Why Does My Blood Sugar Go Up After Exercise?

Why Does My Blood Sugar Go Up After Exercise?

Conventional wisdom tells us that exercise is good way to help control blood sugar levels and for someone with type 1 diabetes like myself, that's a great thing. Theoretically, as we exercise the body requires glucose for fuel which in turn reduces our blood glucose. Simple, right? Well, not entirely.

If you are a type 1 diabetic you may have noticed that your blood glucose level actually increases post workout. But if glucose is required for energy, how can this be? Of course, it is possible that you used a faulty insulin pen pre-workout or miscounted your carbs perhaps, but this isn't the answer to this ongoing phenomenon. The reason why your blood glucose regularly spikes after exercise comes down to workout intensity, stress hormones and the liver.

When we exercise we require energy and for high intensity training, glucose is the main source of this energy. A lot of the glucose in our body is stored in the muscles and the liver. When we exercise, the body releases stress hormones such as adrenaline and cortisol. These stress hormones signal the liver to release glucose while cortisol increases insulin resistance. The result is higher levels of sugar in the blood.

It's important to the note that the type of exercise you are performing can have a dramatic effect on your blood glucose post workout. High intensity workouts such as heavy weight lifting, sprinting or HIIT are very stressful on the body. In turn there is a significant release of stress hormones which trigger the liver to dump glucose to meet the needs of the workout. Low intensity workouts such as walking or moderate paced cycling aren't as stressful on the body so don't produce as much of these stress hormones. There isn't the same immediate output of energy so the body slowly uses the glucose that's already in your blood. In other words, the greater the exercise intensity, the greater the potential for high blood sugar post workout.

Before avoiding high intensity exercise altogether, we must remember that these potential glucose spikes are only temporary and the long term benefits of exercise can far exceed the short term annoyances. I am a big advocate of high intensity and low intensity training and both can certainly have a place in your workout schedule depending on your current fitness goals.

Once we know how exercise types can effect blood sugar we can proactively plan to counter any imbalances and avoid the unwanted stresses of seeing what may have previously been an unexpected glucose reading. Understanding the process of glucose production from the liver can even help avoid hypos without the need for a sugar snack. We must also be aware of the effect of basal, or background, insulin on the body. This basal insulin provides the body with a slow and steady release of insulin throughout the day to help control the ongoing production of glucose from the liver. Keeping our blood glucose levels within the recommended narrow range each and every day will optimise our results from exercise while helping to avoid complications of type 1 diabetes down the road.

For more information on hyperglycaemia, exercising and building muscle with type 1 diabetes, be sure to check out my "How to Build Muscle with Type 1 Diabetes" blog.

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