Hydration and fuelling isn't something that immediately comes to mind when thinking about swimming because eating and drinking isn't something we tend to do when we're actually in the water. (Unless you're yet to perfect your technique and you're taking in plenty of lovely sea/river water...).

But starting well fuelled and hydrated is crucial to performing at your best, particularly during longer swims.

It's obvious that you'll be burning energy during your swim but, whilst you might not notice it, you'll also be sweating too. And, because you're not usually in a position to replace those fluid/electrolyte losses when you're in the water, it's extra important to start fully topped up.

Here's some advice to help you nail your approach to pre-swim fuelling and hydration...

1 mile / 1.9km

Before the race

Fuel

What to do

  • Aim to carb load in the day or two before your event, to top off your stored energy (glycogen) levels
  • Eat an energy gel (such as the PF 30 Gel) in the final 15 mins or so before you start. This'll provide additional fuel to be utilised in the early stages and increase your focus and energy levels

Why?

  • Carb-loading is a well-known tactic used by endurance athletes
  • Think of your glycogen stores as the fuel you have in the tank before a long journey. The more you start with, the longer you can keep going before you need to top-up
  • Simple carbs taken in the last 15 mins will hit your bloodstream around the start of the race, increasing energy availability just as energy use is ramping up in your body

Hydration

What to do

  • Your race pack will include a packet of our strongest electrolyte drink, PH 1500
  • Mix it into 500ml of water and aim to drink it about ~60-90 mins before you start
  • This is known as ‘preloading’ and it can significantly improve your performance
  • Finish your drink ~45 mins before you start to allow your gut to absorb it
  • Drink the electrolytes in water you’d have drunk anyway so you don’t overdo it
  • DON’T just drink lots of water before a race! You can end up diluting your blood sodium levels, increasing the risk of a race-ruining condition called hyponatremia (low blood sodium levels)

Why?

  • It’ll boost your blood volume, a proven way to enhance performance during intense exercise, especially in the heat
  • 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
  • PH 1500 electrolyte drink is a very effective preloader as it contains 3x more sodium than typical sports drinks
  • Preloading may also help you avoid cramp, which can be triggered by sodium depletion

Want to bring some of your own fuel and electrolytes?

Grab a Castle Race Series Taster Pack. Don't forget to use the 15% off code you can find in emails from Castle Race Series.

Questions?

Book a free one-to-one video call with one of our fuelling experts or email hello@pfandh.com.

2.5km / 3.8km / 5km

Before the race

Fuel

What to do

  • Aim to carb load in the day or two before your event, to top off your stored energy (glycogen) levels
  • Eat an energy gel (such as the PF 30 Gel) in the final 15 mins or so before you start. This'll provide additional fuel to be utilised in the early stages and increase your focus and energy levels

Why?

  • Carb-loading is a well-known tactic used by endurance athletes
  • Think of your glycogen stores as the fuel you have in the tank before a long journey. The more you start with, the longer you can keep going before you need to top-up
  • Simple carbs taken in the last 15 mins will hit your bloodstream around the start of the race, increasing energy availability just as energy use is ramping up in your body

Hydration

What to do

  • Your race pack will include a packet of our strongest electrolyte drink, PH 1500
  • Mix it into 500ml of water and aim to drink it about ~60-90 mins before you start
  • This is known as ‘preloading’ and it can significantly improve your performance
  • Finish your drink ~45 mins before you start to allow your gut to absorb it
  • Drink the electrolytes in water you’d have drunk anyway so you don’t overdo it
  • DON’T just drink lots of water before a race! You can end up diluting your blood sodium levels, increasing the risk of a race-ruining condition called hyponatremia (low blood sodium levels)

Why?

  • It’ll boost your blood volume, a proven way to enhance performance during intense exercise, especially in the heat
  • 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
  • PH 1500 electrolyte drink is a very effective preloader as it contains 3x more sodium than typical sports drinks
  • Preloading may also help you avoid cramp, which can be triggered by sodium depletion

Want to bring some of your own fuel and electrolytes?

Grab a Castle Race Series Taster Pack. Don't forget to use the 15% off code you can find in emails from Castle Race Series.

Questions?

Book a free one-to-one video call with one of our fuelling experts or email hello@pfandh.com.

10km

Before the race

Fuel

What to do

  • Aim to carb load in the day or two before your event, to top off your stored energy (glycogen) levels
  • Eat an energy gel (such as the PF 30 Gel) in the final 15 mins or so before you start. This'll provide additional fuel to be utilised in the early stages and increase your focus and energy levels

Why?

  • Carb-loading is a well-known tactic used by endurance athletes
  • Think of your glycogen stores as the fuel you have in the tank before a long journey. The more you start with, the longer you can keep going before you need to top-up
  • Simple carbs taken in the last 15 mins will hit your bloodstream around the start of the race, increasing energy availability just as energy use is ramping up in your body

Hydration

What to do

  • Your race pack will include a packet of our strongest electrolyte drink, PH 1500
  • Mix it into 500ml of water and aim to drink it about ~60-90 mins before you start
  • This is known as ‘preloading’ and it can significantly improve your performance
  • Finish your drink ~45 mins before you start to allow your gut to absorb it
  • Drink the electrolytes in water you’d have drunk anyway so you don’t overdo it
  • DON’T just drink lots of water before a race! You can end up diluting your blood sodium levels, increasing the risk of a race-ruining condition called hyponatremia (low blood sodium levels)

Why?

  • It’ll boost your blood volume, a proven way to enhance performance during intense exercise, especially in the heat
  • 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
  • PH 1500 electrolyte drink is a very effective preloader as it contains 3x more sodium than typical sports drinks
  • Preloading may also help you avoid cramp, which can be triggered by sodium depletion

During the race

A 10km swim is long enough that you may need to drink - and even potentially eat something - in order to perform at your best.

Here's what'll be available at the feed stations on the 10km course...

Hydration

  • PH 1000, a low-carb electrolyte drink containing 1,000mg of sodium per litre (~2x the sodium found in typical sports drinks)
  • Water

Fuel

  • PF 30 Energy Gels. Each gel contains 30g of carbohydrate
  • A selection of food and drink such as bananas (cut into thirds, about 9g of carb per third), flat coca-cola (about 10g of carb per 100ml) and jelly babies (or similar, about 5g of carb per sweet)

What to do

  • Use our Quick Carb Calculator to get an idea of how much carbohydrate you'll need per hour to perform at your best
  • Some athletes racing a 10km will benefit from higher intakes of 60 to 90 grams of carbohydrate per hour, perhaps even more than 90g, as long as the amount consumed doesn’t cause stomach problems
  • The higher the amount of carbohydrate you’re aiming to ingest, the more crucial ‘training your gut’ in the lead up to your race becomes
  • An hourly intake of ~60-90+ grams per hour is not something all athletes can achieve immediately and it can take a bit of time to build up to this rate of consumption, especially if you’ve been prone to suffering from GI issues in the past

Why

  • When it comes to powering high intensity endurance exercise, carbohydrate is the main source of fuel used by your body
  • Glycogen (stored carbohydrate) is a finite resource. 90-120 minutes of hard activity will generally deplete your stores enough to significantly compromise your performance. So, at some point, taking in carbs is necessary to maintain a high level of performance

Checklist for adjusting your intake

Signs you may need to drink more include:

  • Feeling thirsty/dry mouth
  • Heart rate drifting upwards when compared to power output or effort
  • Tight, twitchy or crampy muscles

Signs you may need to drink less include:

  • Feeling bloated
  • Feeling water ‘sloshing’ in your stomach
  • Peeing too frequently

Signs you may need to increase your energy intake include:

  • Hunger
  • Attitude or mood deteriorating
  • Craving sugar

Signs you may need to decrease your energy intake include:

  • Feeling/being sick
  • Bloating
  • Upset stomach

Try the on-course fuel/hydration in training

"Nothing new on race day" has always been solid advice.

Grab a Castle Race Series Taster Pack to thoroughly road-test the on-course fuel and hydration before your race.

Don't forget to use the 15% off code you can find in emails from Castle Race Series.

Questions?

Book a free one-to-one video call with one of our fuelling experts or email hello@pfandh.com.