Long-Distance Open Water Fueling: Practical Strategies for Energy Gels and Salt Tablets

Introduction

Open-water long-distance races range from 3 km to 5 km or even 10 km, often taking over 1 to 3 hours. Unlike swimming in a pool, athletes cannot stop at the wall to drink or rest; all fueling must be done entirely in the water. Many swimmers attempting long distances for the first time experience muscle cramps, mental fog, or even hypoglycemia symptoms in the latter half of the race. Establishing a proper fueling strategy is one of the keys to completing a long-distance race.

Assessing Energy Needs

Swimming is a full-body aerobic exercise, and calorie expenditure varies with water temperature and intensity. In 20°C water, a 65 kg athlete burns approximately 500 to 700 kcal per hour. The colder the water, the higher the expenditure as the body works to maintain core temperature. Beyond 60 minutes of aerobic exercise, glycogen stores begin to decline noticeably; without timely carbohydrate supplementation, pace will drop significantly in the latter stages.

Choosing and Carrying Energy Gels

There is a wide variety of energy gels on the market. For long-distance open-water events, products with the following characteristics are recommended:

• Electrolyte formula: Replenishes sodium and potassium simultaneously, reducing the need to carry separate salt tablets
• Moderate consistency: When fueling in the water, gels that are too thin can easily be washed away or inhaled, while those too thick are hard to swallow
• Easy-tear packaging: Must be openable quickly with one hand while wearing silicone gloves or with wet fingers
• Refreshing flavor: In a seawater environment, overly sweet flavors can trigger nausea

There are several common ways to carry gels. The most common is to tuck energy gels into a waterproof waist belt or clip them to the collar of a wetsuit, secured with safety pins before the race. Some athletes use a small fueling pouch strapped to the arm for easy one-handed access. Another option is to place fuel in the storage compartment of a tow buoy (such as a Swim Secure tow float), but be mindful of how smoothly you can retrieve it so as not to disrupt your swimming rhythm.

When fueling in the water, first switch to a backstroke or treading-water position, stabilize your head, then tear open the gel, take small sips, and immediately follow with a few sips of water (if the race has aid stations) or naturally clear your mouth.

The Role and Timing of Salt Tablets

Prolonged swimming causes heavy sweating (yes, swimmers sweat too), and combined with osmotic sodium loss through the skin in a seawater environment, the risk of electrolyte imbalance cannot be ignored. Hyponatremia has occurred in ultra-distance swimming races, with symptoms including headache, nausea, confusion, and in severe cases, life-threatening conditions.

Salt tablets typically contain 250–500 mg of sodium chloride per tablet, along with potassium and magnesium. Recommended timing:

• Replenish every 45–60 minutes (adjust based on individual sweat rate)
• When water temperature is below 22°C, start supplementation earlier due to greater energy expenditure
• Take immediately when you feel the onset of mild cramping

Salt tablets are carried similarly to energy gels—placed in a small waterproof pill container and stored in a waist belt.

Fueling Timelines and Training

A fueling strategy cannot be improvised on race day; it must be rehearsed repeatedly in training. In every long-distance session exceeding 90 minutes, simulate the actual fueling process so that the muscle memory of retrieving fuel becomes automatic, while also testing your stomach’s tolerance for different energy gel brands.

Some athletes prefer to do a few side-lying kicks before and after a fueling point to stabilize their body before consuming fuel. Finding the fueling rhythm that works best for you is more important than copying someone else’s strategy.

Practical Tips

• Two days before the race, confirm that all fuel has been tested in training; never try new products on race day
• Seal-test your fueling pouch: submerge it in hot water to confirm waterproofing
• If the race has aid stations, learn their locations and what they offer in advance (usually bananas, energy jelly)
• Set fueling cues: time your intake by fixed distances (e.g., every 1 km) rather than checking your watch, which is more intuitive
• Increase carbohydrate intake (carbo-loading) the day before a long race to reduce fueling pressure during the event

Conclusion

Long-distance open-water swimming tests not only physical endurance but also a fine-tuned awareness of your body’s needs and meticulous planning. Energy gels and salt tablets are supporting tools; the true foundation remains solid training and an understanding of your own metabolism. Starting with your next long-distance session, bring your fuel and rehearse your own fueling ritual in the water.

Related Reading

• Open-Water Energy Fueling: How to Eat During Long-Distance Swim Races
• Open-Water Fueling Strategies: Energy Supplementation for Long-Distance Sea Swims
• Fueling Strategies for Long-Distance Swimming: Pool Fueling vs. Open-Water Fueling Differences
• Trail Fueling: The Best Combination of Energy Gels, Salt Tablets, and Solid Food