Hypoglycemia Symptoms: Low Blood Sugar Warning Signs and Prevention

• Hypoglycemia, also referred to as low blood sugar, occurs when blood glucose levels fall below the normal range, meaning cells don't have enough energy to function.
• Symptoms vary, and some cases don't present symptoms, which is why individuals with conditions like diabetes should monitor their blood glucose levels.
• Low blood sugar is treatable, especially when caught early, and future episodes can be prevented.

Most of us have probably heard the term blood sugar before, but unless someone has a relevant medical condition, such as diabetes , they probably aren't familiar with taking and interpreting their blood sugar level.

Blood sugar , also called blood glucose, comes from food. Our bodies break food down into glucose, releasing most into the bloodstream. If blood sugar levels are high, the pancreas, an organ just behind the stomach, releases insulin, a hormone that helps glucose leave the bloodstream and enter cells. Once in cells, glucose becomes usable energy.

If the pancreas doesn't make enough insulin, this process is interrupted, potentially leading to severe side effects, including death. The concern is often high blood sugar, which can lead to excessive thirst, blurred vision, and feeling tired, among other effects.

Type 1 and Type 2 diabetes are the most common causes of blood sugar issues. While both are commonly associated with high blood sugar, people with diabetes may be more likely to experience low blood sugar due to certain diabetes medications or not eating enough carbs with an insulin dose. Less common medical conditions, like a tumor in the pancreas or Addison's disease (a condition marked by adrenal insufficiency), can cause disruptions too. Eating too many carbs, an inactive lifestyle, and certain medications may also interfere with blood glucose levels.

Measuring Blood Sugar

If someone has an increased risk of high or low blood sugar, their primary care doctor may recommend testing blood sugar levels regularly. You can do this with a blood sugar meter, a small device that can be used at home or on the go. To use a blood sugar meter :

1. Make sure the meter is charged
2. Wash your hands with soap, drying them before taking the test
3. Use the meter's lancet to prick a finger
4. Squeeze blood from the finger onto the test strip

After a few seconds, a blood sugar reading will appear. The CDC provides two recommended ranges: 80 to 130 mg/​dL before a meal and less than 180 mg/​d two hours after a meal.

How often someone measures their blood sugar depends on what medical conditions they have, though it can be taken:

• When someone wakes up
• Before a meal
• Two hours after a meal
• Bedtime
• Before physical activity
• After physical activity

Anytime blood sugar is less than 70 mg/​dL , it's considered low. While high blood sugar is more common, low blood sugar symptoms are more dangerous. Low blood sugar occurs when there's not enough glucose in the bloodstream, either due to high insulin production, slow glucose production, or the body using up glucose too quickly.

Causes of Hypoglycemia

Someone can have low blood sugar for many reasons, though most affected individuals have diabetes or another medical condition that requires them to take insulin. When this is the case, common causes include :

• Taking certain diabetes medications
• Not eating enough carbs for an insulin dose
• Taking too much insulin
• Intense exercise that doesn't align with the timing someone last took insulin or ate
• Unexpected changes to when someone eats

Other causes of low blood glucose , regardless of whether someone has a related medical condition, are:

• Drinking alcohol in large quantities or without eating first
• A tumor in the pancreas
• Lack of cortisol, thyroid, or growth hormones
• Severe failure of the heart, lungs, or kidneys
• Weight loss surgeries (usually occurs more than five years after the operation)
• Certain medications, such as antibiotics and heart medications

While anyone can experience low blood sugar, it's most common in those with type 1 diabetes. In fact, type 1 diabetics experience low blood sugar up to twice a week .

Symptoms of low blood sugar are often divided into a few main types: early warning signs, more severe signs, and hypoglycemia complications.

Phase 1: Early Warning Signs

Everyone reacts to low blood sugar glucose differently, though common warnings include:

• Shaking or trembling
• Fast heartbeat
• Confusion
• Irritability
• Hunger
• Sweating
• Anxiety

Phase 2: Later Signs

Should a low blood sugar episode progress, symptoms become more serious. Severe low blood sugar symptoms include:

• Headaches
• Extreme confusion
• Dizziness
• Difficulty speaking
• Nausea
• Numbness
• Tingling skin
• Extreme hunger

These symptoms typically don't occur until blood sugar is below 54 mg/​dL , though it is also possible to dip below that threshold and have no symptoms. If a blood glucose meter reports blood sugar below 54 mg/​dL, seek immediate treatment, regardless of whether symptoms are present or not.

Phase 3: Hypoglycemia Complications

Severe low blood sugar means your body isn't getting enough energy to vital organs, including the brain. When left untreated, low blood glucose levels may result in seizures or brain damage. It can also cause your body to shut down, something known as an insulin shock. During insulin shock , someone is unconscious and may end up in a coma.

Because complications are quite severe, it's best to head to the emergency room if blood glucose levels dip below 54 mg/​dL or symptoms do not improve after eating a snack.

Possible Additional Symptoms

In addition to common symptoms, there is also hypoglycemia unawareness and nighttime hypoglycemia, which present differently than the common phases listed above.

Hypoglycemia Unawareness

Some people experience no symptoms of low blood sugar. Symptomless hypoglycemia is referred to as hypoglycemia unawareness. Due to the lack of warning signs, those with this type are more likely to experience severe hypoglycemia.

Someone is at risk of hypoglycemia unawareness if:

• They regularly have low blood sugar
• Have had diabetes for longer than five years
• Take certain medications, including various high blood pressure medications

Nighttime Hypoglycemia

While low blood sugar can happen at any time, it's more dangerous at night since someone may not notice symptoms while asleep. Causes for a low blood sugar level at night include:

• A physically active day
• Taking too much insulin
• Drinking too much alcohol in the evening
• Skipping meals and snacks, especially in the evenings.

While some people may wake up if their blood sugar dips, not everyone will. That's why a continuous glucose monitor is recommended for those prone to nighttime hypoglycemia .

Symptoms can appear at any time blood sugar levels dip. That said, they are more common when there's a disruption to daily routine, such as a physically active day or skipping a meal. They can also stem from taking too much insulin, certain oral diabetes medications, and some other medications.

It's important to remember that symptoms look different for everyone, and some people will have symptomless low blood glucose.

Checking blood sugar levels is the only way to know if someone has hypoglycemia. You can manually check these levels with glucose meters, while continuous glucose monitors (CGM) allow the machine to regularly measure levels and alert the individual if levels are low.

If a doctor suspects symptoms stem from low blood sugar, they will instruct a patient to monitor blood sugar levels for a few days, recording the levels at specific times. Those without diagnosed diabetes will also need other tests, such as imaging or blood tests , to detect the underlying cause.

If someone suspects their blood sugar dipped, the first thing to do is check their blood sugar (if they already have a monitor). It's also recommended to eat a snack to raise blood sugar quickly. Ideally, that snack should have about 15 grams of carbohydrates . Examples include:

• Five hard candies
• One-half cup of fruit juice or non-diet soda
• 4 glucose tablets (if recommended by a doctor)
• 1 tablespoon of sugar, ideally dissolved in water
• 1 tablespoon of honey

A doctor can recommend other appropriate snacks to treat hypoglycemia, keeping in mind that too much of a snack may also be detrimental.

After eating, wait 15 minutes and check levels again. If the snack raises blood sugar to a safer range, there's nothing more to do at the moment, though the individual may want to inform their doctor. Should levels remain low, eat another snack with 15 grams of carbohydrates, wait 15 more minutes, and check again. Multiple snacks may be required if it has been a while since the last meal.

If snacks do not treat low blood sugar, contact emergency medical services. Those prone to hypoglycemia may also want to keep an emergency glucagon injection kit on hand to quickly raise blood sugar while waiting for emergency services to arrive.

What Not to Do With Hypoglycemia

When you have low blood sugar, you shouldn't inject insulin or take other diabetes medicines since they can make levels drop further. Panicking at the first signs of hypoglycemia is also counterproductive as most cases resolve with fast-acting carbs and the right treatment plan.

When someone is prone to low glucose levels, preventative measures can help them stay in a normal range:

• Following a diabetes management plan as recommended by a doctor
• Careful monitoring of blood sugar levels
• Checking blood sugar levels when exercising
• Having a snack or drinking juice right after exercising
• Asking a provider if you need a nighttime snack or should make any other changes to your routine
• Limiting alcohol to one drink a day for women, two for men

To prevent low blood sugar , it's also important that an individual and their family and friends understand the warning signs and what to do if levels drop. A diabetes care team or other healthcare provider can help with this care plan.

If levels are regularly low, you may want to talk to a healthcare provider about how many carbs you should be eating, if you're on the right medications, and to review the right way to inject insulin.

Preventing Diabetes

If someone doesn't already have diabetes but experiences low or high blood sugar, they may want to take some steps to prevent type 2 diabetes , such as:

• Maintain a healthy weight
• Eat healthy, balanced meals
• Swap sweetened drinks for water
• Eat smaller portions
• Exercise regularly

What to eat when your blood sugar is low?

When blood sugar is low, it's best to eat 15 grams of fast-acting carbs. Sources of these carbs could include glucose tablets, sugar dissolved in water, hard candies, honey, and fruit juice. A doctor can help determine the right snacks for an individual.

What can be mistaken for hypoglycemia?

Hypoglycemia can be mistaken for anxiety, a panic attack, heart problems, or hyperthyroidism. The only way to know if low blood sugar is responsible for symptoms is to check blood sugar levels with a meter or continuous glucose monitor.

What happens if blood sugar is too low?

People with diabetes and other causes of regularly low blood sugar should have a treatment plan in place for any dips. That plan often includes eating 15 grams of carbohydrates if blood sugar drops and then rechecking levels after 15 minutes. If not within the normal range, they may eat another snack. When snacks don't work or someone experiences severe low blood sugar, contact emergency services.

What's the difference between hypoglycemia and hyperglycemia?

Hypoglycemia refers to when blood sugar is low while hyperglycemia is when blood sugar levels are too high.