Guide
What should you eat and take on HYROX race day?
On race day, eat what you already know from training and keep it light. Caffeine can help: the ISSN gives 3 to 6 mg per kg of body weight, usually about 60 minutes beforehand, with on average 2 to 4% better endurance performance. For 80 kg that is 240 to 480 mg. For eating during a race of about 75 minutes there is no fixed number; for efforts up to 1 hour a carbohydrate mouth rinse may be enough. Test everything in a sim first.
In short
- Caffeine according to the ISSN (Guest et al., 2021) is 3 to 6 mg per kg, usually about 60 minutes before the start.
- At 70 kg that is 210 to 420 mg, at 80 kg 240 to 480 mg. An effect is possible from 2 mg/kg.
- The average effect on endurance performance is 2 to 4%, with large differences between people.
- For a race around 1:15 we don't give grams per hour; for 30 minutes to 1 hour a carbohydrate mouth rinse may be enough (Jeukendrup, 2014).
- Try nothing new on race day. With health problems, medication or pregnancy, talk to a doctor first.
How much caffeine should you take before a HYROX race?
Work with 3 to 6 mg per kg of body weight. That is the range in the position stand of the International Society of Sports Nutrition (Guest et al., 2021). An effect is possible from 2 mg per kg, and according to the authors 9 mg per kg is not necessary.
The calculation is simple: mg of caffeine = body weight in kg × 3 to 6.
| Body weight | Lower limit (2 mg/kg) | 3 mg/kg | 6 mg/kg |
|---|---|---|---|
| 70 kg | 140 mg | 210 mg | 420 mg |
| 80 kg | 160 mg | 240 mg | 480 mg |
Check the packaging of your gel, shot or tablet for how much caffeine it contains and work back to your own weight. Start at the low end in your first test. If 3 mg per kg works, there is no reason to go to 6.
What does caffeine give you?
On average 2 to 4% better endurance performance, according to the same position stand. In a meta-analysis the authors cite, time trial performance improved by 2.3% (± 2.6). That spread is large. Some people benefit a lot, others little or not at all.
What does 2% mean for your goal time? A worked example, not a promise: 2% of 75 minutes is 1.5 minutes. That is an average from endurance studies, not a HYROX measurement. The ISSN paper is about sport in general; this source includes no HYROX study.
The downside is in there too. Caffeine can disturb your sleep and make you restless. If you start in an afternoon wave, you take the dose later in the day and your sleep that night is closer to when you took it.
When do you take caffeine on race day?
Usually about 60 minutes before the start. On race day that is harder than in training, because your start time is fixed per wave and your waiting time after check-in varies. Count back from your start time, not from the moment you arrive at the venue.
If your start time comes right after a long queue, take your dose a little too early rather than on the start line. That is a practical choice of ours; the ISSN only gives the roughly 60 minutes.
Should you take carbohydrates during the race?
For a race around 1:15 there is no fixed number. Jeukendrup (2014) groups efforts by duration. For about 30 minutes to 1 hour, a carbohydrate mouth rinse may be enough: you briefly swill a sports drink around your mouth. For 2 to 3 hours he gives about 60 g per hour, for longer efforts about 90 g per hour.
A race of 75 minutes falls between those first two groups. That is why we don't give a fixed number of grams per hour. A sip of sports drink in the Roxzone, if you tolerate it well in training, is in line with the mouth rinse from the review.
A caveat on this source: it is a review with mostly research in trained endurance athletes. It is not about HYROX. The race consists of 8 × 1 km of running and 8 stations, and drinking on the stations is not easy.
How hard is the race on your body?
Hard. Brandt and colleagues (2025) measured in a simulated race with 11 recreational athletes an average heart rate of 170.9 beats per minute and lactate of 6.3 mmol/l on average, with a peak of 8.5 mmol/l at the wall balls. They spent 79.5% of the time in the "very hard" category. Eleven people in a simulation is a small group, but at that load you don't eat in a relaxed way along the way.
That is why we keep the meal beforehand light. Something you often eat in training, with enough time to let it settle. How many hours that is for you, you test in a sim. We don't give a fixed standard for the pre-race meal here; our sources have no number for it.
How do you test this beforehand?
In a sim, as close to race day as possible. Take your caffeine at the same time as on race day, eat the same meal and drink the same in the Roxzone. Pay attention to your stomach during the burpee broad jumps and the wall balls, and to your sleep that night. How to build a sim is in build a HYROX simulation.
Don't leave that test until your taper week. In HYROX taper you can read why the last two weeks are for recovery and not for new things. Caffeine also won't help you if you run run 1 too hard. You work out your pace per run in run pacing.
What does race day look like?
Like this, if you have tested everything in training. The times are relative to your own start wave.
| Moment | What you do | Why |
|---|---|---|
| Evening before | Normal meal you know, no experiments | Race day brings enough new things already |
| Morning | Breakfast you tolerate well in training | Time to digest before the warm-up |
| A few hours before the start | Light meal or snack, same as in your sim | What you tested in the sim |
| About 60 min before the start | Caffeine: 3 to 6 mg/kg (at 70 kg 210 to 420 mg, at 80 kg 240 to 480 mg) | Guest et al. (2021) |
| Warm-up | Small sips of water or sports drink | Stand at the start feeling comfortable |
| During the race | Possibly a sip of sports drink or a mouth rinse in the Roxzone | Jeukendrup (2014), for 30 min to 1 hour |
| After the finish | Eat and drink what you like | Recovery starts, the race is done |
Going to Amsterdam? See HYROX Amsterdam preparation for how the day works in practice. Your plan for the weeks before is in the HYROX training plan.
When should you be careful?
With health problems, heart symptoms, medication or pregnancy. Talk to a doctor first before you use caffeine to perform. If you know you sleep badly or get restless quickly from coffee, a low dose or no caffeine is a perfectly good choice too. The numbers in this guide are averages from research, not personal nutrition advice.
How Benchmrk does it
The app does not plan your nutrition. The plan does give you sims and a 2-week taper, so you can test caffeine, breakfast and drinking in the Roxzone in time. You log pace, heart rate and RPE, and the plan adapts to what you log. Your prediction per run, station and Roxzone shows which pace fits your goal time.
Frequently asked questions
How much caffeine should you take before a HYROX race?
The ISSN gives 3 to 6 mg per kg of body weight. For 70 kg that is 210 to 420 mg, for 80 kg 240 to 480 mg. Start at the low end and test it in training first.
When do you take caffeine before the start?
Usually about 60 minutes beforehand, according to the ISSN position stand. Allow for the time between check-in and your start wave.
Should you eat during a HYROX race?
There is no fixed number for a race of about 75 minutes. Jeukendrup (2014) writes that for efforts of about 30 minutes to 1 hour a carbohydrate mouth rinse may be enough. Test in a sim what your stomach tolerates.
Does more caffeine work better?
According to the ISSN, 9 mg per kg is not necessary, and an effect is possible from 2 mg per kg. More caffeine means a higher chance of restlessness and poor sleep.
Can everyone use caffeine before a race?
No. If you have heart problems or other health issues, take medication or are pregnant, talk to a doctor first. This is general information, not medical advice.
Sources
- Guest NS et al. (2021). International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition 18:1 (accessed on 13 November 2026)
- Jeukendrup A (2014). A Step Towards Personalized Sports Nutrition: Carbohydrate Intake During Exercise. Sports Medicine 44 Suppl 1:25–33 (accessed on 13 November 2026)
- Brandt et al. (2025), Acute physiological responses and performance determinants in Hyrox©, Frontiers in Physiology (accessed on 13 November 2026)
- HYROX – The Fitness Race (accessed on 13 November 2026)