Father checks his daughter for hyperglycemia or hypoglycemia

Hyperglycemia and hypoglycemia are blood sugar-related conditions that people living with type 1 diabetes (T1D) must be aware of.

Here, we explain hyperglycemia and hypoglycemia, how they are treated, and the risks associated with both.

Hyperglycemia: high blood sugar

What is hyperglycemia?

Hyperglycemia is the medical term for high blood sugar (high blood glucose).

People living with T1D are considered hyperglycemic if their blood sugar is higher than 130 mg/dL after not eating or drinking for at least 8 hours (called fasting hyperglycemia) or if their blood sugar is higher than 180 mg/dL two hours after a meal (called postprandial or after-meal hyperglycemia).

What causes hyperglycemia?

Hyperglycemia occurs when your body has too little insulin to use the sugar in your blood. It can also be caused by:

  • Caffeine
  • Stress
  • Illness
  • Medications (like steroids)
  • Hormone changes
  • Exercise and competitive sports

Symptoms of hyperglycemia

Symptoms of hyperglycemia, or high blood sugar, include:

  • Extreme thirst
  • Frequent urination
  • Tiredness
  • Blurry vision
  • Difficulty concentrating
  • Stomach pain, nausea, or vomiting
  • Sweet-smelling or “fruity” breath
  • And others

How to treat hyperglycemia

The first thing you should do to treat hyperglycemia is take insulin based on the care plan provided by your doctor. It’s also important to drink water or other carbohydrate-free beverages while managing high blood sugar.

If your blood sugar is high for several hours or above 240 mg/dL, check your insulin pump and infusion sites to make sure everything is working properly. You also need to check for ketones to make sure you are not at risk of diabetic ketoacidosis (DKA). Learn more about ketones here.

Download our printable guide What You Need to Know About Hyperglycemia (High Blood Sugar).

Hypoglycemia: low blood sugar

What is hypoglycemia?

Hypoglycemia is the medical term for low blood sugar (low blood glucose).

A person with T1D with a blood sugar of 70 mg/dL or lower is usually considered hypoglycemic. 

Hypoglycemia is common in people with T1D. In fact, most people with T1D have several episodes of mild-to-moderate hypoglycemia (blood sugar between 55mg/dL and 70 mg/dL) a week.

What Causes hypoglycemia?

Hypoglycemia occurs for several reasons, some of which you can control and some you cannot.

Causes of hypoglycemia you can control:

  • Taking too much insulin
  • Eating too few carbs for the amount of insulin you take
  • Not timing your insulin dose correctly
  • Not carefully monitoring blood sugar when engaging in exercise or drinking alcohol

Causes of hypoglycemia you cannot control:

  • Hot and humid weather
  • Interruptions in usual schedules due to travel
  • Spending time at high altitude
  • Going through puberty
  • Having your menstrual period
  • Timing of hypoglycemia during and following exercise

Symptoms of hypoglycemia

Symptoms of hypoglycemia, or low blood sugar, include feeling:

  • Sweaty
  • Shaky or weak
  • Hungry
  • Irritability or confusion
  • And others

Severe hypoglycemia (blood sugar below 54 mg/dL) can cause additional symptoms, including difficulty walking or seeing clearly, feeling disoriented, inability to swallow, loss of consciousness, and seizures. If you are unable to swallow, lose consciousness, or have a seizure, someone must administer glucagon via syringe, nasal spray, or auto-injector pen. The person with you should then call 911.

How to treat hypoglycemia

Treating hypoglycemia is based on the care plan provided by your doctor. This often includes the use of fast-acting carbohydrates (juice, fruit snacks, glucose tablets, etc.) and closely monitoring your blood sugar.

Download our printable guide What You Need to Know About Hypoglycemia (Low Blood Sugar).


Editor’s note: How you manage your type 1 diabetes is a personal decision between you and your healthcare team. Breakthrough T1D content is for informational purposes only and is not a substitute for professional medical advice. Please contact your doctor or other qualified health provider with any questions you may have regarding type 1 diabetes or any medical condition.