Compared to April 2016, my glycemic control was similar with a higher mean blood glucose (BG) but with less hypoglycemia. It is a consistent theme amongst those with type 1 diabetes that mean BG and incidence of hypoglycemia are inversely related i.e. the lower the mean BG, the more hypoglycemic episodes and vice versa. It is somewhat annoying that achieving closer to normal BG is met with more hypoglycemia.
On May 12th I strained my back doing a deadlift which required a 10 day period of recovery. This in turn resulted in an increase in BG and the need to increase insulin doses due to being less insulin sensitive. I have noticed this association between exercise and insulin sensitivity since 2007 and is one reason that exercise is beneficial especially for those with type 2 diabetes whose initial and persistent abnormality is insulin resistance.
The summary table of current and previous mean BG and insulin doses is shown below. Compared to April 2016, my exercise time decreased to an average of 12 hrs/week due to the back strain. The mean BG increased from 90 to 95 mg/dl as did my mean total daily insulin dose from 34.1 IU/day to 35.3 IU/day primarily due to an increase in rapid-acting insulin (Humalog) which I use to correct hyperglycemia. I had 11 of 127 (9%) BG readings < 51 mg/dl, but all were without symptoms due to either nutritional ketosis or hypoglycemia unawareness (see blog post #12 for more details). I had 86 of 127 (68%) BG readings between 51 and 120 mg/dl, 27 of 127 (21%) between 121 and 200 mg/dl, and 3 of 127 (2%) > 200 mg/dl.
Below are my BG readings along with exercise type and time so you can see how the type, time, cessation, and resumption of exercise affects my glycemic control.
The table below shows the summary of current and previous BG variability results. Some results were improved (mean BG Δ per hour = 9, mean daily BG range = 72, mean time of hypoglycemia = 1.3 hr/day) while some were not (standard deviation = 39, coefficient of variation = 42%, mean time of hyperglycemia = 4.4 hr/day) compared with the previous month. The measures of BG variability were defined and explained in blog post #10.
The actual daily insulin doses and daily insulin dose totals are shown in the graphs below. You can see the need to increase insulin doses on the first non-exercise day and the reduction in insulin doses as soon as exercise resumed. This means that in my case improved insulin sensitivity due to exercise lasts no more than 24 hours.
My breath ketones (acetone) since June 2015 are shown below. I remain in continuous nutritional ketosis due to daily consumption a ketogenic low carbohydrate whole food diet. I occasionally check urine ketones which remain positive having been in nutritional ketosis for 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. These persons would need to use either breath acetone or blood beta-hydroxybutyrate testing to confirm nutritional ketosis.
The graphs below show the change in BG that results from mealtime rapid-acting insulin. On the x-axis is the Breakfast and Dinner mealtime insulin dose (Humalog) plotted against the change in BG, i.e. Post meal BG minus Pre meal BG on the y-axis. Thus positive values represent an increase in BG and negative values represent a decrease in BG after the meal. Also, note that I removed 5 of 31 Breakfast points and 14 of 31 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 graphing 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 was new last month and shows the change in BG due to weightlifting. On the y-axis, positive values represent the increase in BG due to weightlifting. There were five negative values representing a reduction in BG due to weightlifting. The main feature is a gradual reduction in the extent of BG elevation due to intense exercise through the month of May. Perhaps I am adapting to the activity such that my body does not perceive it as stressful.
Beginning in June, I have adjusted my weightlifting schedule to 5 days/week with less intensity (less weight) and more volume (more sets/reps) while also reducing the intensity of swimming and cycling on the “rest” days. The purpose is to reduce my exercise intensity to hopefully reduce the BG elevations further. The rationale for doing aerobic exercise on “rest” days is to maintain insulin sensitivity which in turn decreases variability in BG and the need to adjust insulin doses.
Till next time ….