Planning your strategy for ultra-distance events can be tricky as you attempt to predict how your body will react to the conditions, as well as your food and fluid intake, during the many (many, many) hours out on course.

Experience helps you become attuned to your body’s needs in events of varying lengths and intensities over time, so it's important to ‘practice what you race' by testing your nutrition and hydration strategies - while also building some flexibility into those plans - during training...


Pre-race hydration: Starting hydrated

Most people are aware of the concept of ‘carb-loading’ before a big race, particularly for ultra distances but, when it comes to hydration, things aren't always as clear cut.

There's a danger of athletes thinking that they need to gulp lots of plain water down in the build-up to an event, which can lead to a race-ruining (and potentially dangerous) condition known as hyponatremia.

Instead, drinking a strong electrolyte drink before a race –  often referred to as ‘preloading’ – can significantly improve your performance and it’s a topic we’ve covered in detail in our blog: How to start hydrated and why that’s so important.

It’s worth trialling the following protocol during your tougher training sessions ahead of your next ultra-distance race as you look to give yourself a bigger reserve of fluids and electrolytes to draw upon once the real business of running (and sweating) starts:

  • Drink 1 x PH 1500 mixed with ~500ml (16oz) of water the evening before the race/training session
  • Drink 1 x PH 1500 mixed with ~500ml (16oz) of water ~90 minutes before the start (Aim to finish your drink around 45 minutes before you start to allow time for your body to absorb. And drink the electrolytes in water you’d have drunk anyway so you don’t overdo it)

Why preload?

It’ll help your cardiovascular system cool you down and deliver oxygen to your working muscles. This reduces fatigue and enables you to maintain your performance for longer.

Ultimately, making sure you get it right before you start is what you'd call 'free money' in the ultra-distance game!

Image Credit: Alex Croucher ©

Pre-race nutrition: Carb-loading

You’re probably familiar with the idea of carb-loading, which involves maximising the amount of glycogen you have stored in your muscles and liver before a strenuous activity.

There’s still plenty of debate over what, when and how you should eat, but eating added carbohydrates in the days leading up to the race provides yet more free money (we’re rich!) as you’re storing up energy for your body to use during your upcoming ultra event.

A study by Tiller et al. (2019) suggests carb availability for racing can be maximised by adhering to a loading strategy of around 10g of carbs per kg of athlete weight in the 48 hours leading into the event.

A few of the ultra athletes we’ve spoken to prefer to carb-load a few days before their event and might consider a fairly large breakfast on the morning of the race. Some examples of their pre-race breakfasts include:

  • Light style cereal or oats/porridge with fruit
  • Toast + piece of fruit
  • Toasted sandwich
  • Rice cakes with peanut butter + banana

During a recent appearance on the Science of Ultra podcast, Dr Asker Jeukendrup recommended a high carb intake (of ~200g carbs) around 3-4 hours before the start and then begin 'race fuelling' (e.g. 25g of carbs through a gel) just before the event gets underway.

Which brings us nicely to hydration and fuelling during the race…

During a race: hydration

A race lasting longer than 4 hours is too long to go without drinking, so you’ll need to take on some fluids and electrolytes.

As a rule of thumb, most athletes will probably need to take in between 500ml-1L (16oz-32oz) of fluids per hour during an ultra race, but the exact amount will depend on factors such as the conditions, your own sweat rate and past experiences.

Ultimately, you’re not aiming for 100% like-for-like replacement as this can be counter-productive.

Experimenting within these guidelines in training, while learning to listen to your body, is the best way to work out how much you need to drink during a race. 

Image Credit: ÖtillÖ/Pierre Mangez ©

If you’re carrying your own fluids, consider carrying 1 bottle of plain water and 1 bottle of pre-mixed electrolytes, and sip between the two according to your sense of taste and thirst.

Ultra athletes we've worked with have found taking a bottle of plain water for every 2-3 bottles of PH they drink during longer races generally provides a good ratio.

Unless you’re doing an unsupported event, you’ll be able to top up your bottles at aid stations, so you can carry your electrolytes with you and mix with water when you stop.

Alternatively, carry SweatSalt capsules and swallow them with plain water (1 capsule with ~500ml (16oz) of water is equivalent to a PH 500 strength drink, 2 capsules per 500ml is the equivalent of PH 1000 etc).

Sodium intake (along with appropriate amounts of fluid) becomes far more important during ultra distance events because the risk of hyponatremia increases along with total sweat losses.

So, it’s more important than ever to be getting an appropriate level of electrolytes in with your drinks. It will be worth testing your hydration strategy in training and try race simulation sessions.

We generally advocate keeping your fluids for hydration and your gels & solids for fuelling. If you find you're able to mix your electrolyte and carbohydrate drink without any issues, then crack on, but if you do have problems then it might be worth checking out this blog: Should you combine your carbohydrate and electrolyte drinks?

During a race: nutrition

A study found that 96% of athletes competing in the 100-mile Western States Endurance Run experienced GI symptoms, with 44% indicating that GI issues negatively impacted race performance.

To help limit potential GI issues, test your nutrition strategy in order to see how your body reacts to and digests different ‘fuel’ sources.

Like hydration, 100% like-for-like replacement of nutrition losses isn’t realistic because of the duration of ultra events and it’s not feasible to meet caloric demands in their entirety.

But, how much should you be replacing?

It’s generally recognised that the optimal carb consumption for athletes racing long distances is around 60-90g per hour, but there will obviously be individual differences between athletes.

It’s important to know that you can mix and match your carbohydrate sources and use drinks, gels, chews and bars depending on your personal preferences. Train over and over again before you show up on race day – practice before you race it.

If you can, see what the aid stations on the course are going to be serving up and check where the aid stations are positioned, so you know what you’ll need to carry and what you can pick up.


Image Credit: Jake Baggaley ©

Which foods to choose?

Andy has outlined the sources of fuel he’s used in a previous blog - How PH fits in with your wider nutrition plan - and Abby analysed Andy & JP's nutrition and hydration strategies for their 9-hour race at the ÖtillÖ Swimrun World Championship.

There was plenty of variation in what the lads ate and the value of having options shouldn’t be underestimated - the thought of gloopy gels for hours and hours on end isn’t particularly appealing as the taste becomes tiresome and your stomach starts to feel empty.

And you’re likely to find that your tastes change throughout the course of the event (for example, Andy finds he craves saltier foods when racing 6+ hours).

Here are some potential ideas for sources of carbohydrates when you’re putting your nutrition plan together:


  • Most = ~20-25g, but some = ~35-40g
  • Maurten 100 gels = ~ 25g carb per gel

Bars and "bites"

  • A choc-chip Clif Bar = ~45g
  • A Go Faster Foods Go Bite = 6.7g
  • Luchos Dillitos Bocadillos = 22.5g
  • Clif Bloks - A chew rather than a gel. 4 Bloks = 32g

Other ideas:

  • 1 banana = ~27g of carbs
  • Jelly Babies. 8 sweets = ~42g
  • Dehydrated berries, smashed berries, peanut butter and jelly sandwiches, potatoes, sweet potatoes, rice cakes

Image Credit: Jonny Tye ©


Most runners will finish a race dehydrated to some extent and you’ll need to replenish your losses before you’re ready to go again.

Most of the time, just drinking water and eating as normal after the race is enough, but if you’re suffering with cramp, feel especially fatigued or you plan to train/race soon after your race, then you might need to be a bit more aggressive and consider drinking a strong electrolyte drink in the first few hours after you’ve finished your race.

Your recovery will depend on when you’re next hoping to perform at your best. 

According to Dr Jeukendrup, a more aggressive strategy for replacing carbs would aim for around 60-70g of carbs in the hour after finishing your event. Continue to eat for roughly intervals of one-hour for the first three hours, which should take you to your next larger meal.

Ultimately, how you approach pre-, during and post-race hydration and nutrition will be individual to you as an athlete. 

Put strategies in place and use them as guard rails, but ensure you have the flexibility to react to your body’s changing needs during the course of race day.