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From Gothenburg, Sweden:

I am a 49 year old male with a previous history in elite-canoe racing. I got my diabetes about 12 years ago. But up until this winter I have managed to control my blood sugar levels with diet and hard daily exercise. I have no other physical disadvantages.

My question concerns competing in long distance cycle races. The first race since I got IDDM will be in about 2 months. My worries are how to regulate my insulin dose during this two day race over 220 miles. My insulin doses are 18u insulatard morning and 18u in the evening. Then I take three doses during the day with meals, Humalog 12u/meal. When I train on my bike 4-5 times a week I lower the Humalog dose by 4u before training and I lower the evening insulin by 2-4u depending how hard the workout was (generally I do about 24-50 miles on the bike/wotkout). These workouts don't cause me any problems as I drink about 1.5 liters of an isotonic sports drink during the workout. But the problem is how to regulate the insulin during this long race of about 9 hours of cycling at a relatively hard pace and what insulin to regulate. I love my cycling so I do want to continueulin to regulate. I love my cycling so I do want to continue racing.

I hope this makes sense to you and that you will be able to give me some advice. My doctor is a very competent and nice person but when it comes to sports and training he is not so interested. Maybe he thinks I am too old for this. I don't!


First of all, I think it is wonderful that you are competing in long distance cycle races at the age of 49. You are an inspiration to all. Knowing you have diabetes and that you are training for a 9 hour, 220 mile race, in itself is motivating to others to increase their physical activity level.

You have not supplied any blood glucose readings (pre-exercise, exercise or post-exercise). I trust that you monitor your blood glucose before, during and after your training regimen, and that you are in good control of your diabetes.

Most athletes tend to find that if they gradually begin a training regimen and extend there regimen over a pebolically. As a result of their training regimen, gradual adjustments in insulin (usually a decrease in dosage) and food intake can be adapted. By training gradually and making appropriate decreases in insulin, an athlete will be less likely to have to treat insulin reactions by overeating. As you become better trained, you will probably find that you will need to further decrease your insulin dose. It seems as if you have already reduced your daily insulin dosage according to the following factors: Intensity, duration and timing of you training regimen, state of metabolic control, amount of circulating insulin, nutritional status and amount of prevoius training. When training more than 60 minutes at a time you may need to decrease you daily insulin dosage. I usually recommend that a good place to start is to reduce by 10% the dose of insulin that will be acting during the time you are training.

For activities of very long duration, especially activity that is not performed on a regular basis (in your case a long cycle ride), you may need to reduce the dose of insulin by 15 to 30%. On the days when you are engaging in long competition (your 9 hour cycle of 220 miles), you may need to reduce your insulin as you think necessary (this may be 20 to 50% of your usual dosage). However, it is important that you keep in mind that only blood glucose monitoring can help you and your health care professional or Diabetes team determine the changes you need to make in your insulin dosages and the effects these changes will have. I do have one additional comment on food intake. Keep in mind for intense or competitive activities such as marathons and in your case the 9 hour cycle of 220 miles, athletes such as yourself may need 10 to 15 grams of carbohydrate every 30 minutes. Remember an exercising body needs carbohydrate as its main fuel source. Athletes who do not have diabetes have enough stored carbohydrate or glycogen, to exercise intensely for about 90 to 120 minutes of moderate intensity exercise. After that they need to take in dietary carbohydrate to prevent blood glucose from dropping. With individuals who have Type 1 diabetes (IDDM), carbohydate is often needed sooner. How much depends on glycogen stores (the amount of carbohydrate you have stored in your muscles).


[Editor's comment: You might also want to contact the International Diabetic Athletes Association. WWQ]

Original posting 10 Apr 97


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Last Updated: Tuesday April 06, 2010 15:08:54
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