You can have high blood sugar levels without diabetes, especially after eating sugary foods. A high glucose level is above 100 milligrams per deciliter (mg/dL) fasting for those without diabetes or 140 mg/dL within 2 hours of eating.

High blood sugar isn’t a condition that’s limited to people with diabetes. Blood glucose levels constantly fluctuate depending on what you’re doing, what you’ve been eating, and other processes in your body.

This article will review why your blood glucose levels can get high even without diabetes, how high is too high, and how it may feel to have high blood sugar levels.

Everything you eat or drink is broken into the most basic possible substance for your body to use as energy. This basic substance, called “glucose,” is your body’s main source of energy.

Glucose is measured by its concentration in your bloodstream because your blood carries glucose, oxygen, and other critical substances to the organs and tissues throughout your body.

For most people without diabetes, a normal blood glucose range falls somewhere between 70 mg/dL and 100 mg/dL between meals. This range is called your “fasting blood glucose level.”

Even without diabetes, it’s not unusual for your blood glucose levels to spike above the normal range at certain times. In fact, an increase in blood glucose levels is a normal response after eating a meal.

After you eat, there’s more glucose available for your body to use. Some glucose is used right away and some is stored for later, but, while your body processes this new supply of energy, it will circulate in your bloodstream.

Your blood glucose level after a meal is referred to as your “postprandial blood glucose level.” For people without diabetes, a typical post-meal blood glucose reading is about 140 mg/dL or less about 2 hours after a meal.

Anyone can feel the effects of high blood glucose levels, even people without diabetes. Sometimes the effects are called a “sugar rush.” High blood glucose levels can lead to symptoms such as:

  • increased thirst
  • blurry vision
  • dry skin
  • weakness
  • increased urination

You may also notice an increase in your energy or alertness, but this feeling is short-lived.

Foods and drinks that are high in sugar can increase your blood glucose levels well above the typical postprandial level, but this spike is usually followed by a sharp drop. The “crash” after a sugar high can come about 1 hour after your meal or snack and cause feelings of tiredness or a lack of energy.

When should you consult with a doctor if you have high blood sugar symptoms?

While it’s not uncommon to feel symptoms of high blood glucose levels after a particularly sugary meal, snack, or drink, you shouldn’t have excessive spikes in your blood glucose after a typical, balanced meal.

If you experience symptoms of high blood glucose levels after every meal, you may want to talk with a healthcare professional about your risk of diabetes or other difficulties with your blood glucose levels.

If you have diabetes but the condition hasn’t been diagnosed, you could develop severe complications of high blood glucose, such as diabetic ketoacidosis and hyperosmolar hyperglycemia syndrome.

If you develop dangerously high blood sugar levels, you may experience symptoms such as:

  • changes in your breathing
  • a fruity odor to your breath
  • vomiting and abdomen pains

There are also issues that can develop with your pancreas, adrenal glands, or insulin production that could change the way your body processes glucose.

The earlier you relay concerning symptoms to a healthcare professional, the sooner you can get the condition accurately diagnosed and receive treatment.

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The foods you do or don’t eat aren’t the only factors that can shift your blood glucose levels. Like many other processes in the body, your mental state can affect the way your body uses glucose.

High levels of stress or anxiety can affect your blood glucose levels in several ways, such as:

  • increasing your glucose level directly
  • decreasing the effect of insulin on your body’s blood glucose levels
  • reducing insulin production or release

All these processes can affect blood glucose levels and lead to a state of hyperglycemia — with or without diabetes.

Beyond stress and anxiety, there are also other medical conditions and circumstances that can alter your normal blood glucose levels.

Some examples of conditions or situations that can increase your blood glucose levels or reduce your body’s ability to control glucose metabolism include:

Diagnosis of these conditions or complications is important, especially when you’re having other medical difficulties alongside high blood glucose.

High blood sugar is related to an increased risk of complications or can even be fatal for people who are ill enough to require treatment in the intensive care unit.

Anyone can have high blood glucose levels, especially after eating or drinking something that’s very sugary.

For people who don’t have diabetes, blood glucose levels return to the normal range after meals within 1 or 2 hours. People with diabetes often require treatment with insulin or other medications to create this balance.

Increased thirst, increased urination, and a burst of energy can all be symptoms of high blood sugar, even in people who don’t have diabetes. If you experience extreme versions of these symptoms, or you feel like your blood sugar is high after every meal, talk with a healthcare professional.

Diabetes is just one of the conditions that may contribute to high blood glucose levels.