A New Method To Predict Carbohydrate Needs for Diabetics during Exercise
Abstract Number: 2236-PO
Authors: GERHARD E. HILDEBRAND, EDWARD H. MATHEWS
Institutions: Pretoria, Gauteng, South Africa
Results: If a Type 1 diabetic athlete ingests too much CHO during an endurance event it can lead to hyperglyceamia. On the other hand, if the athlete ingests too little, hypoglyceamia can result very quickly as blood glucose release from liver stores can be up to four times smaller than in a healthy person.
Currently, empirical suggestions for CHO ingestion are published in diabetic books. However, these suggestions do not account for the type of CHO and personal characteristics such as fitness, efficiency in absorbing CHO into the blood, efficiency of glucose delivery by the liver, etc. This can lead to incorrect CHO dosage.
We have developed an easy-to-use theoretical procedure where the correct links between CHO type and all the important elements for a specific individual are considered. The procedure was theoretically derived using energy balance techniques.
The complicating factor of different levels of glucose delivery by the liver in different Type 1 diabetics can be omitted if we never utilise the liver store. If the diabetic ingests the correct amount (grams) and the right type (GI) of CHO, the liver stores will not be used and there will also be a negligible rise in blood glucose.
Predictions by the new procedure (Table 1) was verified against measurements by respectively Bosch et al and Welsh. We have to keep in mind that the procedure only holds true if the diabetic uses the correct amount of insulin. Too little insulin during strenuous exercise can result in high blood glucose as the glucose cannot be utilised if the insulin levels are too low. More about finding the correct insulin levels for exercise will be given in another paper.
Table 1: Examples of CHO needs (in equivalent teaspoon sugar ( ets )) for exercise by an average 70 kg person.
|Time||30 min||45 min||60 min|
|Cycling at 21 km/h||3||4.5||6|
|Jogging at 11 km/h||8||12||16|
|Walking at 6.5 km/h||2.5||5.5||7.5|