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How I fueled to swim across the Chesapeake Bay

On June 8th, 2014 I entered the waters at Sandy Point State Park with over 600 other swimmers to make the 4.4 mile swim across the Chesapeake Bay to Hemingway’s Marina on the other side. Since I often get asked about my own fueling approach I decided to take this opportunity to share what I planned to do, what I did, and the results – both good AND bad.

Fueling for endurance events is always a challenge, but long swims present their own set of obstacles:

1) You have a limited capacity to carry any food or beverage (unless it is a race requiring an escort for each swimmer, in which case your support vessel can carry it);

2) If there will be boats with food or beverages on the course it can be difficult to sight for them (and you won’t find them as frequently positioned as say, on a running course);

3) Stopping to eat or drink means stopping forward progress; and

4) The constant horizontal position coupled with waves or choppy seas can make for an unsettled stomach.

The average time for the Chesapeake Bay Swim is roughly 2 hours 30 minutes; this year’s winner finished in 1 hour 29 minutes, while the last finisher was out in 3 hours 47 minutes. So you can see there is a wide range of completion time, similar to the spread one might see in a half-marathon.  Having done half-marathons, marathons, and Ironman races I can attest that an open water swim of this length can be just as brutal as other sport races double or triple its time length.  The water conditions and loosely marked race courses are a big part of it.  Plus, walking isn’t an option.

I knew my fueling during the race would be limited (I’ll get to that plan shortly), so I decided to focus on my pre-race fueling. My overall goal was to ensure I started the race with maximum glycogen stores and adequately hydrated.

24-48 Hours Out

The original concept of carb-loading involved several days of decreased carbohydrate intake during intense training (to deplete deplete glycogen stores and “prime” the muscles for uptake) followed by several days of decreased training volumes and increased carbohydrate intake. The idea was that glycogen-deprived muscles would maximize glycogen stored once carbohydrates were reintroduced and activity was decreased. These days we know that simply increased carbohydrate intake in the 1-3 days leading up to an event (typically coupled with a decreased in training volume as well) can maximize glycogen stores.

My training volume decreased about 72 hours out from the swim, and I began increasing my carbohydrate intake about 48 hours pre-swim. One should anticipate weight gain during this period – for every gram of glycogen your body stores it also retains 3 grams of water.  The average glycogen storage capability of an individual is 300-400 grams, so that means you can gain up to 3-4 pounds just by maxing out glycogen stores.

But while it’s good to increase carbohydrate intake, it’s still important to monitor overall caloric intake.  I kept my protein intake the same at meals to ensure I was meeting my protein needs, but I was careful to keep my fat intake in check in order to keep my overall calorie consumption in line with my current activity needs (such as reducing portions of nuts, olive oil, and desserts).

Additionally, since I tend to get more than the minimum recommended intake of vegetables per day, I reduced my portion size of them at meals and snacks. This served two purposes: it decreased gastrointestinal contents slightly while still keeping me regular, and the fiber intake from vegetables which previously kept me full was now reduced and making room for my carb increase.

More of a concern to me than the carbs was my hydration. I have a very high sweat rate and tend to lose quite a bit of sodium in my sweat. In a 90-120 minute swim I could expect to lose at least 4-6 lbs (or roughly 64-96 oz of fluid). The negative effects of dehydration are typically seen at 2% loss of body weight, which for me is 3-4 lbs. Additionally, the high electrolyte loss can contribute to decreased performance and raise the risk of cramping, hyponatremia, and gastrointestinal problems.

I started increasing my salt (and fluid) intake 24 hours before the race. Some may choose to drink a sports drink throughout the day; I prefer to choose saltier foods or add more table salt to my meals (cottage cheese, soups, lunch meat, rice with soy sauce are a few examples). I also decided to consume a high sodium sports beverage the night before the race as well. There are a few products available but I used The Right Stuff, which has over 1700 mg sodium in it (Osmo and Skratch are other brands of which I am aware). I consumed this with about 32 oz of fluid (sipped, not chugged).  The increased sodium intake allowed me to retain more fluids going into the race – another factor which can contribute to weight gain pre- event.

0-4 Hours Out

To line up with the tides and current my wave of the 4.4 mile swim was scheduled to kick-off at 10:45 am. About 4 hours out I had a bowl of cereal, and I packed another snack bag of cereal along with 32 oz of sports drink mixed with another packet of The Right Stuff to take to the race. My goal was to sip on this fluid up until 15 minutes or so before the start. I ended up eating the bag of cereal and finishing most of the fluids, and I felt ready to go. I had urinated twice throughout the morning before the start so I felt confident I was well-hydrated.

During the Race

Based on my pre-race plan I had decided to do the swim without stopping at the fueling boats unless absolutely necessary. I stuffed a gel packet into my cap and my wetsuit just in case, but truthfully I was more worried about fluids and electrolytes than carbs.  I anticipated a swim in the 1:40 to 1:50 range, which is just over the time where carb replenishment can really become a factor.

Despite the placement of a support boat at mile 2 and 3, I never recall seeing them. Conditions were good overall, but there was a chop that made sighting very difficult. That chop coupled with a few gulps of Bay water also led to a slightly queasy stomach about 1 mile from the finish. I felt so beat up from the waves but I didn’t really notice any energy depletion, so I never reached for the gels (especially since I already had an upset stomach and wouldn’t have access to fluids with which to consume them).  I ended up exiting the water in 1:48:01 and just a little bit wobbly.


My stomach showed no interest in eating or drinking anything immediately following the race, which isn’t uncommon but put me on alert. I grabbed a bottle of water and Gatorade along with some orange slices from the race finish, but nothing really tasted or felt all that good in my gut.  In fact, I was just overall uncomfortable.  The smell of the Bay lingering on me added to the nauseating feeling during the ride home as well. I had packed a recovery snack of Greek yogurt, oats, salt, sugar, and blueberries, but it did not appeal at all.

But once home I forced down a handful of salty crackers along with more fluids and found my stomach starting to settle and allow things to move along. I finally urinated about 3 hours after I had finished the swim and it was closing in on the “apple juice color” – a sign I was still low on fluids. I eventually was able to eat (eggs, cheese, brown rice, veggies, and plenty of salt) but the unsettled stomach continued through the evening (the next morning I was ravenous).  Continuous water intake coupled with the salty foods helped get my hydration back up to normal. Important to note: water alone is not the solution in these scenarios. The electrolytes are critical for returning blood plasma volume to normal range and aiding digestion.

Lessons Learned

Overall I was happy with the race, especially given the choppy conditions.  I find it’s always good to take a look at what did and didn’t work in order to make changes for future race strategies.

1)      My carb-loading approach seemed to work. I had pretty good energy throughout the entire race, and most issues came from the lack of not swimming in rough water on a regular basis.

2)      While my energy stores seemed to have held up, the lack of fluid intake during likely contributed to a poor hydration and electrolyte status by the finish. Unfortunately, my fluid needs are so high that anything over an hour (or over 30 minutes in hot temps) requires fluid/electrolyte replacement during it. I had considered using a foldable water bottle (shoved into my wetsuit), but it just wasn’t worth the incredible chaffing I would have experienced. If I ever I take on a race longer than this length I would absolutely make sure I had access to fueling options during the swim.

3)      Next time I would ensure consuming more sports drink directly following the finish to enhance recovery, or at least have on hand more salty snacks to consume with water.

Events like these show that fueling is important, and everyone’s approach and needs will be different.  Keep track of your fueling tactics during training and racing – this can help hone in on what works and doesn’t work for you.

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