FUDiabetes

Post-exercise muscle glycogen replenishment

I wanted to post this image because it’s a great visual representation of muscle glycogen getting replenished during the night, shortly after exercise.

You can see 3 distinct drops on this trace. Each rise in the trace is from drinking juice to get back up.

This is why I frequently mention the importance of post-exercise carb replenishment. When you use it, your body will replace it. So getting sufficient carbs after you finish your exercise is extremely important. The drops demonstrate how the body is pulling glucose out of the blood to replace the used muscle glycogen.

Picture the seagulls from Nemo, squawking “Mine! Mine! Mine!” as the muscles desperately grab what they can to replenish.

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This is a really awesome visual demo!

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This is a good follow-up image. You can still see the 3 drops from the nighttime, but now the body has finished it’s frantic glucose grabbing, and everything is back to flat.

image

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Do you find the timing is pretty consistent? You see a few waves that are about 2.5 hours apart… do you think this corresponds to some kind of step function in how the body is replacing glycogen? Or something else?

That is hard to say. A lot of it could be from CGM lag. The pattern was drinking juice, bringing my BG up, and then the body sucking it out of my blood.

Most of the time I exercise in the evening, so this is happening in my sleep, and I am not doing BG checks to see it.

I am sure there is some fluctuation in how the body does the replenishment.

From what I have read, the ideal way is to take in an immediate carb source right after, followed by feeding it incrementally for several hours in intervals after the exercise.

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Do you not just use a temp reduced basal overnight? If I exercise, I often use a -10% or -20% basal overnight (or for the next 8-12 hours) so that I don’t go low. Are there downsides to doing this rather than eating carbs?

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Definitely! Temp basals are great for that. I frequently do temp basals at night after exercise. For me it can run anywhere from -10% to -60%.

I didn’t this time because I had just put on a new pod right before bed, and with new pods it usually takes a few hours for my tissue to get ramped up and absorb it well (I usually “prime” the site by taking a bolus right when I put it on).

But in this case I didn’t want to take anymore insulin right before bed, and didn’t want to cut basal since it was a new pod. So I left the basal alone. I should have cut it!

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