Why Do I Have Low Blood Sugar in the Morning?

Medically reviewed by Stacy Sampson, DO on October 2, 2017Written by Natalie Olsen, RD, LD, ACSM EP-C on October 2, 2017

 

Your body uses blood sugar, called glucose, as a source of energy for cells and organs. Low blood sugar, also called hypoglycemia, happens when your body doesn’t have enough glucose to use for energy.

People with diabetes mellitus may have low blood sugar in the morning due to too much long-acting insulin, also called background insulin and basal insulin. Insulin helps to manage blood sugar by allowing glucose to enter your cells, where it can be turned into energy. Too much insulin of any kind can cause low blood sugar. Some noninsulin medications to treat type 2 diabetes mellitus can cause hypoglycemia also.

People without diabetes can also have low blood sugar, known as non-diabetic hypoglycemia. This is usually caused by lifestyle factors, such as diet and exercise habits.

Low blood sugar is usually defined as a glucose reading below 70 milligrams per deciliter (mg/dL). Readings below 54 mg/dL are more significant and signal that you may need immediate medical treatment.

What are the symptoms of low blood sugar in the morning?

If you have low blood sugar in the morning, you may wake up with some of these symptoms:

  • headache
  • sweating
  • dry mouth
  • nausea
  • lightheadedness
  • dizziness
  • shaking
  • hunger
  • anxiety
  • blurred vision
  • pounding heart beat

If your blood sugar dips below 54 mg/dL, you might have more severe symptoms, including:

  • fainting
  • seizures
  • coma

If you have any of these severe symptoms, get medical help as soon as possible. Extremely low blood sugar can be life-threatening.

What causes low blood sugar in the morning?

The causes of low blood sugar in the morning vary. If you have diabetes, you likely need to adjust your background insulin levels. Make sure you’re aware of how any other medications you take can affect your blood sugar. Your doctor can help you make sure that your insulin dosage and any other medications you take are a good fit with your diet and exercise routines. Additionally, alcohol usage is a risk for hypoglycemia.

If you don’t have diabetes, hypoglycemia is less likely to occur. However, some non-diabetes-related causes of hypoglycemia include the following:

  • drinking too much alcohol the previous night, which makes it harder for your liver to release glucose into your blood, thus causing a low blood sugar
  • chronic starvation
  • severe liver disease
  • certain diseases involving the pancreas

How can I treat low blood sugar in the morning?

Treating low blood sugar is fairly simple. If you wake up with hypoglycemia symptoms, try to consume about 15 grams of carbohydrates as soon as possible. Snacks that provide this include:

  • 3 glucose tablets
  • 1/2 cup of non-sugar-free fruit juice
  • 1 tablespoon of honey
  • 1/2 can of non-diet soda

Make sure you don’t eat too much to treat low blood sugar, as this can have an opposite affect and make your levels too high. Wait 15 minutes after your first snack. If you’re not feeling better, have another 15 grams of carbohydrates. Pairing your carbohydrate with a protein and healthy source of fat, such as nuts, seeds, cheese, or hummus, helps to keep you full and prevent another big drop in blood sugar.

If you have diabetes, work with your doctor to adjust your insulin levels with medication. If you don’t have diabetes, work with your doctor to try to figure out the underlying cause of your morning hypoglycemia.

How can I prevent low blood sugar in the morning?

If you have diabetes, make sure you regularly check your glucose levels, especially before bed. If your blood sugar regularly dips while you sleep, consider using a continuous glucose monitoring device, which alerts you when your blood sugar goes too low or too high. Try to follow these guidelines for healthy glucose levels:

  • before breakfast: 70–130 mg/dL
  • before lunch, dinner, or a snack: 70–130 mg/dL
  • two hours after meals: under 180 mg/dL
  • bedtime: 90–150 mg/dL

If you don’t have diabetes but experience regular hypoglycemia, you may also want to periodically check your glucose levels. Try to keep your glucose level from dropping below 100 mg/dL throughout the day and before bed.

Whether or not you have diabetes, follow these tips to avoid waking up with low blood sugar:

  • Eat balanced meals with healthy carbohydrates, proteins, and fats regularly throughout the day.
  • Have a bedtime snack.
  • If you drink alcohol, avoid excessive intake and have a snack with it.
  • Avoid exercising too much at night.

For a bedtime snack, try these suggestions:

  • 1 apple with 1 tablespoon of peanut butter
  • 1 ounce of cheese and a small handful of whole-grain crackers
  • one 8-ounce glass of milk
  • 1/2 avocado spread on a piece of whole-grain toast
  • handful of berries with a small handful of nuts and seeds

The bottom line

Managing hypoglycemia is fairly simple for people with and without diabetes, but you might need to try a few things before you find what works for you. If you do have diabetes, make sure you work with your doctor to make any adjustments to your medications or insulin dosing. Your physician will be able to help you find and treat the underlying cause of a low blood glucose level if it’s something you need help managing.

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