Please note that the following is based on just my experience and not a medical advice. However, sometimes it is good to read about how others are dealing with their conditions to get ideas for yourself (check with your doctor before deciding anything).
What makes my running a little bit more challenging, is that I have had Type 1 Diabetes since I was 16 years old. This means I need to plan all my runs beforehand, having enough fast carbs and blood sugar sensor with me. I love it that nowadays longer runs are so much easier without having to carry blood sugar measuring equipment with me, but just being able to see the value from my Garmin Forerunner or my cellphone with a sensor. Thank you Libre and Abbott for all the work you constantly do in order to make it easier for us.
Being a DMT1, means marathons require some more planning too and it is a constant learning journey. At the beginning of my marathon journey, it was a lot simpler with balancing the carbs and insulin since I didn’t race nor run very fast. I just had the blood sugar measurement equipment and the insulin with me, and some extra gels. I drank sports drinks at every drink station and started the race with a higher blood sugar to ensure it didn’t drop too low. I also decreased my base insulin level with a small dose in the morning and the evening of the race (at this time I was on two times a day base dose)
A few years ago I changed my base insulin to Tresiba once a day which works better for me and since it has a more long-term impact, I started to decrease the dosage three nights before the race with one unit.
It got a little bit more challenging when I started running faster with higher heartbeats and was setting myself tougher targets. These both made my blood sugar skyrocket from the start (the stress hormones like adrenaline can raise the levels when you are competing). And this in turn meant that I started feeling a bit sick at around 15k and I had to stop for extra 1.5 units of fast-acting insulin. Since it took a while to get the impact, I couldn’t take any carbs before way over hallmark. Thus I didn’t have any strength left after 30k and ended up with sub-optimal results.
In London 2023 I again lowered my Tresiba dose with one unit 3 days before the marathon day. This meant 14 daily units. I also set my low blood sugar alarm to 4.5 and high alarm to 14 to ensure I react early enough and specifically avoid lows, since I wanted to keep my sugar storage in a good enough shape. During the competition day, I started getting nervous before the start and that meant my blood sugar started to increase without any active insulin in my body (I have the habit of eating my breakfast 3 hours before the start). It doesn’t matter if it increases a little, but with myself what happens is that it jumps, sometimes even to 20 within the first 15 kilometers and stays there for another 5, before around the mid-marathon it starts decreasing gradually. This means I cannot take any carbs before the half way, and only a little after that. In London I ended up with 16 as the highest. Far too high anyhow to get me to finish strongly. I got fed up with this tactic, since too often I ended up feeling nauseated due to high sugar and on the other hand not enough energised due to not being able to take in anything other than water.
So only 3 weeks after London marathon, I tested again with a marathon in Helsinki to find a new tactic. This time I dosed 1.5 units of fast-acting Liprolog 30 minutes before the start in the hope that it would stop the increase and enable me to take some energy also within the first half of the marathon. This seemed to work well and thus I decided to continue with this tactic. I attended the second biggest Helsinki marathon in August 2023 and finally made it under 4 hours with 3:54. Blood sugar was still a bit too much on the high side and I could only take some carbs during the run, but a huge improvement and the best of all: I felt like my diabetes didn’t stop me from running according to my condition.
North Strides 