008; Hearris et al., J Appl Physiol 2022
• Cox et al., J Appl Physiol 2010
• Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med 2014, 44(Suppl 1):S25–S33.

6Glycogen Depletion Curve

• Glycogen in running segments decreases steadily and linearly;
• Upon entering equipment stations, due to localized high-power output (especially leg-driven Sled Push/Pull, Wall Balls), the rate of glycogen depletion steeply increases;
• In the latter half (stations 6–8), quadriceps and glute glycogen stores are already low – this is the root cause of slowing down and form breakdown later in the race;
• Pre-emptive fueling (rather than waiting until feeling tired) can inject fuel before the steep decline, delaying the inflection point

• SiS Official Blog How Not To Hit The Wall (schematic diagram)

7Doubles Race: Energy Gel Configuration

In a doubles race, both partners run all 8 km together, only sharing the repetitions at the equipment stations. Finish times are typically faster than singles, and there's a built-in recovery window during equipment stations.

Therefore, in-race fueling needs are lower:

Doubles Execution Tips

• Before the race, each person should consume about 30g top-up (GO Isotonic Gel or half a BETA Fuel Gel), staggering intake by 2–3 minutes to avoid simultaneous stomach discomfort
• Only if the projected finish time exceeds 90 minutes, or if individual equipment station allocation is significantly uneven, does each person need 1–2 energy gels
• Utilize the downtime while your teammate is at an equipment station to drink water/replenish electrolytes – this is a unique fueling advantage in doubles races

• HYROX Race Rules; Jeukendrup, Sports Med 2014

8On-Course Fueling Map: How to Fuel Across 8 Stations

Basic Rules

• Water is only available at designated water points in the transition zones; gels must be taken with water, and water cups cannot be taken into equipment stations
• Run 1 km between each station → enter equipment station → complete movements → return to transition zone → continue to next km

8-Station Fueling Allocation (SiS Products Version)

Specific Implementation

① Before Station 5 (Rowing Machine) — Key Window for the First Gel

• This is a crucial window at the halfway point of the race (approx. 40–50 minutes), before the glycogen curve begins to drop sharply.
• Recommendation: 1 GO Isotonic Energy Gel (22 g carbohydrates) or 1 BETA Fuel Gel (40 g carbohydrates, if you are already gut-trained for dual-source formulas).
• Must be consumed with water at the transition aid station; do not consume dry.
• If the weather is hot/you are sweating a lot, also add 1 GO Hydro effervescent tablet (345 mg sodium + potassium/calcium/magnesium) to the water at this station.

② Before Station 7 (Sandbag Lunges) — Second Gel (Conditional)

• Only if you anticipate finishing in over 90 minutes will a second gel be necessary.
• Most participants finishing in 60–75 minutes will have little time left at this station and no longer need additional carbohydrates – pre-race loading + the first gel should be sufficient until the finish line.
• If a supplement is needed: GO Energy + Caffeine Gel (22 g carbohydrates + 75 mg caffeine) can provide a boost and reduce perceived effort in the final stages; or continue with BETA Fuel Gel to maintain high carbohydrate delivery.

Sodium/Hydration Reminder

• Throughout the race, it is recommended to drink water in small, regular sips at each transition aid station (400–800 ml/h, adjusted for sweat rate).
• In hot environments or for heavy sweaters: add 1 GO Hydro tablet or 1 sachet of HYDRO+ (350 mg sodium) to each liter of water to maintain plasma volume and neuromuscular function (Maughan et al., Br J Sports Med 2018; Shirreffs & Maughan, Am J Physiol 1998).
• Avoid drinking only plain water – excessive plain water risks diluting blood sodium (especially important for female athletes) (Noakes et al., Proc Natl Acad Sci USA 2005).

• Hybrid Fitness Racing Official Rules Manual 25/26; Race Nutrition Consensus; SiS Official Blog Sodium for Endurance Athletes

Appendix: Quick Reference for Supplement Products (e.g., SiS series)

The following are examples of optional products by scenario, not mandatory; please choose based on personal training habits and gut tolerance, and always try new products during training first.

• Jeukendrup A, Gleeson M. Sport Nutrition, 4th ed. Human Kinetics, 2024. ISBN 9781718221734. Open Library
• Bangsbo J, et al. Consensus statements—Optimising performance of the elite athlete. Scand J Med Sci Sports 2025, 35(8):e70112. DOI PubMed
• Maughan RJ, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med 2018, 52(7):439–455. DOI PubMed
• Burke LM, Deakin V, Minehan M. Clinical Sports Nutrition, 6th ed. McGraw-Hill Education, 2021. ISBN 9781760425647. Open Library
• Gastin PB. Energy system interaction and relative contribution during maximal exercise. Sports Med 2001, 31(10):725–741. DOI PubMed
• Bussau VA, et al. Carbohydrate loading in human muscle: an improved 1 day protocol. Eur J Appl Physiol 2002, 87(3):290–295. DOI PubMed
• Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med 2014, 44(Suppl 1):S25–S33. DOI PubMed
• Currell K, Jeukendrup A. Superior endurance performance with ingestion of multiple transportable carbohydrates. Med Sci Sports Exerc 2008, 40(2):275–281. DOI PubMed
• Hearris MA, et al. 13C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or coingestion. J Appl Physiol 2022, 132(6):1394–1406. DOI PubMed
• Cox GR, et al. Daily training with high carbohydrate availability increases exogenous carbohydrate oxidation during endurance cycling. J Appl Physiol 2010, 109(1):126–134. DOI PubMed
• Shirreffs SM, Maughan RJ. Volume repletion after exercise-induced volume depletion in humans: replacement of water and sodium losses. Am J Physiol 1998, 274(5):F868–F875. DOI PubMed
• Noakes TD, et al. Three independent biological mechanisms cause exercise-associated hyponatremia. Proc Natl Acad Sci USA 2005, 102(51):18550–18555. DOI PubMed
• SiS Official Blog：Running Nutrition Guide / How To Fuel a Marathon on Race Day / Sodium for Endurance Athletes / Inside the Science of Gut Training / The 60/90/120 Debate（scienceinsport.com/sports-nutrition/）