Offsetting Carbohydrates: Bolus Insulin

• I:C Ratio that matches pre-meal BG 3-4 hours after eating • I:C Ratio often varies from meal to meal • May need frequent readjustments, especially for growing children

To properly administer meal-based bolus insulin, insulin to carbohydrate (or I:C) ratios must be established for the patient.  The I:C ratio is the amount of carbohydrate that will be controlled by 1 unit of insulin. For example, if a patient has an I:C ratio of 1:7; one unit of insulin will be sufficient to control the raise in blood sugar caused by 7 grams of carbohydrate. An I:C ratio is considered appropriate if it returns blood sugar levels to the pre-meal value within 3-4 hours after eating. I:C ratios are very individualized and may vary from meal to meal, as well as numerous times throughout the year.

 

Exercise/Physical Activity: Effects on Insulin Sensitivity

Physical activity lowers blood glucose in multiple ways: 

Thus, it is important to accommodate for increased physical activity with either a reduction in insulin or an increase in carbohydrate consumption.

 

 

Offsetting Exercise: Insulin Adjustments

Meal Bolus Adjustment  (for Post-meal activity)

Reducing mealtime insulin doses for post-meal exercise is an effective way to prevent exercise-induced hypoglycemia. The amount of the dosage reduction will need to be tailored to the type, duration, and intensity of activity.

Note that competitive/anaerobic activities may not require an insulin reduction, as they often lead to secretion of adrenal hormones which raise glucose levels.

Offsetting Exercise:

Carbohydrate Supplementation

For activities that take place between or before meals, supplementary carbohydrate can be used to prevent hypoglycemia.  The amount of carbohydrate will need to be fine-tuned for each individual, based on the nature and duration of the activity, as well as the size of the individual.