How To: Calculate My Insulin Sensitivity

This section is for everyone.

Insulin sensitivity may not change much at all throughout the day in pre-pubertal children.  After this most people find that they need more or less insulin at different times of the day.

To find out how much insulin you will need to take to cover carbohydrates taken at different meals you will need to find out your carb to insulin ratio.

An average insulin:carb ratio for type ones who are thin is one unit of novorapid or humalog for 12 g of carbohydrate.  As  regular insulin is a third less potent one unit of actrapid for instance covers 8g of carbohydrate.

If you eat the same amount of carbohydrate for breakfast, lunch, dinner and bedtime snack with the same dose of insulin you will find that sometimes it works better than at other times.

Most adolescents and adults need more insulin to cover the same amount of carb at breakfast than at lunch because the dawn phenomenon makes them more insulin resistant for a few hours, often up till 11am in the morning.

Most people have the best insulin sensitivity in the early afternoon eg 2-4pm.

Some people get a “dusk” phenomenon and become a bit more insulin resistant at dinner time.

My son Steven’s insulin to carb ratio is 9 at breakfast, 14 at lunch and 10 at dinner. Because I particularly want to avoid night time hypoglycaemia I give him only 2/3 of the amount of dinner insulin to cover a bedtime snack.  The figures are therefore 9-14-10-14.

You have to  guess and test to work your own figures out.

If you are writing down your blood sugar figures in a book or chart add and take the averages of your bs on  pre-lunch, pre-dinner and pre-bed for at least 3 and preferably 10-14 days.

If you have averages that are above your personal target figure or 5.0 for those who are seeking optimal control you need to have more insulin to cover your breakfast, lunch and dinner respectively.

Accurate basal insulin levels and carb counting skills are essential to do this accurately. If your sugars are running particularly high for any reason eg you have a dental infection or the flu or your exercise pattern has changed over the test period your figures will not be correct for you.

Quick Quiz:
1. Insulin sensitivity….
a Varies according to a person’s individual daily and monthly patterns.
b Worsens with the duration of type one diabetes.
c Is the same for a given amount of carbohydrate for any given person.
d Is irrelevant if a diabetic follows a low carb diet.

Have you got it?
1. A is correct. Once the honeymoon is over there is no particular reason for insulin sensitivity to decrease over time although weight gain and change in exercise and hormone patterns can affect insulin sensitivity in their own right.

Reference Info:
Acknowledgements: Dr. Bernstein’s Diabetes Solution and Dr Gary Scheiner’s Think Like a Pancreas.

Where to Next?
Please now continue to How To: Turn My Pen Into Pump section.