during a Half marathon

Type 1 Diabetes & Managing Blood Glucose Levels During a Half Marathon

Paul Coker here from 1BloodyDrop.com. For those of you that don’t know me. I’ve just marked my 40th year of living with Type 1 Diabetes by running 40 half marathons. Throughout my journey on those half marathons, people have asked me on almost every single run, if not every run, how do you manage your diabetes on a half marathon?

On my previous video, I was talking about how I manage my blood glucose levels in the lead up to a half marathon. I’m now going to be talking about how I actually manage them during a half marathon.

Now, we could be talking about during the half marathon, but if you’ve not run before this could equally apply to going out for a 10K run. It could equally apply to going out for a one hour run or a one and a half hour run, a two hour run. It’s not about the distance. It’s actually about the time. I spoke extensively about the preparations to my Diabetes management I make before a run. Now, I’m going to be talking about the preparations, the measures I take during a run.

Those measures are predominately about lowering the amount of insulin I have circulating in my body during the run. I’ll touch real briefly about reducing the amount of insulin you have on the last meal before you run and about lowering your background insulin if you’re using an insulin pump during the run. Now, I do use an insulin pump and whilst I am running, I take a reduction in my basal insulin, my background insulin, of 80 to 90%. The guidelines teach us that we should start at 50% reduction and that’s where I’ll suggest you start if you’re new to this, but don’t rely on the guidelines. The guidelines are your starting point. If you find that 50% of insulin reduction is still too much insulin and you’ll know because you’ll keep going hypo, then don’t be afraid to lower it even more.

I did run some of the runs without any insulin but I did tend to find my blood glucose levels were climbing far too much after a run if I did that, which is why I retain a 20% of my normal insulin going in whilst I run. The other thing I do is to monitor my blood glucose levels at least once every 30 minutes whilst I’m running. Now, if you’re new to running, I’d suggest that you do every 15 minutes and if you’re an experienced runner, every 30 minutes is probably about right in my experience.

And in doing that, you can begin to build up the trend of what’s happening. Now, if you’re using a continuous glucose monitor, glance at the glucose monitor at least once every 30 minutes and again, look at the trend. The trend is the important thing here. We want to prevent hypos and the other thing is at least once every 45 minutes take some glucose on board. That could be in the form that you prefer. For me, I prefer to eat some fruit if I can. If I need faster acting glucose than fruit, then I’ll look at things like jelly babies and if I have started an experience, a hypoglycemic episode, I will take some jelly babies or some dextrose on board or some people like to take gels at this point. Personally, I don’t enjoy gels. I don’t like them and I find I feel quite sick after taking them. So they’re not for me but if they work for you, hey, that’s great. Carry on.

Now, during my run, I’ll carry on doing all those things until 30 minutes before I finish. When I get to the 30 minutes before I predict I’m going to finish, I actually have my background insulin, my basal level, come back to 100% of normal. I know that it’s not going to actually have a significant impact until at least 30 minutes, perhaps an hour, but that means that then my background insulin is ready for when I finish. The moment I cross the finish line I get a very, very small dose of insulin. This has been born from experience. Most people when they finish a run that’s more than an hour, they find that a huge amount of adrenaline is flowing around in their system and it takes a while for that adrenaline to stop being active. What that means is adrenaline is there to make you insulin resistant. That’s great while you’re running and it serves us really well even if we don’t have diabetes. But if you do have diabetes then you’re not going to suddenly be able to run, pop a load of insulin production to deal with it and your blood glucose levels will spike like crazy.

When they do spike like crazy, be very, very conservative about treating them. If you gave the normal amount of insulin you’d give for the kind of blood glucose levels that I’m talking about, when I was first doing this I would see blood glucose levels of 15 or 20 even at the end of a run. If I was to give a normal prescribed correction for that, I would then find I was hypoglycemic really, really quickly and that would be a hypo that would carry on repeating itself for hours and hours. So I learned over the course of doing 40 half marathons a very small dose of insulin. In my case that’s one half of a unit. That’s half a unit to prevent my blood glucose levels going really, really high.
Now, it doesn’t stop them completely. They still carry on climbing. But what it was able to do is instead of climbing and climbing and climbing I was able to climb and climb and just stop it climbing too much and then they’d come down again very, very gently, which is exactly what I want because I don’t want to be hypoglycemic after a run, which I’ll be talking about in my next video, how I deal with my diabetes after a run. I’ll see you in the next video.