Long distance swimming, particularly in open water, is an extreme endurance event that requires a meticulously planned nutritional strategy. Unlike land-based sports, consuming calories and staying hydrated while in the water presents unique challenges, making it essential to train your gut just as you train your muscles. A successful fuelling plan can mean the difference between a strong finish and 'hitting the wall'.
Pre-Swim Fuelling: The Foundation for Success
Proper fuelling begins well before you enter the water, with strategies to maximize your body's glycogen stores. Glycogen, a stored form of carbohydrate in your muscles and liver, is the primary fuel source for high-intensity exercise. Without adequate stores, your performance will suffer in as little as 90 minutes.
The Night Before
Your evening meal before a big swim should focus on high-carbohydrate foods to top off your energy reserves. This is not the time for heavy, high-fat, or high-fiber foods, which can cause digestive discomfort.
- Ideal dinner options include:
- Pasta with a light, tomato-based sauce
- Rice dishes with lean chicken or fish
- Baked potatoes
Race Morning
Your final pre-swim meal should be consumed 2–4 hours before your event to allow for proper digestion. This meal should also be rich in carbohydrates, with a moderate amount of protein and low in fat and fiber.
- Recommended breakfast foods:
- Oatmeal with fruit
- Toast with jam or honey
- A bagel with a small amount of peanut butter
Final Top-Up
Approximately 15-30 minutes before the start, have a small, easily digestible carbohydrate snack to top off your blood sugar levels. An energy gel, a handful of raisins, or an electrolyte drink can provide this quick boost without upsetting your stomach. This is also the ideal time to consider a caffeinated gel if you are accustomed to it, as caffeine can improve focus and endurance.
Fuelling and Hydrating During the Swim
For any swim lasting over 90 minutes, in-water fueling is non-negotiable. The most effective strategy involves consuming easily digestible carbohydrates and electrolytes from liquids or gels. Solid food, while sometimes used for ultra-distances, is often too difficult to chew and digest, especially in colder water.
Choosing Your Fuel: Liquids vs. Gels vs. Solids
Marathon swimmers use a variety of fuel sources, but their preference often comes down to ease of consumption and stomach tolerance. Practice is key to finding what works for you.
| Fuel Type | Carbohydrates | Ease of Consumption | Common Examples |
|---|---|---|---|
| Sports Drinks | 6-8% solution; approx. 15-25g carbs/250ml | Very Easy (sips) | Gatorade, warm carbohydrate-electrolyte drinks |
| Energy Gels | Highly concentrated; approx. 20-30g carbs/sachet | Very Easy (squeeze) | SIS Isotonic Gels, GU Gels |
| Energy Chews | Concentrated; approx. 30g carbs/serving | Easy to Moderate (chew) | Gatorade Chews, Clif Bloks |
| Soft Solids | Variable; often a mix of carbs, protein, fat | Difficult (chewing) | Canned peaches, small banana pieces |
Hydration Beyond the Thirst
It's easy to overlook hydration in the water because the cooling effect masks sweat. However, dehydration of just 2% of your body weight can significantly impact performance. For swims over an hour, a sports drink with electrolytes is superior to water alone for maintaining fluid balance and preventing cramping.
- Strategic hydration tips:
- Pre-load: Drink a strong electrolyte solution (~500ml) 60-90 minutes before your swim to increase blood plasma volume and start with a hydration advantage.
- In-swim: Consume approximately 200–300ml of a sports drink every 20-30 minutes during longer swims. For multi-hour events, target 60-90g of carbs per hour.
- Electrolytes: Sodium is crucial for fluid absorption. In addition to sports drinks, some swimmers use salt tablets or warm broth, especially in cold water.
Post-Swim Recovery: The Final Stage of Fueling
Once you exit the water, your fueling job is not over. The recovery phase is essential for replenishing glycogen stores and repairing muscle tissue. The 30-60 minute window immediately after your swim is a prime time for nutrient absorption.
Your recovery meal or snack should contain a 3:1 ratio of carbohydrates to protein.
- Quick recovery options include:
- Chocolate milk
- Protein shake with fruit
- Greek yogurt with berries and granola
Following this initial refuel, consume a balanced meal within a couple of hours. This meal should include complex carbohydrates, lean protein, and healthy fats, such as a salmon and sweet potato stir-fry. Remember to continue rehydrating, aiming to replace 150% of the fluid lost during the swim.
Practice Makes Perfect
The final, and perhaps most crucial, element of a successful long-distance fueling plan is practice. You must train your gut to handle the fluids and calories you plan to consume on race day. This means testing different products, timings, and quantities during your training swims. What works for one athlete may cause another significant gastrointestinal distress. Always test new nutritional products and strategies in training, never during a key race. Experiment with your race-day nutrition during long training sessions to build confidence and ensure your body is prepared for the challenge ahead. For more information on training nutrition, visit the US Masters Swimming website.
