High Intensity Training causing blood sugar spike

[Greg_LeMunyan]

I do HIIT training which I enjoy. I always do it with at least a 12 hour fast usually longer. My fasting blood sugar is usually 120 or less (working on that) my blood sugar repeatedly spikes to above 170. Am trying to hold back my maximum heart rate to reduce the effect. My understanding is I am creating a fight or flight response releasing cortisol and adrenaline then causing a liver dump. The spike settles out a couple of hours later but does effect my daily BS average on my CGM. Is my liver enlarged? Do I need to give up HIIT and strength training? Do I need to take some carbs before?

Thanks in advance.

[CarlKeller]

Hi Greg, this article might help as it relates to HIIT and people with diabetes and even people who don’t.

Why do my blood sugars go up with certain types of exercise?

Glucose is the fuel that is used almost exclusively during intense exercise. Because the demand for glucose is so high, the body needs to retrieve some from its storage form of glucose (glycogen). Levels of certain hormones, including adrenaline (epinephrine), increase causing blood sugars to rise seven- to eight-fold. However, glucose utilization only increases three-to four fold. Ultimately, more glucose is produced than is used. Even for people who don’t have diabetes, this causes a small rise in blood sugar during intense exercise that may persist for up to one or two hours. Insulin levels rise to bring blood sugar back to normal. However, people with type 2 diabetes may not have enough insulin, and their muscles may not use the insulin well enough, to bring sugars back down quickly. For people with type 1 diabetes, the physiological response is absent

High-intensity exercise and blood sugar levels: what you need to know

[lfod14]

If you’re only going up 50 from your fasting number with a HIIT session I’d say that’s not to bad at all. Any good workout is a big stress to the body, and a rise is expected. In most cases pre workout carbs wouldn’t do much unless they were very fast carbs like Dextrose, and then THAT would raise your sugars so you’re kinda in the same boat. I use Carb10 as a post workout carb but it can also be used pre-workout. It’s a fast digesting carb that’s made from peas and doesn’t spike your insulin/sugar. Very possible that having some more glycogen stores going into the workout could make your body create less endogenous glucose, but not 100% on that.

[ctviggen]

50 points seems high. I usually do lifting about 30 minutes and HIIT about 16 minutes, so about 50 minutes total. That’s twice per week. Do one HIIT on weekend, up to 30 minutes total, some abs, no lifting. Looking through my records, I mostly get increases in blood sugar, up to maybe 10 points. A lot of times, little to no rise, and sometimes it goes down. I work out in the morning, fasted anywhere from dinner the night before to 34 or so hours. I have coffee, either black or with a small amount of cream before my workout.

Do you also track your ketones? If so, what happens to them? Are you a type 2 diabetic? If so, do you take anything (any drug) around this time?

[Greg_LeMunyan]

I measure blood sugar, blood ketones 3 times a day and wear a CGM
Yesterday for example my Fasting BS/Ketones were 99/1.5, after exercise 176/1.2 and in the early evening 99/1.6. I work out at 5:45AM always fasted at least 12 hours. Usually do black coffee. My last Hba1c was 5.8. My goal is to get it below 5.0
Yesterday was strength training and I pushed it a bit because I had been experimenting with holding back to reduce my heart rate and hopefully my BS spike.

Looking at last weeks data, I can see my before and after exercise ketones going down, staying the same and going up. I have been Keto for 32 weeks.
The strength class I did is 45 minutes. I record exercise with an Apple Watch and another chest strap called MyZone. My peak heart rate was 163 and my average was 100.

[atomicspacebunny]

I do HIIT training which I enjoy. I always do it with at least a 12 hour fast usually longer. My fasting blood sugar is usually 120 or less (working on that) my blood sugar repeatedly spikes to above 170.

Do I need to take some carbs before?

Try some type 2 resistant starch (“…technically a carb but does not act like one…” …creates short chained fatty acids in large intestines…) and see what happens when you work out or not working out? I will bet those blood sugars would plummet if you like experimenting?

The interplay of exercise and ketosis – Part II

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Glucose and Ketones after exercise

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