How to refuel if you're diabetic.

? I can't seem to find any guidelines about how diabetics should include sports drinks and energy gels and bars into their training. Usually, for a 5K like the one I'm running on Saturday, I know I can make it with just water and then I know how to achieve a balanced blood glucose level when I eat afterwards. However, when I think about the 10-miler coming up on my schedule, I'm not confident at all knowing that I could collapse due to low blood sugar or over-consumption of a drink or gel that would cause my glucose to soar. Any tips would be greatly appreciated.

Cathy Lanuto, Washington, DC

When exercising, hormonal adjustments normally take place which help maintain blood sugar levels while muscles are pulling sugar out of the blood to use for fuel. As you know, with diabetes, this system is not reliable. For this reason, it's critical that you check your blood sugar before and after exercise--and during exercise lasting more than one hour. In this way you will learn your own body's response to exercise.

As a general rule, you should use a carbohydrate supplement when your blood sugar is 100mg/dL or below before exercise. Start with 15 grams of carbohydrate in a sports drink (about 8 oz) or gel (half a packet) every 20 minutes. When training for your 10-miler, stop after 50 minutes and check your blood sugar. If the amount you're taking is inadequate to maintain your blood sugar in the 100 to 150mg/dL range, increase the amount of carbohydrate to 15 grams every 15 minutes.

Every individual is different, so be sure to keep careful logs and look them over to see the effect exercise has on your blood sugar. Once you have this information, you'll be able to safely complete your race and know that you're optimizing your performance by keeping your blood sugar level within an ideal range. Obviously, your medication regimen will also play a large role and will probably need to be adjusted. If you're still having difficulty, a sports nutritionist/registered dietitian can help you create a complete nutrition plan, including pre- and post-workout meals.

Karen Reznik Dolins, EdD, RD, CDN, Rye, NY

For long events I instruct my patients to set up a course for training that reproduces the event. If aid stations are every 2.5 miles then set up a 2.5-mile lap. Cyclists usually have stations every 15 miles. Check blood glucose and weight after every lap or a set number of laps. That means parking your car, setting up your own aid station and having a bathroom scale available. Hydration is an important factor in keeping diabetics out of trouble in long events. The lap system allows you to experiment with how to vary your carb and protein intake during the event.

Mitch Goldflies, MD, Chicago, IL