Glucose, or blood sugar, is a simple type of carbohydrate. If your blood sugar levels dip too low (hypoglycemia) or grow too high (hyperglycemia), they can affect your body’s everyday functioning.

Glucose is the simplest type of carbohydrate (carb), making it a monosaccharide, meaning “one sugar.”

Other monosaccharides include fructose, galactose, and ribose. In this form, dietary glucose and other carbohydrates eventually convert to blood glucose in the body.

Along with fat and protein, glucose is one of the body’s primary fuel sources.

People can get glucose from complex and simple carb sources. Below are some examples of each:

white bread, rice, and pastabrown rice
table sugarwhole grains

Carbs are considered either simple or complex based on how fast the body digests the sugar.

According to the American Heart Association, the body digests complex carbs more slowly, and they supply a more steady energy source. This makes them the healthier option.

Unmanaged glucose levels may have permanent and severe effects.

Your body ideally uses glucose multiple times a day.

When you eat, it quickly starts working to process glucose and other carbohydrates. Then, enzymes begin to break them down with help from the pancreas.

The pancreas, which produces hormones like insulin, is essential to how your body deals with glucose, per 2021 research. When you eat, your body tells the pancreas to release insulin to manage the rising blood sugar level.

Muscle, fat, and other cells then use glucose for energy or store it as fat for later use.

Diabetes might happen when the pancreas doesn’t produce insulin the way it should. In this case, you may need outside help (insulin injections) to process and regulate glucose in the body.

A 2018 review suggests that diabetes may also occur from insulin resistance. This is when the body’s cells do not sense insulin, and too much sugar remains in the bloodstream.

When the body does not respond to insulin the way it should, it stops glucose from entering your cells and being used for energy. Your cells respond by signaling the creation of ketones, which occurs at night and during fasting or dieting.

Over time, with insulin resistance, your insulin levels may become low, according to the American Diabetes Association (ADA). Your body may also release fat from fat cells. In addition, the liver keeps releasing more ketones, lowering your blood pH to an acidic level.

When your body cannot use glucose like it needs to, the buildup of ketones and change in blood pH may become dangerous, per the ADA. This event is known as ketoacidosis. It is a severe, life threatening complication of diabetes that requires immediate medical treatment.

Ketogenic diet and diabetes

The keto diet has gained popularity, but it’s a medical diet with risks. According to a 2019 study, a low carb or keto diet may reduce body weight, but people with diabetes and taking certain medications may have an increased risk of developing ketoacidosis.

Everyone may experience other adverse effects, such as high cholesterol, which is associated with cardiovascular disease. It’s best to speak with your doctor before starting any diet plan in order to help prevent complications.

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According to the ADA, monitoring glucose levels is important for people with diabetes. The needs and goals of each person with diabetes should dictate how often and when they check their blood sugar level.

To stay on top of your glucose levels, talk with your doctor about when and how frequently you should check your levels. Your doctor may suggest checking the levels:

  • before and after meals
  • before and after exercise
  • during long or intense exercise
  • before bedtime
  • when starting new medications or a new insulin schedule
  • when starting a new work schedule
  • when traveling across time zones

Speaking with your doctor helps set glucose level goals since they depend on your condition and other factors like age and health history.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says a simple blood test is one of the most common ways to test glucose at home when living with diabetes. You use a blood glucose meter by:

  1. Using a small lancet needle, prick the side of your fingertip to produce a drop of blood.
  2. Apply the blood to a testing strip.
  3. Place the strip into a meter.
  4. The meter shows how much glucose is in your blood at that moment.

Continuous glucose monitoring

When managing diabetes, you may want to consider speaking with your doctor about using a continuous glucose monitoring (CGM) system. The device automatically tracks your glucose 24 hours per day.

It uses a tiny sensor placed just under the skin, usually on the stomach or arm, and transmits readings to a monitor. A CGM constantly checks and records your glucose levels and alerts you when it gets too high or low.

Per to the NIDDK, the benefits of the device include:

  • needs fewer finger pricks
  • helps better manage glucose
  • leads to fewer emergencies

According to the NIDDK, most people using a CGM are living with type 1 diabetes. But experts are working on how it might help others, such as those with type 2 diabetes.

Maintaining glucose levels near the expected range is vital to keeping your body running its best. People living with diabetes may need to be even more diligent.

A 2021 review suggests a blood glucose level of less than 100 mg/dL on an empty stomach for people without diabetes. It should be less than 140 mg/dL 2 hours after a meal.

As mentioned, the target glucose levels are different for people with diabetes since they are adjusted for a person’s individual situation. Your doctor will work with you to come up with treatment goals.

The Centers for Disease Control and Prevention (CDC) suggests several reasons blood sugar levels may rise. Some triggers include:

  • Sunburn: The pain from sunburn causes stress, which might increase blood glucose levels.
  • Coffee: Even black coffee may cause you to become extra sensitive to caffeine increasing blood glucose.
  • Skipping breakfast: Missing your morning meal might raise your blood sugar after lunch and dinner.
  • Time of day: As your day goes on, your body’s ability to manage glucose becomes more difficult. Early in the morning, the surge of hormones might cause a spike in blood sugar, called the dawn phenomenon.
  • Medications: Certain medications and nose sprays may trigger your liver to create more glucose or prevent insulin production.
  • Stress: Excessive worrying and pressure might increase blood glucose levels.

These are just a few possible triggers. Illness and activity are two others. If you feel your blood glucose is not well-managed, try speaking with your doctor for help.

Blood sugar that is too low is called hypoglycemia, and blood sugar that is too high is called hyperglycemia.


A glucose level is too low when it dips under 70 mg/dL. This condition is also known as hypoglycemia, and it has the potential to be very serious.

There are signs to look for when your blood sugar falls. These include:

Hypoglycemia may occur as a result of taking more than your prescribed dose of certain diabetes medications. It might also happen when you eat fewer calories than your daily requirement or exercise for longer or more intensely than usual.

In some instances, it may also occur in people without diabetes.

Eating a meal or drinking juice may help increase glucose levels. Your doctor may help develop a plan for when your glucose level drops too low (and high), including having glucose supplements on hand.

If left untreated, hypoglycemia may be fatal. You may need emergency treatment when it occurs.


High blood glucose is also known as hyperglycemia. This may happen when your body lacks enough insulin or cannot use it properly.

The ADA considers blood glucose greater than 130 mg/dL before a meal to be higher than the target range. The ADA also suggests a target range of 180 mg/dL about 1–2 hours after you eat. You should talk with your doctor about target ranges specific to you.

Some symptoms of hyperglycemia to look out for include:

  • high levels of glucose in the urine
  • frequent urination
  • increased thirst

Your regular blood glucose range depends on many factors. Speaking with your doctor is best to ensure you’re within a healthy range for you.

Besides unmanaged diabetes, other causes exist for hyperglycemia. For example, stress and anxiety might lead to inconsistent management of diabetes, according to 2019 research. This can lead to more glucose in the blood.

Physical activity and diet might also help keep your blood sugar within the target range. But in certain situations, exercise is not appropriate and insulin may be needed. Talk with your doctor about how to best manage your blood sugar.

Over time, poorly managed glucose negatively affects your body. With frequently high blood glucose levels, you may start to experience the following:

Other severe complications include diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome. Both are conditions related to diabetes.

A condition known as hypoglycemia unawareness may occur with repeated episodes of low blood glucose. It causes you to stop noticing the signs of low blood glucose until it drops very low.

When it gets too low, you could experience:

  • loss of consciousness
  • coma
  • death

If you suspect you have diabetes, speak with your healthcare professional about your symptoms.

As with many medical conditions, it’s easier to deal with glucose issues before they get too much headway. Plus, healthy glucose levels are essential to keeping your body working at its best.

A nutritious, well-rounded diet, supplemented with exercise, is part of prevention and treatment plans when available. For some people, though, this isn’t enough.

People with diabetes may have trouble maintaining healthy and consistent glucose levels. If you’re living with diabetes, closely monitoring your glucose levels is an effective way to help avoid complications.

Managing your diabetes may be challenging but worth the effort.