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by Steph Saullo RDN

July 3, 2017

The best nutrition plan focuses on both training and race day

An open water swim can be daunting but also exhilarating, fulfilling, and fun. To be a successful open water swimmer you must have a nutrition plan. Your nutrition plan should include fuel and hydration supplementation for both your training sessions and for your open water event.

Training Nutrition

Your everyday nutrition is important to meet energy needs and help reduce the risk of illness and injury. Solid nutrition means you eat enough and the basis of your diet consists of fruits and vegetables, lean protein, good fats, whole grains and other carbohydrate-rich foods, and adequate fuel. High-intensity training decreases immune function, so, without a strong base, you run the risk of compromising your health.


To meet the requirements of training, you must consume adequate calories in the form of all macronutrients: carbohydrate, protein, and fat.

Carbohydrates are necessary for endurance events, especially ultralong events, but you can consider training with low-carbohydrate availability to help the body learn to refuel with less. It’s important not to compromise training by neglecting carbohydrates, so only do this during lower-intensity and shorter-duration training sessions.

Don’t forget about protein when you’re strength training to maintain muscle mass, especially if you’re attempting to reduce your weight.


Water joins carbohydrates, fat, minerals, protein, and vitamins to make the six basic nutrients you need. To meet hydration needs, don’t drink all the fluid you need all at once.

Fluid needs vary person to person and depend on the intensity, duration, and frequency of training. The environment you exercise in—including the altitude and temperature— are also important factors.

If you’re not sure how much fluid you require in a day, you can start by taking your weight in pounds and divide it in half to get a target number of ounces to drink per day. However, this is just a starting point. Ideally, you should also determine your sweat rate to ensure adequate hydration is achieved during training and events.

Swimmers often forget about excessive sweating because they’re in the water and don’t feel sweaty. But swimmers do sweat and inadequate hydration and failure to replace electrolytes can be dangerous.

Lumped together with fluid needs are electrolytes. The average athlete loses 1 to 3 liters of sweat per hour. Most of this is water, but sweat also contains the electrolytes sodium, chloride, potassium, magnesium, and calcium. Sodium losses are usually the greatest but can be vary widely between athletes.

There are various electrolyte products on the market that can help you replace losses during your training and events. It’s important to understand how much sodium and other electrolytes these products contain and how to take these products—some are meant to be taken before activity and others should be ingested during activity.

To help you determine your sodium losses, determine if you’re a salty sweater: if your sweat tastes salty, if sweat stings your eyes or burns in any open wounds, or if you have white lines on your skin or clothes after training, then you should include foods that contain sodium throughout the day. Shaking table salt onto your food or eating pretzels, crackers, salted nuts, or canned soup can be helpful.

If you’re unsure how to appropriately replace electrolytes, consult a registered dietitian for advice.


Supplementing deserves its own article, but here are a few supplements that might be worth your time when preparing for and engaging in open water races.

  • Caffeine: Caffeine increases mental alertness and might improve prolonged exercise. Caffeine should be taken 60 minutes before activity, and the effects last 3 to 4 hours. If you’re engaging in a longer event, you might want to consider another dose or half-dose during the event.
  • Creatine: Supplementation with creatine increases your body’s stores, which can enhance strength and power. Creatine supplementation requires time to load the muscles. Some people chose to load with creatine to maximize storage in the body before competition and then cycle off.
  • Beta-alanine: Beta-alanine might help with training volume and aerobic exercise. It needs time to establish itself in the body (usually about four weeks) with a loading phase followed by a maintenance phase. Consistency is key when taking beta-alanine.
  • Beetroot: Beetroot provides nitrates to help with endurance and it can potentially delay fatigue and prolong exertion.
  • Tart cherry juice: Tart cherry juice can help with recovery and muscle soreness. Drinking a mere 8 ounces post-exercise might do the trick.

You should know about any supplements you are considering and how to effectively and safely take them. Obtain them from a reputable source, consult a registered dietitian as needed, and take them prior to race day to ensure you don’t experience any negative effects on the day of your event.

Race Day Nutrition

Don’t ruin the weeks or months of training you put in for your race by not properly fueling your body on race day. Here’s how to put yourself in the perfect position.

Before the Race

If you have 3 or 4 hours before the race, eat a complete meal with at least three food groups and be sure to include a beverage. An hour before the race, eat some fast-digesting carbohydrates, such as fruit or a few handfuls of cereal (one low in fiber), and take in your caffeine if you’re using it. Right before the race (about 15 to 30 minutes), eat additional carbohydrates, such as a box of raisins, and drink 8 to 12 ounces of water.

During the Race

Events longer than a 5K can deplete your glycogen stores. Any race that will take you more than 60 to 90 minutes will require refueling: 150 to 400 calories’ worth of carbohydrates per hour after the first hour. You should divide this across the hour—every 20 to 30 minutes—so you’re not taking in all the calories at one time.

For races lasting longer than 3 hours, you might need protein in addition to carbohydrates. Keep your refueling strategy simple. Consider the time you’ll need to take in this fuel and how you’ll receive it (i.e., a kayaker handing you a bottle of a premixed solution). To avoid losing momentum or getting cold, don’t spend a lot of time floating or treading water on your feed stops. Depending on your sweat rate and plan, include adequate fluid and electrolytes as needed throughout the race.

Gels and chews, powders mixed with water (or juice depending on the concentration of carbohydrate and your tolerance), and wafer snacks are all great carbohydrate options. For those that require protein, consider peanut butter packets or premade shakes.

After the Race

Following a race, grab some food with carbohydrates to replenish glycogen and protein to help enhance muscle protein synthesis. The easiest thing to do is go out, celebrate, and eat a meal. For every pound lost during the event, drink 16 to 20 ounces of fluid.

Celebrations sometimes involve alcohol. Just remember it’ll dehydrate you and can delay rehydration, so prioritize rehydrating first, then drink your celebratory beer.

Avoid Common Mistakes

Unfortunately, swimmers make the same mistakes too often. The good news is that with ample time and sufficient preparation, these tips can help you avoid common blunders.

  • Eat enough.
  • Don’t leave out or skimp on carbohydrate.
  • Don’t depend on race-day nutrition alone; plan your training nutrition.
  • Take the time to recover.
  • Take advantage of taper.
  • Create a solid nutrition foundation that includes plenty of fruits and vegetables in any form (fresh, frozen, or canned); good fats; lean protein; and whole grains.
  • Plan for fueling and refueling during the race and practice.
  • Don’t assume you can apply the same nutrition strategies that others use. Adapt your own, unique nutrition plan.


  • Open Water
  • Health and Nutrition


  • Diets
  • Nutrition
  • Open Water
  • Recovery