Ketogenic Diabetic Athlete

#24: April 2016 Update on My T1D Management


Compared to March, my glycemic control was similar with a lower mean blood glucose (BG) but with more hypoglycemia. I lifted weights 6 days/week, cycled 1 day/week with one rest day this month for an average of 17 hrs/week of exercise. I had 14 of 127 (11%) glucose readings < 51 mg/dl, but all were without symptoms due to either nutritional ketosis or hypoglycemia unawareness (see blog post #12 for more details). None were > 200 mg/dl leaving 89 of 127 (70%) between 51 and 120 mg/dl and 24 of 127 (19%) between 121 and 200 mg/dl. Insulin doses were adjusted slightly with an increase in basal and a reduction in mealtime insulin to address some increases in fasting BG and post-meal hypoglycemia, respectively. The summary table of current and previous mean BG and insulin doses is shown below.

Below are my BG reading along with exercise type and time so you can see how the exercise affects my glycemic control.

The table below shows the summary of current and previous BG variability results. Some results were improved (coefficient of variation = 39%, mean time of hyperglycemia = 3.0 hr/day), some not (mean time of hypoglycemia = 1.5 hr/day), compared with the previous month.

The actual daily insulin doses and daily totals are shown in the graphs below.

My breath ketones since June 2015 are shown below. I remain in continuous nutritional ketosis. I occasionally check urine ketones which remain positive having been in nutritional ketosis over over 4 years now. Some individuals can have negative urine ketones despite being in nutritional ketosis due to the renal reabsorption of acetoacetate which is what the urine test strip is detecting.

The graphs below show the new metric I conceived of last month with one change. On the x-axis is the Breakfast and Dinner mealtime insulin dose (Humalog) plotted against the change in BG, this time Post meal BG minus Pre meal BG on the y-axis. Thus positive values represent an increase in BG and negative values represent an decrease in BG after the meal. Also, note that I removed 2 of 30 Breakfast points and 12 of 30 Dinner points from the graphs where the Post meal BG was not in the range of 51-120 mg/dl. The rationale for this is to eliminate mealtime doses that were “incorrect” so to speak. This way the graph shows both that larger doses of insulin reduce BG more (obvious), but more importantly even when the resulting Post BG was in an acceptable range, that there is a wide variation in the amount of BG reduction for any given dose of insulin. This is the frustrating part of T1D that we just have to live with.

The graph below is new this month and positive values represent the increase in BG due to weightlifting. There were only two negative values representing a reduction in BG due to weightlifting. The main feature is the wide variation in the glycemic response to the same type and similar duration of intense exercise. On two days of the month a 15 mile bike ride resulted in a decrement in BG of 42 and 32 mg/dl (not shown in the graph).

The mean increase in BG due to weightlifting was 56 mg/dl. This was completely due to the hormones my body creates in response to the exercise, i.e. no food or glucose was consumed. The red linear regression line declining hopefully means that these increases in BG due to weightlifting will continue to decline as I adapt to the exercise.

Till next time ….