Symptoms of low blood sugar and their severity can vary between people. Low blood sugar can cause dizziness, jitteriness, confusion, and other symptoms.

Hypoglycemia, or low blood sugar, is often associated with diabetes. But it can also occur in people who do not have the condition.

Read on for more information about the symptoms and effects of low blood sugar on the body.

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When a person has low blood sugar, they may experience confusion and blurred vision.

Low blood sugar occurs when the amount of sugar in the blood drops below the normal range. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), doctors typically define this as 70 milligrams per deciliter (mg/dL) or less.

When low blood sugar occurs, a person may experience one or more symptoms. These can differ between people and vary in severity. According to NIDDK, mild to moderate symptoms may include:

  • hunger
  • jitters or shakiness
  • sweatiness
  • lightheaded or dizziness
  • blurry vision
  • headaches
  • fatigue or sleepiness
  • pale skin
  • confusion
  • feeling of weakness
  • nervousness
  • irritability
  • lack of coordination
  • combative or argumentative
  • irregular or fast heartbeat or pulse
  • changes in personality or behavior
  • difficulty concentrating

In severe cases, a person may experience the following symptoms:

  • seizure
  • convulsions
  • inability to eat or drink
  • loss of consciousness

Learn more about what healthy blood sugar levels look like here.

Low blood sugar is often associated with diabetes, but it can occur in people without this condition. No matter the cause, low blood sugar is dangerous, and a person should treat it as soon as possible.


People with diabetes are at risk of their blood sugar levels dropping below the normal range. According to the Centers for Disease Control and Prevention (CDC), common causes include:

  • using too much insulin
  • taking too much diabetes medication
  • increase or change in exercise
  • drinking alcohol
  • skipping a meal

The NIDDK adds that other potential causes include:

  • being sick
  • not consuming enough carbohydrates
  • delaying a meal for too long

Causes not related to diabetes

According to the Endocrine Society, non-diabetes-related hypoglycemia is rare but can occur. There are two types:

  • fasting hypoglycemia, often associated with an underlying condition
  • reactive hypoglycemia, which occurs within a few hours of a meal

Causes of fasting hypoglycemia may include:

  • binge drinking or heavy alcohol consumption
  • liver, heart, or kidney disease
  • tumors that affect the pancreas
  • low hormone levels
  • certain medications, such as salicylates (aspirin) or sulfa (antibiotics)

Causes of reactive hypoglycemia include:

  • a person with prediabetes
  • enzyme deficiency
  • stomach surgery

Doctors are still not clear about what exactly causes reactive hypoglycemia. However, they know people with this condition tend to have excessive insulin in their blood.

If a person has low blood sugar shortly after finishing a meal, they could have reactive hypoglycemia.

People recovering after recent stomach surgery may be at a higher risk of this after meals. This is because food passes through the stomach too quickly.

Similarly, people who experience pre-diabetes may notice a drop in blood sugar levels after eating because their bodies cannot regulate insulin properly.

If low blood sugar symptoms are severe, a person may need emergency care. Healthcare providers can assess people and provide treatment when needed.

People who do not have diabetes should talk to their doctor about their symptoms. Healthcare professionals should be able to diagnose low blood sugar and look into the cause.

The tests to determine these underlying causes will vary based on the person. In some instances, doctors may conduct a physical examination and blood tests.

The severity of low blood sugar symptoms determines what treatment is necessary.

In severe cases of hypoglycemia, a person may not be able to self-administer their diabetes medication, or the time has passed for the “15–15 rule”. In these instances, someone should inject the person with glucagon and call 911. They should also call 911 if glucagon is unavailable.

15–15 rule

For mild to moderate low blood sugar symptoms, the American Diabetes Association (ADA) recommend people follow the 15–15 rule:

  1. Consume 15 grams of carbohydrates.
  2. Wait 15 minutes and retest blood sugar levels.
  3. If the blood sugar is still below 70 mg/dL, repeat the process.
  4. If the blood sugar reaches 70 mg/dL, eat a small meal or snack to prevent it from dropping again.

They also recommend recording instances of blood sugar level drops and talking about them with a doctor.

Potential foods to eat or drink that contain 15 grams of carbohydrates include:

  • 4 ounces of juice or soda
  • glucose tablets
  • tablespoon of sugar or honey
  • hard candy

Immediate treatment follows the 15–15 rule for people without diabetes.

Glucagon injection

In severe cases of low blood sugar, a person will need help to get treatment. According to the NIDDK, these people will need a glucagon injection.

Steps for injecting glucagon:

  1. Inject the glucagon into the arm, thigh, or buttocks.
  2. The person should regain consciousness in 5–15 minutes. They may vomit, so make sure they are comfortable.
  3. Call a doctor or take the person to the hospital so healthcare professionals can monitor them.

People with diabetes should talk to their doctor about how to use an emergency kit. They should also regularly check the expiry date on their glucagon medicine and inspect their injection equipment for damage.

People should also educate family members and coworkers on how to administer emergency glucagon injections. If the injection does not work or the syringe is faulty, people should call 911 immediately.

If a person has consistent or regular low blood sugar levels due to diabetes or other conditions, they are at risk of developing severe complications.

According to an older study, long- and short-term complications can include:

  • changes in quality of life
  • lack of sleep
  • kidney issues
  • issues with blood flow to the brain
  • impaired cognitive function
  • heart attack
  • loss of vision
  • coma

People with diabetes who experience hypoglycemia symptoms while on a treatment plan should talk to their doctor, as their medicine or diet may need changing.

People can help prevent future occurrences of low blood sugar by making healthful lifestyle changes and diligently following a treatment schedule.

A person without diabetes should see their doctor if they experience low blood sugar symptoms. After a doctor diagnoses the underlying cause, they can design a treatment plan that may minimize or stop future symptoms.

A person should follow medical advice to help limit occurrences of low blood sugar, which can lead to serious complications. If people get these symptoms treated quickly, they can potentially avoid life-threatening situations.

If somebody experiences a sudden and severe drop in blood sugar that they cannot remedy, and they lose consciousness, people should call 911, as they could fall into a coma. They should also inject the person with glucagon immediately if this is available.

The best way to manage low blood sugar is to seek a diagnosis and make lifestyle changes to prevent symptoms from occurring.

Early detection of diabetes or any other underlying cause is important. This helps a person get on to a treatment plan before symptoms become severe.

According to the ADA, a person who experiences low blood sugar symptoms should check their blood sugar levels:

  • before and after meals
  • in the middle of the night
  • before bed
  • more frequently in response to changes in medication or lifestyle
  • before and after exercise

People may experience low blood sugar if they miss a meal or have too much insulin in the blood. Both diabetes- and non-diabetes-related hypoglycemia can cause a drop in blood sugar levels.

If a person experiences low blood sugar symptoms, they should seek a diagnosis so that treatment can begin promptly.

Prevention is vital to help stop severe symptoms from developing. Monitoring and managing blood sugar levels consistently can help prevent future complications, such as vision loss.

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