How to Properly Fuel Your Swim Workouts

This article is from Monique Ryan, MS, RD, LDN, CSSD, author of Sports Nutrition for Endurance Athletes.

Triathletes frequently experiment with nutrition strategies to optimize their cycling and run workouts, aiming to consume the right amount of fuel, electrolytes, and fluid before and during training for optimal nutrition. By approaching your swim workouts in the same way while adjusting for a few differences, you can get more out of your workouts in the pool and be more prepared for your other sessions, too.

Unfortunately, swim workouts seem to fall at the most inopportune times with regards to meal timing. Pools are often open only in the early morning or late evening hours. The conundrum, then, is how to time meals and snacks around training for the needed fuel boost, as well as keeping your gastrointestinal system placid and peaceful. It’s worth figuring out, because starting a session under-fueled and poorly hydrated could hamper your workout and affect your energy levels for subsequent training sessions that day and even early the next day. This means your nutritional intake around swim workouts should also be considered in the context of the whole day’s training, as well as that specific swim workout.

Early morning swims
Swims that get you up at the break of dawn present one of the most significant fueling challenges. Whether you wake up hungry or not, you require fuel for training. Liver glycogen stores are depleted overnight while we sleep in order to maintain basic cell functioning. Liver glycogen also breaks down and keeps blood sugar levels on an even keel during workouts. Depending on the day’s previous training and diet, you might also be a bit low on muscle glycogen.

With your energy at a low early in the morning, you have to consider what you can tolerate close to a morning swim. Experiment with easily digested foods and fluids. Tea and coffee provide a caffeine boost, and do serve as hydration as well. Juice can also work for both carbohydrate and fluid intake. Aim for 30 to 45 grams of carbohydrates if possible—even 15 grams of carbohydrates is helpful.

Some suggestions include:

8 ounces juice (30 grams carbohydrate)
Energy bar (about 30-40 grams carbohydrate)
1 slice toast with 2 tbsp. jam (45 grams carbohydrate)
½ cup cooked oatmeal with 2 tbsp. honey (45 grams carbohydrate)
8 ounces milk blended with large banana (40 grams carbohydrate)

If you can’t stomach anything prior, or even if you can, plot out a strategy for fueling during the swim. Even if you do stomach a small snack before, fueling during the swim is helpful, as 60 to 90 minute swims burn through stored fuel at a good pace. And while it’s not apparent, you do sweat in the pool, though maybe at about half the rate as during a run.

Just like any other workout, you can pack a sports drink to consume during swim training. Aim for about 30 grams of carbohydrate per hour. If this would result in a fluid overload, a gel or blocks or related semi-solid carbohydrate can work. Experiment to see what works best for you.

Morning swims deserve a full recovery breakfast in preparation for the next workout. Aim for at least 0.5 grams carbohydrate for every pound of weight (1.2 g/kg) and 10 to 20 grams of protein at this recovery meal. Pack breakfast ahead, and also consider a morning snack if this is going to be a heavy training day.

Afternoon and early evening swims
This swim slot presents less of a pre-exercise challenge than any other time. Lunch might simply be the prime fuel for this workout, but it can be topped off with a light snack one to two hours before the swim using similar guidelines to the early morning swim—modest amounts of easily digested carbohydrate. You can also plan in some light fueling during these workouts. Dinner generally is an ample recovery meal after these training sessions.

Late evening swim sessions
When late evening is your swim time you have several options for parceling out food portions. You can have an ample lunch and then a pre-planned snack of about one gram carbohydrate per pound, two to three hours beforehand. An example would be a peanut butter and jam sandwich and a piece of fruit, or a pasta salad with vegetables, or a low fat yogurt mixed with cereal and fruit. Following this meal plan with dinner after a late swim is fine as you’ll need to refuel and will likely be hungry as well.

Depending on your schedule and tolerance, you might want to have a modest sized dinner three hours before your swim, for example, at 5 p.m. for an 8 p.m. or later swim. If this is your choice, a recovery snack after a swim is also suggested.

Back-to-back sessions including a swim
When your swim workouts back up against another triathlon discipline you should not only plan ahead with pre-exercise and recovery fuel, but also consume fuel during the workout. Refueling with a sports drink or gel, blocks or chews can offset the fuel depletion that occurs when the workout is followed by another. Keep sports nutrition products at the end of your lane for easy use between sets. Gels can also be consumed on top of small to modest amounts of a sports drink.

With any back-to-back training sessions, recovery nutrition refueling, and replenishment fluids are essential and should be planned in view of your energy requirements for the entire day.

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See what to eat and when with Sports Nutrition for Endurance Athletes. Ryan demystifies optimum daily nutrition and shows simple steps to make the best decisions about what you eat and drink.

Swimmer photo from Swim Speed Strokes by Sheila Taormina.

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