If you’re new to open water swimming or haven’t logged swim distances that more closely resemble something a runner might do, the term feeding may be unfamiliar. Like other marine creatures that spend significant time in the water, long distance open water swimmers also must feed, or briefly stop to take in food and/or drink for swims lasting more than one hour. The purpose of feeding in an open water swim is to hydrate and fuel the body for sustained swimming. It also carries significant mental benefits, as feedings are often looked forward to in extremely long swims, as a treat, as a sign of progress, and as a way to interact with others. We’ll take a look at the following four aspects of feedings: Quantity (Calories and Volume), Frequency, Temperature, and Delivery.
Quantity. The amount that should be consumed is determined by the duration and intensity of the swim. A 150-lb man burns an average of 400 calories per hour swimming moderate freestyle, and up to 700 calories per hour swimming vigorous freestyle (these numbers will be higher in colder water). The intensity should be determined by percentage of max heart rate, rather than speed. Adjust that rate based on your weight and intensity, and multiply by projected hours of your swim. This is how much you will burn, not how much you must consume. The body already stores enough glycogen (sugars, which equals energy) to promote roughly 2 hours of activity (this is why marathon runners describe “hitting the wall” at approximately that time). This doesn’t mean swim 2 hours then begin feeding (completely depleting is extremely difficult to come back from), it simply means you’ve got about 800-2000 stored calories (for a 150-lb man), so can consume less than your burn rate, depending on the duration of the event. Additionally, the lower the intensity, the more fat will be burned, which will spare stored carbohydrates, so you can get away with even less. Fluid loss must also be considered, with a recommended intake of 16-24 fluid ounces per hour for moderate water temperatures (70-80F). Less is required in cooler water and more is necessary in warmer water. With so many variables, testing and retesting in practice is essential to determine what YOUR body needs.
Frequency. How often you feed will be determined by your preferences and the structure of the swim. If you can feed quickly (10 seconds or less), more frequent feeds (every 15-20 minutes) are preferable for high performance. Many marathon swimmers feed every 30 minutes, which helps keep track of the hours. Rarely would you want to swim more than an hour without a feed, even in the beginning. Hitting that wall is just not worth it.
Delivery. A kayaker or escort boat is great on long swims to pass off feed bottles, perhaps with opened gel packs attached with a rubber band to the outside of the bottle for extra calories if needed. Some swimmers may wish to take in solids on very long swims. All items passed to the swimmer should be tied to a very long rope, so the swimmer can quickly consume the food/drink, drop the container, and continue swimming immediately. Extra care must be taken with gel packs to ensure no trash is left behind. On unsupported training swims, gel packs can be placed in the swimsuit, but this will not help with fluid loss. Place feed bottles on the shore or in a floating feed station at a buoy and loop back often.
Temperature. Finally, the temperature of the fluid can be important. In cold and/or long swims, a warmed drink is often preferred. Be careful not to make the drink hot, as the mouth becomes sensitive after prolonged cold-water exposure. For warmer swims, iced drinks are ideal to help regulate body temperature.
Just like every other skill, feedings must be practiced early and often. Become comfortable with what and how you will eat and drink, and have back-up options in case your stomach becomes upset or you grow tired of an item. Training is a great time to determine what feeding strategy works best for you, and tinker with other minor aspects of feeding, such as electrolytes, caffeine, and flavors.
Marathon Swimmer, www.jenschumacher.org
Sport Psychology Consultant, www.jenschumacher.com