How Is Blood Sugar Affected By Exercise?

How Is Blood Sugar Affected By ExerciseExercise generally is seen as good for your blood sugar control overall. The exercise is moderate rather than more intense.

More intense exercise increases your blood sugar to give your muscles the energy to do this – releasing it from your liver and breaking down muscle if needed. (

Even though it spikes your blood sugar there are good long term benefits for increasing your overall health and in particular from Mark’s Daily Apple is this:

“Diabetics, take heed. Sprint training improves insulin sensitivity, improves hyperglycemia in type 2 diabetes, and lowers the postprandial glucose response in diabetics. You gotta start doing it if you’re not already.”

It helps you get faster at running too.

I decided to see the effect of running intervals on my blood sugar to see what happens, it’s also after reading this article at Steve Cooksey’s Diabetes Warrrior and his thoughts on when and why you should do intense exercise.

Each week I am doing interval training with my running club to help with my running. The session includes a warm up, some running drills, an interval session of some sort a time mile and a warm down.

How I Did The Test

It would be great to be able to test it over the whole training session but I’m not really able to do so as it might interrupt other runners and don’t have a continuous glucose monitor.

Instead, I decided I’d take my blood sugar just before the session and then straight after to see where it was at that stage and then an hour after. I’d do more to see how it went but I will likely be asleep at that stage as the session doesn’t start until 8.30 pm.

What I Want To See

I want to see how high it got after an interval session (and I might continue this on to see how it goes over a period of time over different levels of exercise too.)

I’m hoping to see it peak below 8 (144) and then drop back below 6 (108) after an hour.

The Readings Were

Before the session reading was 5.6 (about 1.5 hours after meal)

After session it was 6.0 (after warm down)

An hour later it was 6.2.

The interval part of the session was 5 X 200 m sprint with about 40 seconds recovery then after 2 minutes it was 3 X 200 m sprint with 40 second recovery followed by a mile that took me 6:59. Quite an intense session

As expected the blood sugar reading went up as expected. At least it was in a reasonable level at the end of the session. I was a bit surprised at the reading after 1 hour after where it was up I was expecting it to come down after that. If it wasn’t closed to 11.00 pm I would see was it was after another hour.

Since then I ran 5.7 k at a slower pace and thought I’d see how this affected blood sugar – it took 32:03 minutes average pace 5:34 per k.

Blood sugar before 4.7, just after 6.0, one hour later 4.8. So not bad. This was after not eating for 6 hours.

Exercise does affect your blood sugar – it increases like food as your body releases the sugar for the energy needed except it comes from your body stores

Unlike eating carbs though it does help your insulin resistance as well as other benefits you don’t get from carbohydrate.

I need to try this when I diligently try to be in diet ketosis so that I am burning fat (ketones) for energy to see what this does to my blood sugar and also overall performance too – especially as I look to do a marathon next year.

Although if this was food I’d want to call it a day with what I was eating if I got these results like this but I won’t do that with these sessions. There is lots of benefits from intense exercise with better control overall.

But according to this article from 2002 very little research has been done on the effects on people with Type 2 Diabetes because they are unlikely to do it.

No wonder the ADA has a bad reputation, with those who control their blood sugar with diet and exercise.. It says ”
Very little research has been done in persons with type 2 diabetes, as most are unlikely to perform strenuous exercise.”

What a thing to conclude, so I will continue on with my experiment to see how my blood sugar responds.

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