Fueling Your Body During Training*

I don’t know if I can do this…

Eight weeks to go. Many of you will say “I’m Type A, “ and clearly, the phrase “I don’t know if I can do this” may not be in your vocabulary when it comes to training for your race. However there may be moments when circumstances of the day (stress, weather, work, family) may interrupt your pre-planned training schedule. Well, Type A or not, life is going to happen, and you will find a way to do this.

There is an art for training for a race. All the literature, all the training books, all the internet resources will provide some guidance and you could say there is a science to training the right way for you to finish this race. But there is an art to making it work for your circumstances.

You can’t run on fumes.

Your car doesn’t run on an empty tank of gas, so why do you think your body is any different. The body stores glycogen in muscles and in the liver, and it is used with oxygen to create energy. But that system doesn’t fully kick in when your foot hits the ground as you take off for training. More immediately, your body uses glucose stored in your blood (anaerobic-glycolytic system). As your breathing rate increases and you continue running for more than 5 minutes, the energy production systems switch to an increased demand on the aerobic system (oxygen and glycogen). As you continue to push the distance and intensity of your run, the by-products of this system start to back up in your blood stream (Blood/Lactate Threshold), and you can’t get enough oxygen to continue to make energy. A condition more affectionately called “hitting the wall.”
So here are a couple of important points:

(1) Gradual increases in training make your lungs more efficient at bringing the oxygen into the aerobic system so you can use stored glycogen. This will fuel you for longer periods of time.

(2) Taking in some type of simple carbs or carb/amino/electrolytes during your run, replenishes your blood glucose levels. This can bolster the balance between anaerobic-glycolitic and aerobic energy production systems.

(3) There are many ways to “hit the wall,” and some are a lot less graceful than others. Sian Welch and Wendy Ingraham are two athletes that immediately come to mind. In 1997 with less than 100 feet to go in the Kona Ironman, both contestants went down and made a painful looking crawl to battle for 4th and 5th places. Their bodies were completely depleted of any fuel. As a more relate-able example, in my first ever 20 mile training run, I was equipped with 32 ounces of Gatorade and a couple of granola bars. That resulted in a hamstring strain at mile 16, and my marathon training went to an immediate taper and recover mode. Save yourself the drama and learn how to fuel your body appropriately.

There are several variables that affect how many calories you burn per mile when running. Factors include one’s weight (including muscle vs. fat ratios), running environment (incline, wind, etc.) and intensity of running pace. The internet is chock full of calorie counters to help you set a customize-able program, but here are some basics. These general recommendations are based on a run of 45 minutes or longer:

(1) Eat 400 – 800 Calories about two to four hours before you exercise. This “snack” should be a balance high in carbohydrates, low in fat, and moderate amount of protein.

(2) Consume 120 – 240 Calories per hour of running/activity. This will replenish your essential blood glucose levels. Stick to foods that are high in simple carbohydrates and easily digest-able. Drink at least 8 oz of water with any food consumed during exercise. This is one of the more tricky aspects of fueling your body during longer runs. Since the blood is diverted toward your muscles, your digestive system is strained. Don’t make refueling more difficult than it already is. Energy gels are popular, but so are pretzels, bananas and even baked potatoes. See what works for you as you train during the next two months.

(3) Fluid intake should match fluid loss. Weigh yourself before a run, and then weigh yourself after your run. For every pound of weight lost, you should take in an extra 12 – 24 oz gradually during the day. During your runs, you should consume between 5-12oz every 15 minutes of exercise. (Don’t forget to factor in extra fluids when you take in your carbs.) Fluids may also contain electrolytes and carbs to help replenish your body. It is recommended to have 100 – 110 mg of sodium and 38mg of potassium. There are various sports drinks and juices that fit the bill, but it has to work for you. Consider what the race will have available on the course, and see if those are options that work for you. During training, you may choose to have supplies placed accordingly on your runs.

(4) After your run, it is recommended to have 100 – 400 Calories immediately (and no more than 30 minutes) to stimulate glycogen recovery. This snack should be primarily carbohydrate with some protein.

(5) Last, but not least, you should have a full meal within two hours of completing your run. The ratio of 3:1 carbs to protein will begin the process of replenishing glycogen and rebuild muscle tissue… And don’t forget about taking in enough fluids (see #3 above).

So there is your science lesson for today. Use the next month or so to figure out what foods and drinks work best for your body. All digestive systems are not created equal, so your training runs are the perfect time to sort out what works best for you. Don’t forget to check The New Jersey Marathon Home Page to view the page about your specific race to see what products will be available on the course and where, if any.  If you try those during your training and they don’t agree with your body, you may need to get creative and carry things with you. That can add another dimension to your training.

The take home lesson: training for a marathon or half marathon can be challenging enough with everything else that life throws at you. Fueling correctly before, during, and after your runs, is a variable within your control… and doing it properly can make the experience a great success. Who knows, it may even change how you look at nutrition overall.

Christine M. Scarano PT, DPT, CKTP
Doctor of Physical Therapy
Certified Kinesio Taping Practitioner


* Much of the information referenced in this blog post can be found in: March 2010 Issue: Marathon Fueling — Runners Need Proper Nutrition and Hydration for the 26.2-Mile Stretch
By Janice H. Dada, MPH, RD, CSSD, CDE, CHES 
Today’s Dietitian
Vol. 12 No. 3 P. 36

One thought on “Fueling Your Body During Training*

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