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Energy gels
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How to fuel your long-distance swim, plus energy gels tried and tested

Swimming in open water poses unique challenges in terms of energy needs. Read our tips for staying fuelled on long-distance swims, plus our guide to the best energy gels.

Here we share expert advice on how to fuel your long-distance swim from Performance Director at TORQ Marcus Willday, marathon swimmer Sarah Thomas and Outdoor Swimmer founder Simon Griffiths. Nutrition becomes more significant in longer events and we recommend you do extra research.

How to fuel your long distance-swim

It’s all about the carbs

When you exercise at high intensity, your body’s primary source of fuel is carbohydrate. At the beginning of an exercise session, this carbohydrate will mostly come from glycogen, stored in your muscles and liver.

Roughly speaking, as long as you have eaten recently and sensibly, these stores will last for around 90 to 120 minutes before becoming depleted to such a level that your performance suffers. To continue swimming at high intensity, you need to eat or drink something with more carbohydrate.

Energy gels are a convenient – but not the only – way to do this. They are usually supplied in waterproof sachets that are easy to carry (such as inside your costume or the sleeve of your wetsuit) and quick to consume. Solid food, on the other hand, can take too long to chew – and if you’ve ever tried chewing while swimming, you’ll know it isn’t easy.

Why do swimmers use energy gels?

Swimming presents a unique set of nutritional challenges compared to land-based endurance sports such as triathlon. “The practical ability to carry and consume carbohydrate rich foods to offset the threat of carbohydrate depletion is considerably difficult, requiring the swimmer to significantly reduce pace, or even come to a complete stop,” says Marcus Willday, Performance Director at TORQ.

When racing or swimming long distances, energy gels provide a highly concentrated source of carbohydrate in a format that maximises its delivery. Take TORQ’s energy gels: a 45g sachet contains around 30g of carbohydrate containing the glucose derivative maltodextrin (for rapid absorption) and fructose, helping to maximise carbohydrate delivery and improve stomach comfort.

When to use energy gels

For events or training sessions lasting less than one hour, you should not need anything. For an event lasting up to two hours, 30-60g of carbohydrate per hour should be sufficient. For longer events, the guidelines typically suggest 60-90g per hour, but note that your stomach may struggle with these higher amounts. Keep in mind that when swimming, it’s hard to completely empty a sachet, so you will get fewer carbs than advertised. Also, note that these are the amounts required for high intensity exercise such as racing; you will need less at lower intensities.

What else to look for in an energy gel

For swimmers, key considerations are packaging (is it easy to open in the water), carbs per serving, and the taste, which can be very personal. In terms of the packaging, we like the sachets where the top is not completely removed; we don’t like to leave litter in the water and those tear-off tops are easy to drop. Bear in mind, too, many gels are intended to be taken with water and this may not be possible in some swimming scenarios.

How to stay hydrated

When you sweat, you lose electrolytes as well as water, which is why most sports drinks contain electrolytes. Drinking only water while exercising in hot conditions can result in hyponatremia – when the sodium level in your blood is too low. Including electrolytes may help prevent this. However, the situation in swimming is complex because your body is often being cooled by the water (so you sweat less), you may be accidentally swallowing salty sea water, and you probably drink less than you would while running or cycling. For gels that don’t have electrolytes, you may want to take them with an electrolyte drink.

What are the benefits of caffeine?

Some energy gels offer a secondary boost by adding caffeine, but it doesn’t suit everyone. If you want to use it in an event, test it in training first and monitor your intake. To put it in context, a single caffeinated TORQ gel has 89mg of caffeine, compared with 75mg in a Starbucks single espresso shot. “Caffeine is typically consumed during the latter stages of a swim session, when fatigue is starting to occur,” says Marcus. “Caffeine can help to reduce the rate of perceived exertion while also increasing alertness and improving decision making.”

What happens if your body doesn’t have the right fuel?

If fuelling and hydration are neglected, you will soon feel the effects and your performance will be impacted. When meeting your body’s carbohydrate needs, consistency is key. “In order to sustain your energy and effort for long swims, you need to fuel consistently and avoid major ups and downs in calories and nutrition,” says marathon swimmer Sarah Thomas. “Having a good calorie intake keeps you fuelled and warm. If you crash and aren’t fuelling properly, you’ll end up super sore and depleted at the end, or even be forced to abandon your swim.”

Find a routine that works for you

Practice makes perfect, and this is definitely the case when finding out what works for your body. “Everybody is different and we all react differently to certain products. Use your training swims to practice your nutrition, logging how you feel before and after and noting your recovery the following day,” says Sarah. “Follow your intuition; just because something works for me doesn’t mean it will work for you!”

Sarah also suggests keeping it simple, and having a clear, easy to follow plan written down in advance. After all, on very long swims it will be your crew who will manage your feeds. “Ask yourself: ‘How are they going to give this to me from a boat?’ Sandwiches are a nightmare, they get soggy. Small things can be hard to grasp if your hands are cold. So, plan ahead and practice.”

The best nutrition gels for fuelling your swims

The best for natural flavours | Veloforte, £6.59 (pack of 3)
The best range of flavours | TORQ, £12.50 (pack of 6)
The best all-rounder | Elivar SUSTAIN GO!, £24.99 (pack of 12)

Energy gels


£6.59 (pack of 3)

They say: Delivering nature’s power at pace, this mixed pack of break-through silky-smooth natural gels gives you the ultimate in flavour and performance versatility from zingy to savoury, fruity to richly mellow to keep your training, competing or active lifestyle energised, motivated and focused. Optimally balanced with dual-source carbohydrates and the purest electrolytes, they’re designed to give you the confidence you need to perform at your best, naturally.

We say: You can get fed up with overly sweet fruity flavours. The Veloforte range offers something a little different. Flavours include Tempo (dates, lemon and ginger), Doppia (maple, coffee and guarana with 75mg caffeine) and Desto (tart cherry and guarana with 75mg caffeine). The Primo flavour, a blend of beetroot and lemon, in particular, made an interesting change. Our tester liked it but it may not be to everyone’s taste. Overall, the flavours are authentic, which you’d expect with all natural ingredients.

Energy gels


£5.99 (pack of 2)

They say: At VALA, we believe in the power of nature to fuel up athletes of all sports. That’s why we use 100% natural ingredients in our energy gels: maple syrup, date paste, chia seeds, lemon juice, lime juice, matcha tea powder and Halen Môn sea salt. We don’t use hidden preservatives or additives – what you see on our label is exactly what you get. We’re proud to be creators of an energy gel that you can actually look forward to eating every time you train and race!

We say: Despite – or perhaps because of – the slightly gritty texture, this one went down well. It’s perhaps more paste than gel, and tastes naturally sweet without being sickly. The lemon and lime juice adds a fresh aftertaste that works well to counteract the excessive sweetness you sometimes find in some energy gels. Overall, we were very impressed.

Energy gels


£12.50 (pack of 6)

They say: TORQ Gel is a naturally flavoured high-potency hypertonic energy gel, containing no artificial sweeteners or colours, with a silky smooth melt-in-the-mouth texture. This product has been carefully formulated to deliver TORQ’s unique blend of multiple-transportable carbohydrates and electrolytes to the working muscles extremely quickly and efficiently using research-proven 2:1 Maltodextrin:Fructose technology and all five key electrolytes.

We say: A wide range of interesting flavours such as apple crumble, strawberry yoghurt and cherry bakewell help guard against taste fatigue. The gels can feel a little heavy to swallow but sometimes that’s exactly what you want. We think they are best taken with a drink of water. They are also easier to open than some other brands, which makes it handy for in-water use, and have a litter-free tab so you don’t have to worry about polluting the environment once you’ve consumed the gel.

Energy gels


£6.39 (pack of 3)

They say: Our gels are clean energy, made from real fruit juices, coconut sugar and natural brown rice syrup. Designed to be more gentle on the stomach than others, whilst stoking your furnace with a fast-absorbing energy source for sustained efforts. You’ll never see Maltodextrin or Stevia in our products, and there’s no need for stabilisers and acidity regulators.

We say: Lighter in consistency than some of the other gels we tested, these go down well, and are easy on the stomach. These have fewer carbohydrates as a percentage of total volume than the others we tried, which means they can be taken without water, making them convenient for swimming – but note they are not a hydration product and you still need to drink. Other flavours include passionfruit and coconut, and blueberry and hibiscus. with caffeine.

Energy gels


£24.99 (pack of 12)

They say: SUSTAIN GO! is a unique blend of fast and slow release carbs to deliver a sustained release of energy. It helps avoid the darker downsides of traditional high sugar gels including blood sugar spikes, reduced fat mobilisation, stomach upset and bloating. Each SUSTAIN GO! gel includes 40 mg of Ubiquinol, the active form of Co-Enzyme Q10 which enables the energy production process that converts food into energy in our cells.

We say: While the carbohydrates dose is mid-range (around 25g per serving) the sachet volume is larger than most of the gels we tested, which makes this energy gel easier to take if you don’t have water to hand – a surprisingly common occurrence when open water swimming! We liked the simple flavours, which also includes lemon and orange and forest fruit.

Energy gels

Precision Hydration

£8.99 (pack of 4)

They say: The most efficient way to get 30g of carbohydrate into your system fast. Our gels have a very mild, neutral taste reducing flavour fatigue during longer efforts. The texture is designed to reduce stickiness in the mouth and minimise the need to wash them down with fluid immediately.

We say: We liked the carbs and nothing else approach. We also like that the tab stays attached when you open the sachet, making it much less likely that you will drop it and create litter. The neutral flavour is fine, moderately sweet but neutral. We found that the caffeinated version has a slightly bitter aftertaste – but 100mg of caffeine did give quite a kick.

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