Hypoglycemia & Hyperglycemia

Detecting the signs of low blood sugar and high blood sugar

Hypoglycemia and hypoglycemia may sound similar, but they have vastly different consequences. Hypoglycemia is low blood sugar, while hyperglycemia is high blood sugar. Both conditions can create serious health problems for people with diabetes, so it is important to keep your blood sugar within a healthy range.

High and low blood sugar is most common in people with diabetes, but it can also occur in people who don’t have diabetes.

Here is everything you need to know to understand hypoglycemia and hyperglycemia, including causes, symptoms, treatment, and prevention.

Definitions and Differences

Hypoglycemia and hyperglycemia are potentially fatal conditions if not treated immediately. Therefore, it is important to understand each of these conditions if you have diabetes. Understanding the causes, symptoms, prevention, treatment, and when to seek medical help can save someone’s life.

Hypo means under, beneath, or below normal. Hyper means above, beyond, or excessive. Glycemia is the presence of glucose (sugar) in the blood.

Graphic showing different glucose levels, low blood sugar, normal blood sugar and high blood sugar

Hypoglycemia

Hypoglycemia is below normal sugar (glucose) in the blood with a fasting blood sugar of 70 mg/dL (3.9 mmol/L) or lower. For most people with diabetes, immediate treatment is required when falling below this unsafe level. The fastest treatment is anything containing glucose or dextrose, such as glucose tablets, gels, sports drinks, or hard candy. If these options aren’t readily available, then slightly slower options include regular soda or fruit juice. Carbohydrates with high-fat content, such as potato chips or donuts, are poor options as the fat slows down the absorption of carbohydrates.

Hypoglycemia has three levels:

  1. Below 70 mg/dL (3.9 mmol/L) is a moderate risk of severe complications
  2. Below 54 (3.0 mmol/L) is a high risk of severe complications
  3. Severe is when a person is incapacitated to the point of requiring assistance

Hyperglycemia

Hyperglycemia is excessive sugar (glucose) in the blood. Two different ranges are associated with hyperglycemia. The World Health Organization (WHO) defines hyperglycemia as having blood sugar greater than 126 mg/dL (7.0 mmol/L) when fasting or greater than 200 mg/dL (11.0 mmol/L) 2 hours after a meal. Although it’s not ideal to have blood sugar above these ranges, they are typically safe ranges for a person. The other range for Hyperglycemia is above 200 mg/dL (11.1 mmol/L). This is unhealthy and can lead to permanent complications if this high blood sugar level is maintained over several days or weeks.

Ketoacidosis and hyperosmolar hyperglycemic nonketotic syndrome are short-term complications from extremely high levels of blood sugar. Ketoacidosis can become significant when blood sugar is above 270 mg/dL (15 mmol/L). Hyperosmolar hyperglycemic nonketotic syndrome can be very dangerous with blood sugar above 600 mg/dL (33 mmol/L).

You should seek medical assistance if your blood sugar is persistently above 240 mg/dL (23.3 mmol/L).

Causes of Hypoglycemia and Hyperglycemia

Hypoglycemia

Hypoglycemia typically happens in people who already have diabetes. However, it is possible for someone who doesn’t have diabetes to have low blood sugar. Insulin is an essential hormone produced by the pancreas to allow sugar to enter your body’s cells. When too much insulin is in your bloodstream, your blood sugar drops to unsafe levels.

Intense or extended exercise can cause blood sugar to drop significantly. This could also happen if too much time elapses between meals, you’ve taken too much insulin, or you drink too much alcohol. Some medications can also cause your blood sugar to drop, including aspirin, birth control, blood pressure medication, antibiotics, or steroids. Other types of medications can increase the amount of insulin your pancreas creates. 

Be sure to consult your doctor about the potential risks medications pose to you if you have diabetes.

Hypoglycemia Unawareness

Hypoglycemia unawareness occurs when blood sugar falls below 70 mg/dL (3.9 mmol/L), and you don’t experience any symptoms. Hypoglycemia unawareness can develop if you become hypoglycemic too many times. This is yet another reason why it is so important to monitor and correct your blood sugar. Most often, hypoglycemia unawareness occurs in people who have had diabetes for a long time. Closely monitoring and correcting blood sugar helps prevent this condition. It is possible to regain early symptoms if you can go extended periods without reaching low levels. Your body will relearn how to react to these low levels.

It is possible to experience symptoms of hypoglycemia while having blood sugar above 70 mg/dL (3.9 mmol/L). This can happen when your blood sugar is very high but then drops down quickly. If this happens to you, discuss proper treatment with your diabetes care team.

Hyperglycemia

Hyperglycemia typically happens in people with diabetes who aren’t managing their blood sugar properly. For people with type 1 diabetes (or type 2 diabetes), this might mean medications aren’t being taken as prescribed or aren’t being taken at all. For people with type 2 diabetes, this might mean that a healthy diet, sleep, exercise, and stress management practices aren’t in place.

Other conditions that can cause hyperglycemia for both people with diabetes and nondiabetic people are infections, poor eating habits, inactivity, obesity, polycystic ovary syndrome, or Cushing’s syndrome.

Symptoms of Hypoglycemia and Hyperglycemia

Hypoglycemia

  • Hunger
  • Fatigue
  • Headache
  • Trouble concentrating
  • Sweating
  • Confusion
  • Fast heartbeat
  • Shaking
  • Irritability

Severe Hypoglycemia

  • Aggressiveness
  • Disoriented
  • Confusion
  • Seizure
  • Loss of consciousness
  • Coma

Hyperglycemia

  • Extreme thirst
  • Dry mouth
  • Frequent urination
  • Headache
  • Weakness
  • Nausea
  • Blurry vision
  • Shortness of breath
  • Confusion

Severe Hyperglycemia

  • Fruity smelling breath
  • Weakness
  • Dry mouth
  • Nausea or vomiting
  • Shortness of breath
  • Confusion
  • Abdominal pain
  • Coma

Hypoglycemia

  • Hunger
  • Fatigue
  • Headache
  • Trouble concentrating
  • Sweating
  • Confusion
  • Fast heartbeat
  • Shaking
  • Irritability

Severe Hypoglycemia

  • Aggressiveness
  • Disoriented
  • Confusion
  • Seizure
  • Loss of consciousness
  • Coma

Hyperglycemia

  • Extreme thirst
  • Dry mouth
  • Frequent urination
  • Headache
  • Weakness
  • Nausea
  • Blurry vision
  • Shortness of breath
  • Confusion

Severe Hyperglycemia

  • Fruity-smelling breath
  • Weakness
  • Dry mouth
  • Nausea or vomiting
  • Shortness of breath
  • Confusion
  • Abdominal pain
  • Coma

If you, or someone you know, are experiencing any severe symptoms from either hypoglycemia or hyperglycemia, seek immediate medical attention.

Emergency glucagon kit opened showing syringe filled with glucagon ready for injection

If a person with diabetes has hypoglycemia and loses consciousness, emergency glucagon (such as a glucagon pen) will be an important response. While waiting for medical help to arrive, administering the emergency glucagon can be life-saving for the unconscious individual. Be sure that all family members know where to locate and how to administer the glucagon.

Prevention of Hypoglycemia and Hyperglycemia

The best method of preventing hypoglycemia or hyperglycemia is through careful diabetes management. This includes regularly monitoring your blood sugar, preparing for situations that will lower or raise your blood sugar, and learning to recognize and respond to symptoms.

Monitor Your Blood Sugar

Close up view of woman checking her blood sugar using a glucometerRegularly check your blood sugar:

  • Before and after meals
  • Before and after exercise
  • During exercise (if intense or extended)
    • Middle of the night if participating in intense exercise during the day
  • Before bed
  • While you are sick
  • Changes in your routine (work, sleep, medications, exercise, etc.)
  • Changes in insulin or medication
  • While traveling

Successful prevention of hypoglycemia and hyperglycemia involves keeping a close eye on your blood sugar. Knowing what situations can potentially raise or lower your blood sugar to unsafe levels is paramount in staying safe. This is why it is so important to continue to educate yourself about diabetes. The more you know, the safer you become.

Through careful monitoring of blood sugar, you can make corrections before hypoglycemia or hyperglycemia take effect.

Prepare for the Unexpected

Many people do a good job regulating blood sugar at home or during structured situations that are a part of their routine. However, it is much more challenging to control your blood sugar when placed in new or uncertain situations. For this reason, taking time to think through possible scenarios and bringing appropriate items to respond can ensure safety while away from home.

For example, if you are attending a celebration but don’t plan to eat unhealthy food, it is still good to bring insulin to the event. You may change your mind or eat something that contains more carbohydrates or sugar than expected. Total Diabetes Wellness recommends having a small bag, such as a wet bag, containing all of your necessary items to help monitor and respond to your blood sugar.

Top view of healthy low carb meal for on the go or at work lunch, veggies, chicken, egg and cauliflower riceYou may be going on vacation, but don’t plan on doing any exercise while gone. However, while on a hike, you may get lost and need to exert more energy than anticipated. Or perhaps you have a unique opportunity to go on an exciting adventure or excursion that requires a lot of exercise.

Bringing items with you to help monitor and respond to rising or lowering blood sugar can help ensure your levels remain in a safe range. These items will also allow you to be flexible in your decisions while away from home.

Recognize Warning Signs

It is important that you and others are aware of signs and symptoms. Your responsibility is to know the initial warning signs so that you can respond accordingly. Being able to raise or lower your blood sugar before it reaches unsafe levels helps avoid dangerous situations.

Be sure that your family or trusted friends understand the more serious warning signs so that if you become disoriented, they can help. They can check your blood sugar, so they know how to best respond and help you. This may help prevent you from losing consciousness or falling into a coma. If, for some reason, however, you lose consciousness and are unable to respond, someone else will need to respond appropriately. Make sure they know what to do in this type of situation.

Have a Plan

Ideally, all plans go as planned, and no emergencies arise. However, it is important to have a plan, just in case an emergency does take place.

Other people should know how to access your plan. Don’t expect them to remember what to do in the case of an emergency. This is an unfair and unsafe expectation to place upon them. Be sure that your plan is readily accessible and doesn’t involve figuring out what to do on their end.

If you know that you will participate in activities that can raise or lower your blood sugar, it may be wise to practice responding. For example, if you have a glucagon pen, show them where it is and how to use it.

Treatment of Hypoglycemia and Hyperglycemia

Hypoglycemia

Use the 15-15 rule. Eat or drink 15 grams of carbohydrates (glucose tablets, 1 tablespoon of sugar or honey, sugar candies) to raise your blood sugar. Check it after 15 minutes. If you are still below 70 mmol/L (3.9 mmol/L), repeat this cycle. Continue to do this until you are over 70 mmol/L (3.9 mmol/L). Once you are above this range, you will want to consider eating something slower-acting to help raise and sustain your blood sugar to a safer range.

Be sure to have an emergency hypoglycemia kit with you at all times and that people around know what to do in case of an emergency. If you cannot respond due to vomiting, cannot swallow/eat, or lose consciousness, have someone administer your emergency glucagon.

Hyperglycemia

Two women outside walking for exercise.If you are on insulin, you may need to take more insulin to lower your blood sugar to a safe range. Also, drink more water and make sure you don’t accidentally skip or miss any of your medications.

Go for a walk to help bring your blood sugar down. It is safe to exercise if your blood sugar is below 250 mg/dL (13.9 mmol/L). Do not exercise if your blood sugar is over 250 mg/dL (13.9 mmol/L), as it is unsafe.

If your blood sugar is over 240 mg/dL, check your urine for ketones. If ketones are present, do not exercise. Instead, contact your doctor and let them know your blood sugar is over 240 mg/dL and ketones are present, and they will be able to find the safest way for you to lower your blood sugar.

What to Do in an Emergency

Hypoglycemia

If someone is experiencing hypoglycemia and is experiencing confusion, blurry vision, or is disoriented, give them a couple of glucose tablets, a tablespoon of sugar or honey, sugar candies, or something high in sugar but low in fat (not chips or donuts) to help raise their blood sugar. Wait 15 minutes to see if conditions get better. If the symptoms are the same after 15 minutes, 

If conditions worsen or the person experiences a seizure, loses consciousness, or falls into a coma, immediately call 911 or get to the Emergency Room (ER). Administer emergency glucagon while either waiting for emergency personnel to arrive or before heading to the hospital.

If helping someone who loses consciousness, DO NOT inject insulin (will cause blood sugar to lower) or try to force them to eat or drink (can choke).

Hyperglycemia

If you are experiencing blood sugar above 240 mg/dL (23.3 mmol/L) for extended periods and ketones are present in your urine, contact your doctor immediately. 

It is important not to ignore hyperglycemia, as ketoacidosis is a life-threatening condition that can quickly develop and requires immediate emergency treatment.