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Low Blood Sugar or High Blood Sugar? How to Tell the Difference

Updated: Aug 25, 2023

If you’ve been diagnosed with prediabetes, you’re worried about your blood sugar being too high. And while that’s definitely an important issue for prediabetes, it’s not the only concern.

Low blood sugar can also be a problem. Let me explain…

Healthy Blood Sugar Patterns

First, let’s look at healthy blood sugar patterns. It’s totally normal for your blood sugar to rise and fall. It’s part of the process of turning your food into energy that your cells can use.

When you eat, the carbohydrates in your food are converted into glucose and sent into your blood. When this happens, your body releases the hormone insulin. This hormone’s job is to shuttle the glucose (sugar) from your blood into your cells.

A healthy blood sugar pattern looks like this:

You eat

Your body converts the carbohydrates in your food into glucose

The glucose enters your bloodstream, raising your blood sugar

Your body releases insulin that escorts the glucose into your cells where it can be used as energy or stored as fat

Your blood sugar goes down.

This pattern is normal and healthy. If you were to graph this blood sugar pattern, it would look like gentle, rolling waves. Blood glucose rises slightly after eating, then dips back down as the glucose leaves the blood and enters the cells.

Unhealthy Blood Sugar Patterns

For someone with prediabetes, your blood glucose patterns are a little bit different.

The process works the same. But there’s a hiccup. Your body still converts carbohydrates into glucose and releases insulin, but then the problems start.

If you have prediabetes, you likely also have insulin resistance. This doesn’t mean you don’t have enough insulin. But the insulin isn’t able to do its job effectively because your cells are resistant to it.

Think of it this way. Your insulin is the key that unlocks the door to the cell so the glucose can get in. But when you are insulin resistant, the door doesn’t unlock as easily. So the body produces more insulin.

Remember our blood sugar graph with gently rolling waves? When you have prediabetes those waves turn into spikes. When your blood glucose rises, it gets higher than it should because your body isn’t able to get it into the cells quickly enough.

Then when it lowers, it goes lower than it should because your body has had to release extra insulin in order to get the glucose into the cells. In a sense, it overcorrects.

How can you tell what’s going on with your blood sugar?

The most reliable way to know for sure is by testing. Testing your blood sugar is easy and relatively painless. There are even apps to help you keep track. There are a few different methods of blood sugar testing I recommend. But if you aren’t ready to test yet, you can also pay attention to how you feel.

What does low blood sugar feel like?

Part of the danger of blood sugar dysregulation is that you can’t always feel when your blood sugar is out of balance. That being said, there are more noticeable symptoms for low blood sugar than there are for high blood sugar.

You may have low blood sugar (hypoglycemia) if you experience the following symptoms:

😮 Hunger or nausea

😮 Looking pale

😮 Feeling shaky

😮 Sweating

😮 Headache

😮 Fatigue

😮 An irregular or fast heartbeat

😮 Lightheadedness or dizziness

😮 Difficulty concentrating

😮 Anxiety or irritability

If you notice these symptoms, it might be time to eat something. The CDC recommends following the 15-15 rule. If your blood sugar is low, eat 15 grams of carbs and then wait 15 minutes.

It takes a few minutes for your blood sugar to stabilize, so the waiting period is important. If you overeat carbs when your blood sugar is low, you can perpetuate the spiky blood sugar pattern you are trying to interrupt.

If your blood sugar is still low after 15 minutes, eat another serving of carbs. Then once your blood sugar is back up a bit, go ahead and eat a nutritious meal to keep it balanced as you move forward with your day.

What does high blood sugar feel like?

High blood sugar (hyperglycemia) is harder to “feel”. That’s part of what makes it dangerous. Over time you may notice some symptoms. But high blood glucose doesn’t present with immediate symptoms like low blood glucose does. Symptoms of high blood sugar include:

😮 Increased thirst and/or hunger

😮 Blurred vision

😮 Frequent urination

😮 Headache

😮 Fatigue

😮 Weight loss

😮 Vaginal and skin infections

😮 Slow-healing cuts and sores

The only real way to know in the moment if you have high blood sugar is to test your blood glucose. If you have prediabetes, you should have a discussion with your doctor about when they want you to call in with high blood sugar numbers. It’s important that you don’t try to manage high blood sugar without medical supervision. If it gets too high it can be dangerous.

That being said… If your blood sugar is a little higher than it should be, exercise is a good option to bring it down. And once you exercise, your blood sugar may remain lower for as long as 24 hours.

If you want to exercise to bring down your blood glucose level, you’ll need to do an activity that raises your heart rate a bit like fast walking. But don’t try short bursts of strenuous activity as they can trigger the body’s stress response and actually raise blood sugar.

But again, if your blood sugar is consistently high, you need to talk with your practitioner.


Did you know that a steam sauna can improve blood sugar?

Yes, that’s right! And there are many other ways to improve blood sugar. Addressing prediabetes doesn’t have to be hard. Ready to improve your blood sugar without changing your diet? Sign up for my FREE mini course, 10 Ways to Improve Blood Sugar Without Changing Your Diet. It’s a free email course, and it’s a fast and easy way to learn 10 impactful tips to begin balancing your blood sugar TODAY! Learn more



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