First, let's clear up a common misperception about swimming. What child has never been told: "You can't swim within an hour after eating or you'll get a cramp and drown"?
Despite the heartfelt conviction of mothers around the world, this statement has very little supporting evidence other than the fact that slightly more blood is diverted to the stomach and intestines during digestion; however, this has little physiological impact on an individual's ability to swim.
That said, swimmers are not immune from the normal gastrointestinal problems that can plague all athletes who train shortly after eating. Still, just as you wouldn't head out for a ride without food and fluids, neither should you hit the pool without—at a minimum—your water bottle.
Of course misinformation, combined with the logistical challenges of refueling in the water, often prevent triathletes from exercising sound nutrition practices at the pool.
For example: Unlike with cycling or running, it is impossible to eat, drink and swim at the same time. There is no convenient way to carry food and/or drinks while you swim.
There is always the chance you will swallow water while swimming, which can upset your stomach and hamper digestion.
The Cold, Hard Facts
While bearing the above challenges in mind, let's begin by examining the practicality and efficacy of race-day swimming nutrition.
First, note that except in an extraordinarily long event, such as Ultraman in Hawaii, which requires each competitor to be accompanied by an escort boat during the swim leg, the opportunities for nutrition and hydration in the water are non-existent at most triathlons. However, due to the cooling effect of the water (as long as the water is not too warm and you are not wearing a wetsuit in water above 72 degrees), most athletes tend to sweat less while swimming than while biking or running.
In addition, unless pre-race preparation has been poor, competitors tend to be well hydrated at the start of an event. Both of these factors tend to mitigate the need for substantial refueling during a triathlon swim.
Nonetheless, heed the following race-day swim-nutrition tips:
- Start off well hydrated with fully-stocked glycogen stores by ingesting easily-absorbed calories before the event.
- As soon as you exit the water, start to re-hydrate by placing a bottle near your bike or in your T1 bag. This is, of course, especially important after an Ironman swim.
- Once on the bike, take in a few calories, depending upon what your stomach is able to tolerate.
- Use the first few miles of the bike to settle into a rhythm, chipping away at the nutritional deficit created by the swim. Do not get overexcited and scrap your nutrition plan. Doing so will hurt you later in the race.
OK, so we know how to approach swim nutrition on race day, but what should you do in training? Should you swear off food and fluids to mimic the mild post-swim nutritional deficit you're likely to experience on race day, or should you refuel to avoid a workout bonk?
Many athletes schedule their swim as their second or even third training session of the day and, as such, are often never too far away from being dehydrated (or bonking) unless they follow sound nutritional strategies as a matter of course. As a result, it's imperative that you heed the delicate nutritional balance required to maintain health and support a rigorous training (and living) schedule.
To this end, take advantage of the deck at your local pool to lay out whatever you think you may need to eat or drink during a workout. Unlike your long rides, where the next store could be an hour up the road, in the pool, you're never more than a few yards from a sugar boost.
A water bottle and a gel should suffice for a 90-minute swim unless you hit the water in an already glycogen-depleted state. If you're planning another training session immediately following your swim, however, then ingesting an energy bar or half a sandwich directly after your cool-down will help to re-stock your energy stores.
It can be useful to view your swim-workout nutrition not as a standalone issue but, rather, as a part of your overall nutritional plan. While you likely will be able to make it through a 3,000-yard workout without eating or drinking, doing so can compromise your workouts later that day. So train smart, plan ahead and eat up.