What is Hypoglycemia (Low Blood Sugar)? Causes, Symptoms, Treatment, Prevention

Hypoglycemia or low blood sugar, People with diabetes are likely to develop this condition when their bodies don’t have much sugar to fuel. It is probably a serious condition in which glucose level falls below 4 mmol/L (72mg/dL). You may have heard about ‘insulin shock’ if you or your family member has diabetes.

A type of sugar, glucose is the most vital fuel for your body. Sugar is released when food is digested and it is absorbed as glucose in your bloodstream. Especially your nervous system and brain, your body requires a specific glucose level to work, though not too much or too less. If you have diabetes, you may experience low blood sugar if you don’t eat enough or take insulin in high amount. There are several causes of hypoglycemia, such as diet, exercise, and some conditions and medications.

If you develop hypoglycemia, note down the time and date when it happened and your activities. Share this information to your doctor so they can decide your schedule and change in medications. If you have several unexplained reactions in a week, talk to your doctor.

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What are the Symptoms of Hypoglycemia?


Most people may feel symptoms of low blood sugar when it goes below 72mg/dL (milligrams per deciliter). Different patients may have different symptoms. But here are some of the early symptoms –

  • Dizziness
  • Confusion
  • Hunger
  • Feeling shaky
  • Irritability
  • Headache
  • Racing heart
  • Sweating
  • Pale skin
  • Weakness
  • Trembling
  • Anxiety

You might get more severe symptoms if it is not treated, such as –

  • Lack of concentration
  • Impaired coordination
  • Numbness in tongue and mouth
  • Bad dreams or nightmares
  • Passing out
  • Coma

What are the causes of Hypoglycemia?

Diabetes and Low Blood Sugar

Diabetes affects the ability of your body to use insulin, which is considered as the key to unlock your cells and allow glucose for energy. People with diabetes consider different treatments to get glucose flowing in their blood. Usually, these are oral medications to promote insulin generation and injections.

When you are on such treatments, alcohol can also cause low blood sugar, especially when it is replaced by food. It goes worse in managing blood sugar. If you overdose these medicines, blood sugar level may drop too low. People often feel low blood sugar when eating a heavy meal. Eating less, skipping meals, or eating later than usual but taking medicines on time can also cause low blood sugar. Excess and unplanned exercise without having enough means can also lower blood sugar levels.

Other Causes

Diabetes is not the only cause of low blood sugar. Here are some of the other causes –

  • Some medical conditions like kidney disorders or hepatitis
  • Certain medications like quinine
  • Tumor which generates excess insulin
  • Adrenal gland deficiency and other endocrine disorders

Drugs for Diabetes Causing Hypoglycemia

If any of your medications are likely to cause hypoglycemia, ask your doctor. Treatment for insulin may also be the cause, such as sulfonylureas, a kind of diabetes medications. Here are some types of commonly used sulfonylureas –

  • Glipizide (Glucotrol)
  • Glimepiride (Amaryl)
  • Gilbenclamide (Micronase)
  • Gliclazide

Here are some of the less common sulfonylureas which may cause less blood sugar –

  • Nateglinide (Starlix)
  • Chlorpropamide (Diabinese)
  • Tolazamide (Tolinase)
  • Repaglinide (Prandin)
  • Tolbutamide (orinase)

If you take aspirin, warfarin (Coumadin), probenecid (Probalan), Benemid, or allopurinol (Zyloprim) with medications for diabetes, you may also develop low blood sugar. If you take alpha-glucosidase inhibitors, thiazolidinediones, and biguanides (i.e. metformin), you are not recommended to get hypoglycemia.


Another possible cause is taking too much insulin against the amount of carbohydrates you drink or eat. For example,

  • After having meal which has a lot of sugars
  • If you eat later
  • If you don’t have full meal or miss a snack
  • If you drink alcohol without having food.

If you have diabetes, be sure not to skip meals, especially when you are on medications.

What are the Treatment of Hypoglycemia?

If you suspect you have low blood sugar and you have diabetes, be sure to get your blood sugar level checked. Do your levels drop more often after having meals which have a lot of sugars? It’s time to change your diet. Eat small meals frequently all day and avoid sugar.

If you have low blood sugar before eating, have a snack before sleep, such as more complex carbohydrate or protein.  Your doctor may notice that you consume too much insulin which increases from evening to morning. Here, doctor may reduce your dose of insulin or change the time of last dose.

In Case of Low Blood Sugar

First of all, drink or eat up to 15g of fast-acting carbohydrate like –

  • One glucose gel tube
  • 3-4 glucose tablets
  • ½ cup of fruit juice
  • 4-6 hard candy
  • ½ cup soft drink
  • ½ cup skim milk
  • 1 tbsp honey (keep it under tongue to let it absorb in the bloodstream quickly)

After 15 minutes of eating sugary food, check blood sugar. If it is still below 70mg/dL, have another serving of one of these foods. Repeat and repeat until sugar level goes normal.

In Case You Pass Out

You might pass out due to hypoglycemia. Ask someone to give a glucagon injection. It is a prescription injection to increase blood sugar and it may be required in case of severe hypoglycemia. It’s important for your friends and family members know how to give injection with low blood sugar. If you or someone you know have severe reaction, simply call emergency number or take them to the nearby hospital. Don’t give fluids, food, or insulin to the unconscious person, or they may choke.

Don’t Drive with Low Blood Sugar

It’s very threatening. If you have hypoglycemia symptoms and driving, simply pull off the road, eat sugary food, and check your blood sugar. Wait for up to 15 minutes, check blood sugar, and repeat such steps, once needed. Eat a source of carbohydrate and protein (such as cheese, peanut butter bar, or crackers) before driving. Keep a source of sugar handy in your car every time for emergencies.


To prevent low blood sugar in diabetes, you need to –

  • Stick to your meal plan
  • Eat three well spaced meals every day with prescribed snacks between meals
  • Plan your meal within 4 to 5 hours
  • Work out at least 30 minutes to 1 hour after having meals. Keep your sugar intake on track before and after workout and talk to your doctor before making any change.
  • Keep your alcohol consumption controlled and be sure to check blood sugar levels, if you drink.
  • Double check your insulin level and dose of medicines before consuming
  • Test your blood sugar as prescribed by the doctor

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