How to I adjust my running BG by changing my running speed?

I went running this afternoon while I still had some IOB from a correction (not much, I corrected only 0.7U). I was dropping way too much, so I tried to do sprints to get my BG up, but 5 minutes of sprints did not make a difference. In the end, I had to come home after 45 minutes because I was dropping below 50 (even after eating sugar).

I did not lower my basal before running, because it was a last minute decision, so I thought it would not make a difference if I shut off my basal right as I went running.


Did you bring your PDM with you on your run? It’s always a good idea to bring it with you. A lot of times I only turn off basal right when I start, and it helps a lot. Always bring your PDM.

The trick to bringing your BG up with running is by going over your lactate threshold heart rate. Generally this will be about a 5k race pace. You have to do it long enough. So on the 5 minutes of sprints, were you doing sprints and resting? Your HR comes down during the rest. The idea that the recent study showed of 10 seconds of sprinting followed by some rest, and having it bring blood sugar up is not really gonna work for an athlete. For someone who is in shape like you, it takes a serious effort to have the training stress cause enough cortisol to raise your BG. So rather than 5 minutes of sprints, you would probably need to do at least mile of LTHR running.

That can indeed bring your BG up. The problem is, you are then cooked for the rest of your run. If you want to have a long run, you are better off eating sugar and then enjoying your long run rather then exhausting yourself with a hard effort just to bring your BG up.


Yeah listen to Eric. I got mine from about 70 to 110 running 2mi this morning. For me I don’t have to run 5k pace to cause a spike. Half-marathon pace will do but everyone is different. The fastest way to get my heart race up is 400’s on the track with 30s rest (~90sec very hard/30sec easy).


Yes. Over 10 minutes I ran hard 5 minutes and jogged 5 minutes, in 4 or 5 times.

I get it, thanks a lot, @Eric!

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Thanks very much @CarolynA. I like the rule you give on 90 sec very hard/ 30 sec easy, because I don’t really know what a 5K pace would be for me, I am not an experienced runner.

If you were to try to run for 25 minutes as hard as you can, but at an even pace, that would give you a general idea of your LTH.

If you are only able to go for 15 minutes and then can’t keep going, it was too fast a pace.

If after 25 minutes, you think you still have some left, then it was not fast enough.

Try to imagine the pace that you could only do for 25 minutes. That’s a good ballpark idea. But to accurately know, you would need either a lot of heart rate data, or a blood test for lactate.

But a general ballpark of that pace can tell you where you will spike. And like Carolyn said, you can do it with sprints if they are significant enough to stress you. The key is your heart rate. You can get a spike with a slower pace and longer, or a faster pace and a bit shorter. There are a lot of different ways to do it. The shortest interval I do is generally 1 minute, and that is rare. Usually I do longer intervals. But there are all kinds of ways to spike. The key is heart rate.

But, in general, I think 10 or 20 second sprints are too short for someone in good shape. Unless you do a lot of them and keep the recovery period short so that your heart rate stays elevated long enough!

Even if you are not an experienced runner, I know you are in good shape physically from all your exercise. The heart rate that causes you to spike will be different than someone else.

It takes a lot of time and practice to know it exactly! It really is different for everyone depending on the shape they are in. A workout that makes me spike would probably just be a warmup for Carolyn. :smiley: