What Is a Blood Sugar Crash?

A blood sugar crash refers to a sudden drop in blood sugar (glucose) levels. The body responds to sugar intake by producing and releasing insulin into the bloodstream.

Insulin is a hormone that pulls glucose into cells to be used for energy and helps keep blood sugar level within the normal range. When there is too much insulin in your blood, your blood sugar can drop below what’s normal.

A sugar crash, also called hypoglycemia, is typically characterized by a blood glucose level below 70 milligrams per deciliter (mg/dL). It’s normal to have varying blood sugar levels throughout the day, but low blood sugar can cause severe complications.

Anyone can experience a blood sugar crash, but it’s especially common in people with diabetes, whose body may not produce enough or any insulin.

Hypoglycemia that occurs in people without diabetes is called non-diabetic hypoglycemia, and there are two types: reactive hypoglycemia and fasting hypoglycemia. They can be triggered by medications, other medical conditions, and tumors.

a sick woman lying on a sofa

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What Is a Blood Sugar Crash?

A blood sugar crash, or hypoglycemia, occurs when blood glucose levels go below 70 mg/dL. A low blood sugar level triggers the release of epinephrine, also known as adrenaline, the fight-or-flight hormone. It is what can cause the symptoms of hypoglycemia.

Symptoms

Each person may react to hypoglycemia differently. The symptoms of blood sugar crash can be mild to severe and include the following:

  • Shakiness
  • Nervousness or anxiety
  • Sweating, chills, and clamminess
  • Irritability or impatience
  • Confusion
  • Fast heartbeat (tachycardia)
  • Lightheadedness or dizziness
  • Hunger
  • Nausea
  • Color draining from the skin (pallor)
  • Sleepiness
  • Weakness or lack of energy
  • Blurred or impaired vision
  • Tingling or numbness in the lips, tongue, or cheeks
  • Headaches
  • Coordination problems, clumsiness
  • Nightmares or crying out during sleep
  • Seizures

If your blood sugar level is low and continues to drop, your brain does not get enough glucose and stops functioning as it should. This can lead to blurred vision, difficulty concentrating, confusion, slurred speech, numbness, and drowsiness.

If blood sugar stays low for too long, starving the brain of glucose, it may lead to seizures, coma, and very rarely death. 

Studies have shown that people are unaware of the symptoms and seriousness of hypoglycemia. One study showed that 75% of hypoglycemia episodes detected by a continuous glucose monitor were not recognized by patients.

Diabetic Blood Sugar Crash

People with diabetes have to check their blood sugar levels often and practice healthy habits to keep their blood sugar levels in check. Unfortunately, blood sugar crashes can happen for reasons out of your control.

Causes

Low blood sugar is common in people living with type 1 diabetes, but it can also occur in people with type 2 diabetes who are taking insulin or certain medications. The average person with type 1 diabetes may experience up to two symptomatic episodes of mild low blood sugar per week.

Common causes of blood sugar crashes in people with diabetes include too much insulin or an unbalanced diet:

  • Since diabetes medications are taken to lower blood sugar, they may lower the blood sugar levels too much and lead to hypoglycemia. Accidentally injecting the wrong insulin type or injecting it directly into the muscle (instead of just under the skin) can also cause low blood sugar.
  • If someone with diabetes isn’t eating enough food or lowered their glucose intake significantly, levels will drop. Not enough carbohydrates or eating foods with less carbohydrate than usual without reducing the amount of insulin taken can contribute to hypoglycemia. Timing of insulin based on whether your carbs are from liquids or solids can affect blood sugar levels as well. Liquids are absorbed much faster than solids, so timing the insulin dose to the absorption of glucose from foods can be tricky. The composition of the meal—the amount of fat, protein, and fiber—can also affect the absorption of carbohydrates.

Treatment

The main treatment for a mild sugar crash is the 15-15 rule. It helps slowly bring blood sugar level up.

It’s never a good idea to start bingeing on sugar to raise blood sugar level. This can backfire by causing the blood sugar to spike. Instead, according to the 15-15 rule, you should eat 15 grams of carbohydrate to raise blood sugar and check your blood sugar level 15 minutes after. If it’s still below 70 mg/dL, have another serving.

Food or supplements that contain 15 mg of carbohydrate include:

  • Glucose tablets
  • Gel tube
  • 1/2 cup of juice or regular soda
  • 1 tablespoon of sugar, honey, or corn syrup
  • Hard candies, jellybeans, or gumdrops (check the food label for how many to consume)

Complex carbohydrates or foods that contain fats along with carbs (like chocolate) can slow the absorption of glucose and should not be used to treat an emergency low.

Keep track of your symptoms and low blood sugar episodes and tell your doctor. If you’re experiencing severe symptoms or symptoms aren’t improving with treatment, you should call your healthcare provider or 911 immediately.

Prevention

Monitoring your blood sugar is the tried and true method for preventing hypoglycemia. The more a person checks blood sugar, the lower their risk of hypoglycemia. This is because you can see when blood sugar levels are dropping and treat it before it gets too low.

If you have diabetes, check your blood sugar at the following times:

  • Before and after meals
  • Before and after exercise (or during, if it’s a long or intense session)
  • Before bed
  • In the middle of the night after intense exercise

You should check your blood sugar more often if you made certain changes, such as a new insulin routine, a different work schedule, an increase in physical activity, or travel across time zones.

What Is a Continuous Glucose Monitor?

Besides a glucometer, you can also monitor your blood sugar with a continuous glucose monitor. These monitors are devices connected to the body all day, allowing quick access to information anytime you need it. These monitors help prevent surprise highs or lows in blood sugar and address them quickly.

There are other things you can do to avoid blood sugar crash if you have diabetes, including:

  • Eating a balanced diet
  • Avoiding sugary foods and drinks outside of mealtimes
  • Eating small portions
  • Avoiding restricting or cutting out full food groups
  • Planning ahead
  • Keeping your doctor in the know

Non-Diabetic Blood Sugar Crash

Non-diabetic blood sugar crashes are considered much rarer than diabetic blood sugar crashes. They may occur for various reasons.

Causes

There are two types of non-diabetic hypoglycemia: reactive hypoglycemia and fasting hypoglycemia. Reactive hypoglycemia, also called postprandial hypoglycemia, happens after a meal, typically a few hours later.

Possible causes of reactive hypoglycemia include:

  • Prediabetes or high risk for diabetes
  • Stomach surgery, which can make food pass too quickly into the small intestine
  • Rare enzyme deficiencies that make it hard for your body to break down food

On the other hand, fasting hypoglycemia can be caused by:

  • Certain medications, such as salicylates (including aspirin), sulfa drugs (an antibiotic), pentamidine (to treat a serious kind of pneumonia), and quinine (to treat malaria)
  • Alcohol, especially with binge drinking
  • Serious illnesses, such as those affecting the liver, heart, or kidneys
  • Low levels of certain hormones, such as cortisol, growth hormone, glucagon, or epinephrine
  • Tumors, such as a tumor in the pancreas, which produces insulin

Another uncommon cause is dumping syndrome, which causes the body to release excess insulin after eating a carbohydrate-filled meal.

Treatment

For people without diabetes, treatment depends on the cause of the hypoglycemia. For example, if you have a tumor that is causing your hypoglycemia, you may need surgery. If medicine is the cause, you need to switch to different medications. To treat your symptoms immediately, eat or drink 15 grams of carbohydrate.

A reactive hypoglycemia episode may be a sign the person has or may develop diabetes. You should discuss it with your doctor to determine your next steps.

Prevention

By making small tweaks to your diet, you can help avoid hypoglycemia. These changes include eating a balanced diet, eating less sugar and carbs, and eating more protein and fiber.

Another prevention tip is carrying a snack with you that can be used to raise your blood sugar. These snacks can include a handful of nuts, a hardboiled egg, or air-popped popcorn.

Tips for Keeping Blood Sugar Steady

The best way to address your personal concerns and needs is to discuss your diet, medication, and lifestyle with your healthcare team. They can diagnose any underlying conditions, adjust or change your medications, and advise you on the best ways to prevent hypoglycemia.

Tips that apply across the board to keep blood sugar stable include:

  • Eating a balanced diet
  • Keeping track of foods and symptoms
  • Staying active
  • Reducing stress
  • Addressing underlying conditions
  • Testing blood sugar consistently
  • Talking about concerns with the healthcare team
  • Keeping hydrated
  • Planning meals
  • Getting adequate sleep

People with diabetes may face more challenges when managing blood sugar levels, but it is possible to stay healthy.

Summary

People with diabetes and those without can both experience sugar crashes, but for different reasons. Monitoring your blood sugar is your best bet at preventing a sugar crash if you have been diagnosed with diabetes. If you don’t have diabetes, talk to your doctor to find out what may be causing your sugar crash and what changes you need to make.

A Word From Verywell

Whether you have a diabetes diagnosis or not, balance is key. It’s important to note that one person’s balance is not the same as the next person’s, so working with your healthcare team to find the right balance for you will help you keep your blood sugar levels steady and know what to do to address any problems that come up. While blood sugar crashes are possible, they can be avoided with healthy living and help from your healthcare provider.

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Article Sources
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  2. Östenson CG, Geelhoed-Duijvestijn P, Lahtela J, Weitgasser R, Markert Jensen M, Pedersen-Bjergaard U. Self-reported non-severe hypoglycaemic events in Europe. Diabet Med. 2014;31(1):92-101. doi:10.1111/dme.12261

  3. Hormone Health Network. Non-diabetic hypoglycemia. Updated July 2020.