Metabolic Health 8 MIN READ

Nocturnal Hypoglycemia: Symptoms and prevention

Nocturnal hypoglycemia occurs when a person’s blood glucose levels drop below 70 mg/dL when they are sleeping. Various factors like diet, exercise, alcohol consumption, and daytime blood glucose levels, play a big role in determining the symptoms of nocturnal hypoglycemia in a person.

Written by Hisham Syed

Nov 02, 2021
Nocturnal Hypoglycemia Symptoms

Here’s a scenario we would like you to assume. Your alarm didn’t go off and you woke up late. You skipped your breakfast and rushed to your workplace. As soon as you entered the office you got stuck in a long meeting that went past the lunch hour. It is now 4 p.m. and suddenly you start feeling a little bit dizzy. You haven’t eaten anything since your dinner last night and your body is starving. What you are experiencing is hypoglycemia. Luckily for you, a colleague offers you a protein bar and upon eating it you may have felt much better. 

Nocturnal Hypoglycemia Symptoms


  • Nocturnal hypoglycemia occurs when a person’s blood sugar levels drop below 70 mg/dL when they are sleeping,
  • Various factors like diet, exercise, alcohol consumption, and daytime blood glucose levels, play a big role in determining the symptoms of nocturnal hypoglycemia in a person,
  • It is recommended to check one’s blood glucose levels hourly and can be done with the help of a CGM (Continuous Glucose Monitor).

Hypoglycemia is a condition in which the glucose levels in the bloodstream drop too low. Everyone’s blood glucose levels are different at different times, depending on their fitness and diet, among other factors. However, for most people, a blood glucose level below 70 mg/dL (milligram per deciliter) is considered low. Severe hypoglycemia is labelled as ‘low blood sugar’ when there is excessive insulin in the body.

To understand this condition better, we need to learn about glucose metabolism first. Our bodies need energy, much like a machine needs fuel to run. Glucose is the main source of fuel for our cells and the amount of glucose present in our bloodstream is controlled by Insulin, a hormone created by the pancreas. Insulin helps store glucose in the liver, fat, and muscles, and regulates the body’s metabolism of carbohydrates, fats, and proteins. After eating, blood glucose levels rise and insulin helps the cells to absorb blood sugar for energy and storage. Post-absorption, glucose levels in the bloodstream begin to decline.

The pancreas then produces glucagon, a hormone that prompts the liver to break down glycogen (stored sugar) into glucose and release it into the bloodstream. This ensures stable blood glucose levels in the body and the brain. However, when these glycogen stores are depleted and there is no immediate replenishment, then the body can go into hypoglycemia. When you get hypoglycemia during the day, you are aware of it and you can take measures to remedy it. However, what about when you get hypoglycemia during the night or nocturnal hypoglycemia? To answer that, let’s first understand the mechanics of nocturnal hypoglycemia.

What is Nocturnal Hypoglycemia?

Nocturnal hypoglycemia is a medical term for hypoglycemia episodes occurring when a person sleeps and the blood glucose levels fall below 70 mg/dL, with severe cases reporting a drop in blood glucose level down to 50 mg/dL. Research suggests that approximately half of all the phases of declined blood glucose—and more than half of all severe ones—take place at night during sleep.  

Why Does Nocturnal hypoglycemia Occur?

Nocturnal hypoglycemia can occur in people who:

  • Skip meals, particularly dinner
  • Work out before bedtime
  • Drink alcohol close to bedtime
  • Have infections

Other potential causes include reported incidents of daytime hypoglycemia or an excess of insulin medication before bedtime. Children too may be at risk, becoming a cause of worry for parents who might not get ample warning before their child experiences nocturnal hypoglycemia. Some environmental factors can also be a contributor to nocturnal hypoglycemia, high altitudes, and hot and humid weather conditions can play a symptomatic role. Menstruation in women has also been suggested but not identified as the sole cause of nocturnal hypoglycemia.

Symptoms nocturnal hypoglycemia

What are the symptoms of Nocturnal Hypoglycemia?

Since nocturnal hypoglycemia usually occurs at times when the person is asleep, the condition is often asymptomatic and unrecognized. People with hypoglycemia unawareness are more likely to sleep through their episodes, thereby making it difficult to identify these symptoms early on. Low levels of blood glucose trigger the creation of epinephrine (adrenaline: the flight or fight hormone), which can lead to episodes of anxiety as well. Glucose is the fuel of the brain. If the blood sugar levels continue to drop, the brain does not get enough glucose and stops functioning as it should. In case it continues to drop to dangerous levels (<55 mg/dL), it may lead to seizures, coma, and, in rare cases, death.

Here are a few symptoms to help you in identify Nocturnal Hypoglycemia

  1. Prolonged periods of restless sleep
  2. Hot, clammy or sweaty skin
  3. Trembling or shaking
  4. Rapid changes in breathing
  5. Nightmares rousing people from their sleep
  6. Waking up with a racing heartbeat
  7. Colour draining from the skin (pallor)
  8. Hunger or nausea upon waking
  9. Seizures in bed
  10. Tingling or numbness in the face and lips

Other Factors that can Cause Nocturnal Hypoglycaemia

timings nocturnal hypoglycemia

1. Meal timings: Have you ever skipped dinner or had a very light dinner because you were trying to lose a few pounds? If you have, you must have observed that you didn’t sleep well at night and kept getting up all the time. Here’s what happened to your body when you were sleeping. When the blood glucose levels dropped, the body automatically triggered its ‘hunger’ functions which the brain understood as a biological wake-up call. When you skip dinner or eat too few calories, your blood glucose levels can drop during the night and this can cause a disruption of sleep functions, affecting the quality of rest in the long run. This is especially for people with high-performance morning routines like endurance athletes and management-level executives as well.

One of the most popular at-home ways to address nocturnal hypoglycemia is the 15-15 rule: have 15 gms of carbs to raise your blood glucose and track it every 15 minutes. If the glucose levels are still below 70 mg/dL, it is recommended to consume another 15 gms of carbs. Eating a light but fulfilling dinner is also recommended in stabilizing the glucose levels during the night.

If you have symptoms of nocturnal hypoglycemia then stick to healthy eating habits. This should include a variety of fruits, vegetables, and lean proteins. The fibre in plant foods, along with lean protein, will give you lasting energy and won’t crash your blood sugar. If you plan to eat or drink something sweet, do so as part of a balanced meal. It is recommended that you consume a carb-inclusive meal immediately after an episode of nocturnal hypoglycaemia.

Alcohol consumption hypoglycemia

2. Alcohol consumption: People who consume alcohol regularly, especially in the evenings or closer to bedtime, should track their blood glucose levels. Alcohol initially leads to a spike in glucose levels, which is generally metabolised speedily. However, if you drink alcohol on an empty stomach or after a rigorous workout or if you have much more than a couple of drinks then, the glucose levels can dip sharply. To explain this further, one of the key functions of the liver is to produce glucose through glycogenolysis (turning glycogen into glucose) or gluconeogenesis (manufacturing necessary glucose by harvesting amino acids, waste products and fat by-products).

Tips to Prevent Nocturnal Hypoglycemia at Night

It is very important to identify the symptoms of nocturnal hypoglycemia early on to avoid serious symptoms or damage to biological functioning. So, let’s begin with what an ideal glucose range should look like:

  • Above 70 mg/dL to 110 mg/dl: optimum for smooth physiological functioning.
  • Below 70 mg/dL: onset of mild hypoglycemia, symptoms of nocturnal hypoglycemia.
  • 55 mg/dL and below: risk of severe daytime and nocturnal hypoglycemia.

If an individual has had symptoms of nocturnal hypoglycemia in the past then it is recommended to have a set routine that involves hydrating oneself upon waking up and consuming breakfast post morning ablutions. It is recommended to check one’s blood glucose levels hourly and can be done with the help of a CGM (Continuous Glucose Monitor). This nifty contraption can sound an alarm when a person’s blood glucose levels fall too low—ideal for identifying both hypoglycemia unawareness and nocturnal hypoglycemia. One shouldn’t skip meals, especially dinner or overconsume alcohol, especially on an empty stomach. It is also important to hydrate and eat well post-rigorous workout, especially if one is working out in the evening.  

Irrespective of how these remedies may help improve a person’s condition at a given moment, it is always recommended to consult a doctor. Often the doctor will suggest changing the night and morning routines to better suit one’s eating habits and record cases of blood glucose loss during bedtime. They will work with the patient to identify what may be the cause behind them experiencing nocturnal hypoglycemia, suggesting a treatment plan that works in the long term.


Nocturnal hypoglycemia occurs when a person’s blood glucose levels drop below 70 mg/dL when they are sleeping. Various factors like diet, exercise, alcohol consumption, and daytime blood glucose levels, play a big role in determining the symptoms of nocturnal hypoglycemia in a person. Meal timings play a big role in triggering episodes of nocturnal hypoglycemia, especially if one is regularly missing meals. An episode of nocturnal hypoglycemia should be addressed immediately with the consumption of simple sugars like juice, or even simple carbs in a light meal. At the end of the day, the old phrase, “prevention is better than the cure”, stands quite true for nocturnal hypoglycemia. Daily tracking of blood glucose levels, making routine changes to one’s diet (after consulting your healthcare professional), and understanding the reason behind one’s condition is a big steps toward long-term management and treatment of nocturnal hypoglycemia. 
Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new health care regimen including making any dietary or lifestyle changes.


  1. Hypoglycemia (Low Blood Sugar)
  2. Hypoglycemia: Nocturnal
  3. The risks of nocturnal hypoglycaemia in insulin-treated diabetes
  4. Mechanisms of hypoglycemia unawareness and implications in diabetic patients
  5. Melatonin & Metabolic Health

Subscribe to Metablog

Get the best, most science backed, and latest in metabolic health delivered to your inbox each week.

Thank you for subscribing!

Please check your email for confirmation message.

    You can unsubscribe at any time, no hard feelings. Privacy Policy

    Loading please wait...