Sports Nutrition Blog

Chicago Marathon Series: Race day fueling and hydration

Fine tune your race fueling and hydration in training

Runners, both new and seasoned, preparing for the Chicago Marathon on October 7th (and other early Fall marathons) likely have a 20 mile training long run on the calendar in the next several weeks.  This is an opportune time to test out your race nutrition plan for the days before the race, the morning of the race, and especially during the race by practicing specific nutrition strategies before, and during the long run.

Start by loading muscle glycogen (carbohydrate) stores. The day or two before the long run rest with a day off or easy workout and increase your usual carbohydrate intake by 100 g from easily digested solid and liquid food sources. In the days before the race you should have a planned carbohydrate loading plan.

Have a good pre-run meal.  Aim for an early wake-up call so that you can practice eating a high carbohydrate pre-exercise meal at least two hours before the start. Many runners like to consume oatmeal on race morning, but it can also be juice, toast, cereal, and skim milk or non dairy milk. Aim for 75 to 100 g of carbohydrate. The more time you allow for digestion, the more you carbohydrates you should consume and the more you can fill your liver glycogen stores. Liver glycogen supplies blood glucose, a source of fuel for your muscles and brain during the long run and the race.

Hydrate and fuel just before the start. Hydrate in the hours before the 20 miler and considering popping a gel, blocks, or liquid shot in the 15 minutes  before the start.

Practice your on-run fueling and hydration plan. Once you settle into the run, start replacing fluid, carbohydrate fuel and electrolytes with a sports drink, preferably the one that is on the course of your marathon. What is your sweat rate in current conditions? How many ounces can you consume per hour? Aim for 40 to 60 g of carbohydrate per hour from your sports drink consumption or anywhere from 24 to 40 ounces per hour from a typical sports drink. Make sure that you have  sense of your sweat rate so that you do not over-hydrate.

This is a great time to practice your race day plan and make any needed adjustments for your big marathon day. Have fun.