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April 22, 2021 / Alena Kharlamenko, MS, RD, CDN

Why Blood Sugar Spikes at Night & How to Prevent It

Empty bed at night with tousled pillows and light shining from the bathroom.

In a time when you’re constantly pressured to work more and generally do more things, the importance of good sleep is often overlooked. However, poor sleep can weigh you down and negatively affect your mood, memory, digestion, and physical activity. It can impact your appetite, cravings, and glucose metabolism. Lack of sleep can diminish your body’s sensitivity to insulin and elevate your blood sugar levels, even causing blood sugar spikes.

Blood sugar spikes can contribute to the development of diabetes, raising your HbA1c over time. If you have diabetes, blood sugar spikes can become dangerous, making it hard to maintain glycemic control and raising your risk of diabetic ketoacidosis and other diabetes-related complications.

Taking the appropriate steps to avoid blood sugar spikes at night can help you get better sleep, maintain better blood sugar control, and improve your quality of life.

Here, you’ll learn about blood sugar spikes and why they happen, common causes, and tips to prevent blood sugar spikes at night.

What Is a Blood Sugar Spike & How Does It Affect Me?

A blood sugar spike occurs when glucose, a simple sugar, builds up in your bloodstream and causes your blood sugar to rise quickly to a high level. Blood sugar spikes can affect people differently, depending on whether they have diabetes, prediabetes, or do not have diabetes at all.

People without diabetes

It was previously believed that blood sugar spikes didn’t necessarily happen in people without diabetes or prediabetes. However, recent research suggests otherwise.

In a 2018 study of 57 people published in the journal PLOS Biology, researchers found that blood sugar spikes occurred in people without diabetes as well as those with diabetes. They found that some people without diabetes displayed various degrees of glucose dysregulation, which they categorized into different gluctoypes. These glucotypes determined the severity of their blood sugar spikes, ranging from low, medium, and high variability.

Eating certain foods can also cause blood sugar spikes. Although your body is able to release insulin to process glucose, it’s important not to overwhelm your body or pancreas by increasing blood sugar regularly. If you find that you’re eating more added sugar lately, consider learning how to detox from sugar.

People with prediabetes

People with prediabetes are described as having impaired glucose tolerance, meaning that their blood sugar spikes after they eat foods high in carbohydrates and sugar. Prediabetes can occur when cells in the body become insulin resistant and the pancreas cannot keep up with insulin production. This causes glucose to build up in the bloodstream and elevate blood sugar levels, sometimes leading to blood sugar spikes. Over time, prediabetes can progress to type 2 diabetes if left untreated and if blood sugars continue to rise and more and more blood sugar spikes occur.

If you think you have prediabetes, it’s not too late to take action. Paying attention to symptoms of insulin resistance and prediabetes can help you prevent or delay the onset of type 2 diabetes.

People with diabetes

Blood sugar spikes can be dangerous for people with diabetes. If left untreated, blood sugar spikes can lead to a serious complication called diabetic ketoacidosis (DKA). When cells are insulin resistant, blood sugar stays in the bloodstream and cells become starved for energy.

Eventually, cells start breaking down fat for energy, producing a byproduct called ketones. If too many ketones build up in the body, they cannot be excreted in urine and can lead to diabetic coma or death without treatment. Sometimes DKA happens when people are newly diagnosed with diabetes because high blood sugars go unchecked and untreated for a long period of time.

Frequent blood sugars spikes and elevated blood sugars in people with diabetes can lead to diabetes-related complications like chronic kidney disease, heart disease, vision problems, and nerve damage.

Causes of Blood Sugar Spikes

You may think that blood sugar is only affected by the food you eat. However, there are a number of factors that can cause blood sugar spikes, including:

Why Do Blood Sugar Spikes Happen at Night?

There are a few explanations behind why your blood sugar spikes at night. If you’re on diabetes medication, you may not be taking the right dose or at the right time. The food you eat at night also plays a role. Eating a high-carb late-night meal or snack can instigate a blood sugar spike at night. Additionally, eating a high-carb dinner that is also high in fat can delay blood sugar absorption, causing blood sugars to rise several hours after eating.

If it’s not one of these reasons, your night-time blood sugar spikes could be due to the dawn phenomenon (or dawn effect) or the Somogyi effect.

The dawn phenomenon usually occurs between 3 a.m. and 8 a.m. It is caused by your body releasing sugar into your bloodstream so that you have enough energy to start the next day. These hormones raise your blood sugar to give you energy. Simultaneously, a hormone called cortisol is released to prepare your body to wake up, but it can reduce your body’s sensitivity to insulin. This causes excess blood sugars to remain in the blood rather than being used for energy.

The Somogyi effect, also known as rebound hyperglycemia, happens when your blood sugars drop overnight and your body releases hormones that prompt your blood sugars to rise. Sometimes this is an overcorrection, and can actually lead to hyperglycemia and a spike in your blood sugar.

If you suspect blood sugar spikes at night, pay attention to how you feel overnight or in the morning. You may wake up with some of these symptoms:

Can High Blood Sugar Keep You Up at Night?

High blood sugar at night can turn into a vicious cycle. On one hand, high blood sugar can affect your sleep by increasing the need and frequency that you have to urinate overnight as your body tries to get rid of the excess sugar. The frequent interruptions in sleep decrease the quantity and quality of your sleep. In fact, research suggests that up to one-third of people with diabetes have associated sleep disorders.

On the other hand, poor sleep can actually lead to insulin resistance, high blood sugar, increased risk of type 2 diabetes, or poor glycemic control and increased risk of diabetes-related complications if you have diabetes. It has also been shown to decrease quality of life in those with diabetes.

There are ways to lower blood sugar naturally if it gets high. If blood sugar spikes happen infrequently or are not severe, these strategies may help, however it is recommended to get help from a medical professional if they persist.

Tips for Preventing Blood Sugar Spikes at Night

If you’re worried about high blood sugar overnight, we have your back. There are certain actions you can take that may help prevent blood sugar spikes at night.

Tip #1: Exercise the right amount

When it comes to exercise and blood sugars, there’s a sort of Goldilocks effect: too much and too high intensity exercise and your blood sugars will rise; too little exercise and your blood sugars will also rise.

So, what’s the right amount?

Research shows that moderate or low-intensity exercise may result in a reduction of blood sugar levels at night. In a 2018 study, researchers found that a 20-minute low-intensity treadmill walking workout after dinner reduced postprandial blood sugars (blood sugars after a meal) in those with type 2 diabetes. However, it is not recommended to exercise if your blood sugar levels are too high (usually 250 mg/dL or higher) as it could potentially lead to diabetic ketoacidosis.

Tip #2: Stay hydrated

Staying properly hydrated is a very important way to improve gut health and even improve overall health and wellness, but did you know that your hydration status also has an impact on your blood sugar control? In a 2011 study published in Diabetes Care, researchers found that those who reported a low water intake of less than 1 liter per day had a higher risk of high blood sugar.

Your body releases a hormone called vasopressin when you’re dehydrated. Elevated vasopressin has been shown to affect blood sugar status because it causes your liver to release more sugar into your bloodstream. It also has an antidiuretic effect and signals for your kidneys to retain water, which stops excess sugar from getting flushed out of your body.

To stay hydrated and avoid blood sugar spikes, aim for water and other unsweetened beverages, like sparkling water or fruit-infused water.

Tip #3: Stress less

Having a stress management plan in place can help prevent blood sugar spikes at night. Stress can cause your body to release “stress” hormones like cortisol, which reduces your body’s sensitivity to insulin. This in turn triggers a blood sugar spike.

Avoiding stress or learning how to manage stress can be a key to prevention. Whether it’s at-home yoga flow, meditation, journaling, or calling a loved one, find a stress-management strategy that works for you. Research supports this—a 2014 study found that yoga practice was linked with a reduction in stress and postprandial blood sugar levels.

Tip #4: Evaluate your diet

Unsurprisingly, your diet can impact your blood sugar levels at night. Even the timing of your meals can have an effect. A 2018 study published in Nutrients found that postprandial blood sugar levels were more elevated after evening meals compared to morning meals. This could be because insulin response is higher in the morning than at night, or because of the effect of the circadian rhythm of hormones involved in glucose metabolism.

The foods you eat also impact blood sugar spikes. A carb-rich meal in the absence of adequate protein, fat, or fiber will more likely result in a blood sugar spike than a balanced meal with plenty of fiber, healthy fats, and protein. A 2018 study’s findings suggested that a low-carb, high-protein diet combined with omega-3 fatty acids promoted better glycemic control and could help minimize postprandial blood sugar spikes.

By making adjustments to your diet, you may be able to avoid or delay the development of type 2 diabetes. A prediabetes diet plan can be the starting point you need to make healthy changes to the way you eat.

Tip #5: Get adequate sleep

Poor sleep can negatively impact your blood sugars at night. As we mentioned earlier, a lack of sleep can have a detrimental effect on your blood sugars. It can affect your appetite, cravings, and metabolism, sometimes causing you to eat more or crave more carb-rich foods. It can also cause your body to release hormones that can increase insulin resistance, blood sugar levels, weight, risk of type 2 diabetes, and blood sugar spikes at night.

To avoid these effects, aim for seven to nine hours of sleep each night.

Tip #6: Discuss blood sugar spikes with your healthcare provider

Many people do not realize they may have prediabetes or diabetes. In fact, the Centers for Disease Control and Prevention (CDC) estimate that more 84% of people don’t know they have prediabetes. However, if you’re looking for ways to measure HbA1c, you can take a simple blood test to have your blood sugar levels evaluated to determine if you have prediabetes or diabetes.

Talk to your doctor about managing blood sugar spikes. If you have diabetes, your doctor may suggest making changes to medication levels and timing. These changes could lessen the occurrence of blood sugar spikes at night.

The Takeaway

Poor sleep and high nighttime blood sugars are not a cycle you want to fall into. Managing blood sugar spikes at night can help reduce your risk of type 2 diabetes, or improve blood sugar control and prevent the onset of diabetes-related complications if you do have diabetes. Most of all, it can help improve your quality of life.

You can take action to prevent blood sugar spikes at night by making sustainable changes to the way you eat, drink, sleep, exercise, and manage your stress. PlateJoy’s meal planning services can help you achieve a healthy lifestyle and manage your health, from taking the stress out of healthy meal planning to providing you with low-carb keto meal plans.

Alena Kharlamenko, MS, RD, CDN
Registered Dietitian and Nutrition Consultant @ Alena Menko Nutrition

Alena Kharlamenko is the founder of Alena Menko Nutrition, a food and nutrition blog where she publishes healthful, plant-forward recipes and makes nutrition approachable with easily digestible information. She’s also passionate about gut health and is a Monash FODMAP-Trained Dietitian. When she's not cooking up a storm in the kitchen or behind her computer, she can be found exploring the vast culinary scene of NYC, traveling around the world, or hiking and spending time in nature. You can find Alena on Instagram @thebalancedbite or on Facebook @AlenaMenkoNutrition.

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