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From Phoenix, Arizona, USA:

I am 20 years old, have had type 1 diabetes for four and a half years, and I am currently training to run the Kona Marathon with Team Diabetes. How often is it necessary to eat/drink on long runs to keep my blood sugar up? Also, can you recommend any specific sports bars, gels, or drinks that would be the most effective? Can you recommend any specific sports bars, gels, or drinks that would be the most effective?


Congratulations to you on your choice to train for the ADA's Kona marathon!

Both carbohydrate availability and hydration levels become limiting factors in endurance and performance, and therefore must be foremost on the minds of endurance athletes both with and without diabetes. If you are using an insulin pump, you have the ability to more closely mimic the non-diabetic response to endurance exercise via a reduction in basal rate. In this case, your intake of carbohydrate should be what is recommended for all athletes. Recognize that a larger amount of carbohydrate may be necessary to maintain blood sugar if you are unable to reduce circulating insulin levels. You'll need to individualize this with frequent blood glucose monitoring, and realize that changes in your training regimen may change your blood sugar response to exercise. In general, the American College of Sports Medicine recommends carbohydrate ingestion during endurance races as noted below:

During intense exercise lasting longer than 1 hour, it is recommended that carbohydrates be ingested at a rate of 30-60 grams per hour to maintain oxidation of carbohydrates and delay fatigue. This rate of carbohydrate intake can be achieved without compromising fluid delivery by drinking 600-1200 ml per hour of solutions containing 4%-8% carbohydrates (grams per 100 ml). The carbohydrates can be sugars (glucose or sucrose) or starch (e.g., maltodextrin). ~ACSM

A further recommendation of 8-12 ounces (240-350 ml) every 15-20 minutes of a sports drink containing carbohydrate is a good one as the smaller volumes may minimize stomach discomfort. This also helps to prevent a fall in blood glucose concentration and to blunt the hormonal response to prolonged exercise, slowing fatigue. Again, depending on your insulin regimen, your requirements may vary.

Many athletes use a combination of solid food bars, sport drinks, and gels, all of which are certainly adaptable to the diabetic athlete's routine. There are a variety of brands on the market and your choice will depend on a number of factors, including taste and tolerability. Use your training sessions to experiment with a regimen. Pattern your blood sugar response to the exercise by monitoring and ingesting at least every half hour. This should assist you in making both insulin and carb intake adjustments.

Lastly you may wish to further research carbohydrate and hydration during endurance exercise by visiting a couple of on-line resources:

Here's wishing you success in both marathon training and participation!


Original posting 19 Jun 2001
Posted to Exercise and Sports


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Last Updated: Tuesday April 06, 2010 15:09:22
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