Why Does My Blood Sugar Go Up at Night? — A Detailed Guide

Braden G. Barnett, MD

2021 Dec 30

10 min read

Diabetes causes many complications when not properly managed, and one of them is high blood sugar at night. People with diabetes usually experience night high blood sugar in three phases — before they sleep, when they sleep, and after they wake up.

Also, apart from established diabetics, people can experience a blood sugar spike at night if they’re vulnerable to developing diabetes or do things that could increase their blood sugar levels just before they sleep.

The good thing about elevated blood sugar levels at night is that you can prevent it, or at the very least, reduce it with the proper management tips. This article/guide examines how to successfully maintain low blood sugar at night by throwing light on the cause of the blood sugar spikes at night, the kind of people susceptible to it, and the solutions to live healthier.

What to expect?

  • Which Set of People Have High Blood Sugar at Night?
  • The Different Stages of Night-Influenced High Blood Sugar Level
  • High Blood Sugar at Night: Symptoms
  • How to Prevent Blood Sugar Spikes at Night

Which Set of People Have High Blood Sugar at Night?

Source: CDC

High blood sugar at night is a serious complication and no different from other sugar highs. Blood spikes can affect any individual during the night and aren’t just limited to people with diabetes. In other words, while people with diabetes are the major population that suffers from blood sugar increase, other people can still experience the phenomenon.

According to a research article on PLOS Biology titled Glucotypes Reveal New Patterns of Glucose Dysregulation, high blood sugar spikes are just as common in people without diabetes as those with diabetes. The 2018 study, which involved 57 healthy respondents, showed that people who have never suffered from diabetic symptoms also experience blood sugar rise at night. The findings were contrary to the prior belief that glucose dysregulation was diabetes-related symptoms.

Healthy people suffered from a range of sugar rise with the severity ranging from low to medium to high variability. The primary cause of the spikes in healthy people was their food choice. However, the healthy respondents’ beta cells could produce enough insulin to reduce the consequences of abnormal glucose production.

It was, however, predicted that consistent high sugar consumption in healthy people will overwhelm their insulin production and leave them open to a range of conditions common with diabetes, like cardiovascular diseases.

Another set of people who’re also open to blood sugar increases at night are those with prediabetes. Prediabetic people aren’t precisely diabetic but have poor glucose tolerance. When these people eat sugary food, they experience a consistent rise in blood sugar levels due to insulin resistance.

Suppose people with prediabetes don’t adopt a health management plan and constantly consume high sugary foods. In that case, glucose will end up building in their bloodstreams, resulting in devastating blood sugar rise. People with prediabetes are at a high risk of progressing into type 2 diabetes; as such, they must follow a strict health plan.

The Different Stages of Night-Influenced High Blood Sugar Level

Source: Diabetes Self-Management

Common questions among people with diabetes or those who easily suffer high blood sugar levels include:

  • Why does blood sugar go up at night?
  • When does it happen?
  • What can I do to stop it?

There are three stages of blood glucose levels rising at night — the pre-sleep stage, the sleep stage, and the post-sleep stage.

Pre-Sleep Stage

One of the major periods when people with diabetes or those susceptible to the condition experience a high blood sugar level is the time just after dinner and before going to sleep. The majority of people who suffer from blood glucose rise at this stage barely have a diabetes management plan and don’t pay a lot of attention to the kind of meal they eat.

Blood sugar rises aggressively when there’s too much carb and sugary food in a diet, and it gets worse when such meals are taken at night — when the body is less functional and active. People with such habits may experience blood sugar rises in as little as one hour after such meals following a check with a continuous glucose monitor (CGM) — this is much worse in those that don’t engage in physical activity.

Pre-stage sleep blood sugar high can lead to many complications in people with diabetes and those already susceptible to it. Therefore, it’s best to avoid the intake of foods that may lead to blood sugar spikes at night before sleeping.

Sleep Stage

While poor meal choices and inactivity cause pre-sleep high blood glucose levels in the earlier part of the day, blood sugar rise during sleep is influenced by many factors.

Poor meal choices could ensure consistent high blood sugars from the time before sleeping up to when you fall asleep. Even if you have a management plan that helps you control your food choices, poor adherence to your diabetes medication could also trigger a rise in your blood sugar at night when sleeping.

While the two reasons already mentioned lead to a rise in blood sugar levels, another major cause of high blood sugar levels at night is if you consistently have poor night rest. Poor sleep affects your mood, glucose metabolism, appetite, and your body response to sugar. Notably, your body loses its ability to control and prevent rebound hyperglycemia, and you may fall at risk of developing diabetes conditions such as diabetic ketoacidosis.

It could also lead to more severe issues such as heart disease that develops from the damage of the coronary arteries, obstructing the proper flow of blood and nutrients. In addition, cardiovascular conditions like stroke could also be one of the after-effects of consistent blood rise at night.

Although a healthy person will generally have enough insulin sensitivity to control blood sugar spikes during sleep, people with diabetes don’t have such luxury. As such, blood rise during the sleep stage may become consistent and lead to many complications.

Take a quiz
Discover what Klinio app can do for you
Healthy diabetes meal plan crafted just for YOU
Personalized workouts with no equipment needed
Track your progress with smart tracking tools
Take quiz

Post-Sleep Stage

The American Diabetes Association (ADA) explicitly outlines the effect of post-sleep stage blood sugar high, also known as early morning hours high blood sugar condition. Most diabetics experience this stage of blood sugar rise.

High blood sugars in this stage can either occur independently or could be an extension of what happens at the sleep stage. The following sections examine the three major causes of blood rise in the sleep stage.

The Dawn Phenomenon

The dawn phenomenon, also known as the dawn effect, occurs during the early hours of a new day, around 3 a.m. up to 8 a.m. The phenomenon is characterized by an increase in blood level and occurs when the body releases hormones that your body needs to wake up. These hormones increase glucose production in the process.

For healthy people, their pancreatic beta cells produce and release insulin to counter the glucose and ensure proper balance. However, diabetics usually suffer from insulin resistance or insufficient insulin production, resulting in unhealthy blood sugar increases during this period.

Waning Insulin

Unlike the dawn phenomenon, waning insulin isn’t independent of the other stages of night blood sugar high. It’s generally an extension of the effects from the pre-sleep and sleep stages.

Waning insulin could occur if you don’t take enough long-acting insulin that should last over sleeping hours up to the new day. This lack of adequate insulin leads to hyperglycemia which may be maintained up to the morning.

Consistent hyperglycemia holds lots of consequences both medically and psychologically. Namely, uncontrolled hyperglycemia may lead to sudden mood swings, depression, and long periods of downtime that could trigger poor decisions.

Somogyi Effect

The Somogyi effect is a rare cause of post-sleep blood sugar high, but it does happen. The effect occurs due to the hyperactive response of the body to produce high blood glucose levels following too many insulin medications.

If you use an insulin pump to keep blood sugar at a very low rate, it may respond to the low glucose level by producing excessive amounts at night, sporadically increasing blood sugar levels to unhealthy ranges.

Thankfully, you can prevent the Somogyi effect by following your health and management plan religiously and not attempting to take more insulin than necessary, especially at night. Also, the condition isn’t exactly a common occurrence and is mainly triggered by unusually high insulin intake.

High Blood Sugar at Night: Symptoms

There are various indications of high blood sugar at night that you can easily watch out for if you suspect you may have the condition. You should note that you can experience high blood sugar risk even if you undergo diabetes management.

Human errors can sometimes cause people to make several mistakes that lead to sugar rise at night. In such instances, knowing the symptoms to watch out for can help them adjust better. If you experience symptoms like the following, there’s a high chance that you have high blood sugar at night:

  • Increased urination
  • Dry mouth
  • Blurred vision
  • Nausea and vomiting
  • Increased thirst
  • Fatigue
  • Irritability and sudden mood swings
  • Change in appetite
  • Headache

These symptoms become commonplace when you experience spikes at night. Also, when they become continuous, you may experience different health complications. The best way to prevent such is to tackle the cause of the high blood sugar rise at night, and this is what the next section focuses on.

How to Prevent Blood Sugar Spikes at Night

Source: NutriSense

Detecting that you experience high blood sugar at night is one thing; knowing how to prevent it or manage it is another. Here, we throw light on excellent measures to avoid devastating increases in your blood sugar levels at night.

Insulin Pump 

If you have impaired glucose tolerance that gives you blood sugar spikes, an insulin pump may be an ideal measure to control your blood glucose. An insulin pump makes up for insulin sensitivity and can be used at night if you find it difficult to wake up at night. In addition, you can opt for a CGM that automatically pumps insulin to keep glucose levels in check.

Eat Healthily

Your diet plays a crucial role in helping you stay healthy and ensure complete glucose control. If you love snacks, consider opting for only those containing healthy fats.

However, it’s best if you stay away from all types of snacks and eliminate excess carbs from your diet before bedtime. Using a diet management app is one of the best ways to always eat healthily.

Physical Activity

Exercising late in the afternoon or at night can help stabilize your glucose level and reduce your chances of increased blood sugar level at night. You could incorporate moderate and high-intensity exercise depending on your strength and capability. Exercises as simple as brisk walking can go a long way in helping out.


People with diabetes are more vulnerable to the consequences of high blood sugar spikes due to the inability of their bodies to produce more insulin, which helps regulate glucose production. However, almost anyone can have blood spikes at night, and a consistent rise can lead to healthy people developing similar conditions as diabetics.

An excellent management plan is one of the best ways to counter high blood sugar rise at night. You could meet your doctor for advice and expert input on the best diabetes management plan that can help you prevent blood sugar spikes. You should also look into the preventive measures listed in this guide to help you effectively reduce high blood sugar increase before, during, and after sleep.

In addition, using a diabetes diet management app like Klinio, can also go a long way in helping you select the proper meal to take at night and throughout the whole day. It’s also an intuitive and supportive virtual caregiver that provides you with customizable no-equipment beginner workouts as well as educational content to help you understand your condition better and how best to manage it.

Written by

Braden G. Barnett, MD

Dr. Braden G. Barnett is an endocrinologist in Los Angeles, California and is affiliated with multiple hospitals in the area, including Keck Medical Center of USC and USC Norris Comprehensive Cancer Center. He received his medical degree from University of Southern California and has been in practice around 8 years. A skilled professional, Dr. Barnett holds certification from the American Board of Internal Medicine with a special focus on endocrinology, diabetes, and metabolism. He is also a recipient of several awards and honors.

Take a quiz and get your diabetes-management plan today!

Download Klinio app!

Find out what works best for you with this 60-sec expert-approved quiz and get your Klinio app.