What Should Blood Sugar Be at Bedtime?

What your blood sugar should be at bedtime depends on a few factors. Find out what they are, what may cause your glucose levels to fluctuate at night, and more.

A woman sleeping in bed with an eye mask over her eyes

Tracking and checking blood sugar isn’t just for people with diabetes anymore. There’s a wealth of health information you can learn about your body from continuous glucose monitoring, and you can use this knowledge to help achieve your wellness goals. 

As you begin monitoring your glucose around the clock, you’ll learn how certain foods, activities, and lifestyle choices affect your blood sugar. Once you get the hang of targeting optimal glucose ranges before and after meals, you might wonder what your ideal blood sugar should be before bed. 

Target Blood Sugar Range at Bedtime

People without diabetes should aim for a blood sugar range of 72–90 mg/dL or 4.0–5.0 mmol/L at bedtime for optimal health. 

<p class="pro-tip"><strong>Learn more about </strong><a href="/blog/blood-sugar-bedtime">normal blood sugar levels for people without diabetes</a></p>

Non-pregnant adults with diabetes often target a blood sugar range of 80–130 mg/dL or 4.4–7.2 mmol/L. However, blood glucose targets should be individualized for those with diabetes. 

Let’s take a deep dive into understanding blood sugar at bedtime and how this may impact your overall health goals. 

What Causes High Blood Sugar at Night?

Hyperglycemia, the technical term for elevated blood sugar, occurs when glucose levels are greater than 180 mg/dL.

For people without diabetes, average blood sugar ranges are:

  • Fasting glucose: <100 mg/dL or 5.6 mmol/L
  • Glucose range before eating: 80–130 mg/dL or 4.4–7.2 mmol/L
  • Glucose range 1–2 hours after eating: <140 mg/dL or 7.8 mmol/L

For people with diabetes, average blood sugar ranges are: 

  • Fasting glucose: 126 mg/dL (7.0 mmol/L) or higher
  • Glucose range before eating: 80–130 mg/dL (4.4–7.2 mmol/L)
  • Glucose range 1–2 hours after eating: <180 mg/dL (10.0 mmol/L)

If your blood sugar readings at bedtime are higher than your goal, consider whether one or more of the following factors could be the cause.

Late Evening Meals or Snacks

Glucose readings may fluctuate depending on the amount of time that has passed since your last meal. If you experience high blood sugar at night, one of the first things to consider is how long it’s been since you last ate. 

A small study conducted on healthy men and women observed participants wearing continuous glucose monitors for almost three days and provided dinner to one group at 6 p.m. and the other at 9 p.m. Only data from the mornings of days 2 and 3 were used for analysis, and results showed a significant decrease in postprandial respiratory quotient after breakfast on day 3 in the early dinner group. Researchers concluded that eating an earlier dinner had a positive impact on blood glucose fluctuation<sup>1</sup> and metabolism. 

Evening Meals with Fat and Carbohydrates

Meals full of both fat and carbohydrates may require a longer time for digestion, resulting in higher glucose readings several hours after eating. 

One study with young, healthy participants showed that eating a late dinner composed of 50% carbs, 35% fat, and 35% of total daily calories caused a prolonged glucose intolerance and reduced fatty acid oxidation<sup>2</sup> during sleep—particularly in those who hit the hay earlier—and an increase in cortisol. Researchers hypothesized that these same metabolic reactions could contribute to obesity if repeated consistently. 

Medication

Steroids such as hydrocortisone, dexamethasone, and prednisone are often used to control inflammation, manage asthma flare-ups, or suppress autoimmune reactions. However, these medications also can cause a dramatic increase in blood sugar. 

Even people without diabetes may experience steep spikes in blood sugar<sup>3</sup> while taking steroids, and long-term treatment may increase a person’s chance of developing diabetes. 

However, inhaled steroids for asthma and topical formulations such as creams and ointments won’t affect your blood sugar. 

Some medications used for depression, anxiety, ADHD, birth control, high cholesterol, or high blood pressure also can increase blood glucose levels. 

Alcohol

Alcoholic beverages contain carbohydrates and are often high in calories, which can wreak havoc on your blood sugar control. Alcohol also stimulates your appetite<sup>4</sup>, which can prompt you to eat more, making it more difficult to stay within the ideal glucose range. 

What’s more, the body prioritizes alcohol metabolism first, so any food you might eat with that glass of wine, beer, or spirit gets processed after the alcohol. This can lead to more prolonged or delayed glucose responses to the food you eat while drinking. 

Stress

Believe it or not, stress can be a huge factor that affects your blood sugar. During times of emotional hardship, your body releases stress hormones, such as cortisol, which prompts an increase in glucose even if you haven’t eaten. 

Illness

Much like emotional stress, sickness can impose physical stress on your body. Whether it’s a cold, the flu, or something more serious, your body responds to illness by releasing glucose<sup>5</sup>. When you’re sick, you may be surprised to have high blood sugar even if you haven’t had normal food intake.

Sugary Drinks

It may be obvious that sweet drinks like soda and juice will spike your blood sugar, but consuming sugary beverages can be a hard habit to break. Many people opt for artificially sweetened beverages in place of the real deal. 

However, a review of current research suggests that artificially-sweetened drinks may affect glycemic control<sup>6</sup> (albeit indirectly). Artificial sweeteners may also alter your gut microbiota; one study examined in the review demonstrated that artificial sweeteners induce glucose intolerance in mice and human subsets. More research is needed to fully understand the role of artificial sweeteners in managing blood sugar.

Good old-fashioned water is always the best choice for hydration and health. 

Dehydration

With less water in your bloodstream, glucose becomes more concentrated. Drinking adequate amounts of water is crucial for optimal blood sugar control.

Hormonal Changes

We discussed previously that stress hormones affect blood sugar, but hormonal changes that occur in the premenstrual phase of a woman’s monthly cycle may play a role<sup>7</sup>, too. More research is needed to fully understand this phenomenon. 

Inadequate Sleep

It is well-documented that poor sleep has wide-ranging effects on the way our bodies process glucose. Sleep problems are linked not only to high blood sugar<sup>8</sup>, but also insulin resistance, type 2 diabetes, metabolic syndrome, and obesity. 

What Is the “Dawn Effect”?

The dawn effect, sometimes called the dawn phenomenon, is when your body naturally releases a surge of glucose into your bloodstream in the early hours of the morning. It usually takes place sometime between 3 a.m. and 8 a.m.

  • People without diabetes may see this increase in glucose, but the body will release insulin to bring blood sugar back to normal.  
  • People with diabetes may struggle to control their blood sugar in the morning since their bodies have difficulty producing or using insulin to manage the glucose surge. 

Symptoms of High Blood Sugar

People with diabetes may have some of these symptoms<sup>9</sup> when their blood sugar is high: 

  • increased thirst
  • frequent urination
  • fatigue
  • blurred vision
  • headache 

However, if you don’t have diabetes, you likely will not experience symptoms related to high blood sugar. Why? Because your body manages glucose appropriately. You won’t have the same symptoms as a person with diabetes who struggles to manage the excess glucose.

What to do if Your Blood Sugar Is High at Bedtime

If you’re using the Signos app, you’ll receive an alert to let you know when your glucose is out of range. If your glucose is high, consider exercising for at least 10 minutes to lower your levels. 

Here are a few ideas:

  • Try a yoga class from an app or a free version on YouTube 
  • Take a brisk walk outside
  • Walk up and down stairs
  • Ride a stationary bike
  • Jump rope
  • Perform bodyweight exercises such as planks, squats, push-ups, and sit-ups. 

What Causes Low Blood Sugar at Night?

Hypoglycemia, or low blood sugar, is defined as a glucose reading less than 70 mg/dL. 

People with diabetes must manage their blood sugar and their medication regimen carefully to avoid hypoglycemia. 

However, if you do not have diabetes, it is unlikely you’ll experience sustained hypoglycemia resulting in troublesome symptoms. 

Some people experience what is known as nocturnal hypoglycemia when glucose dips during sleep. This happens to people with diabetes if they eat too little in the evening or give themselves too much insulin. In addition, people with diabetes may experience low blood sugar if they exercise too much without supplementing their food intake. 

Here are some more variables that can contribute to low blood sugar:

  • Alcohol: Although alcohol can cause a spike in blood sugar, an excess can also cause glucose to plummet. 
  • Medications: For people with diabetes, insulin and other diabetes medications are a frequent cause of low blood sugar. 

However, a review published in The Journal of Clinical Endocrinology & Metabolism showed that other medications may contribute to low blood sugar<sup>10</sup> as well, such as:

  • Antibiotics, such as ciprofloxacin, levofloxacin, moxifloxacin
  • Quinidine, a medication used for malaria treatment
  • Pentamidine, used for severe infections

That said, researchers noted that very low-quality evidence backs up the association between low blood sugar and the use of non-diabetic drugs.

While popular heart and blood pressure medications such as beta-blockers and ACE-inhibitors have been linked with episodes of low blood sugar<sup>11</sup> as well, more research is needed to determine whether these medications cause low blood sugar. 

If you don’t have diabetes but have ongoing trouble with low blood sugar, you should talk to your doctor. Serious problems such as liver disease, autoimmune disease, kidney problems, and certain tumors can cause low blood sugar, so seek medical help to determine the underlying cause. 

Symptoms of Low Blood Sugar

Here are some of the signs associated with low blood sugar:

  • shaking
  • sweating
  • fast or irregular heartbeat
  • hunger
  • anxiety or irritation
  • dizziness
  • loss of balance
  • confusion
  • tingling of extremities
  • slurred speech
  • nausea or vomiting

What to do if Your Blood Sugar Is Low at Bedtime

If your blood sugar is below your target range at bedtime, try eating a small, healthy snack such as:

  • One serving of a medium or low glycemic fruit. Consider options such as apples, strawberries, oranges, bananas, pears or dates. Avoid watermelon, pineapple and other high-glycemic fruits or choose a smaller serving. 
  • several whole-grain crackers
  • a cup of milk
  • plain Greek yogurt
  • a hardboiled egg
  • a handful of nuts
  • veggies with hummus

More quick tips for stabilizing blood sugar overnight

If your blood sugar is bouncing all over the place at night, try these simple changes to your evening routine. 

  • Don’t skip dinner. 
  • Eat a balanced evening meal with plenty of veggies and lean protein.
  • Eat dinner at least three hours before bedtime. 
  • Take your blood sugar level before bed.
  • Eat a healthy snack if your sugar is low at night.
  • Give yourself 10 minutes of exercise if your sugar is high before bed. 
  • If you experience low blood sugar overnight, don’t engage in intense exercise right before bed. 
  • Be sure to get at least 7 hours of sleep each night. 
  • Minimize stress.
  • Practice meditation before bedtime.
  • Drink plenty of water throughout the day.
  • Be sure to engage in a regular schedule of exercise.
  • Avoid drinking alcohol at night.

As you implement these tips for managing your glucose, keep in mind that it’s a process. Continuous glucose monitoring will allow you to get to know your body better with time, and you’ll begin to understand exactly what your body needs. 

And remember—strive for progress, not perfection. 


More Signos Articles About Glucose & Blood Sugar

Glucose & Blood Sugar FAQs

Lowering & Stabilizing Your Blood Sugar

Low-Glycemic Diet


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About the Author

Courtney Schmidt Headshot
Courtney Schmidt, PharmD, is an award-winning freelance health writer whose work has appeared on a variety of well-known health and wellness publications.
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Please note: The Signos team is committed to sharing insightful and actionable health articles that are backed by scientific research, supported by expert reviews, and vetted by experienced health editors. The Signos blog is not intended to diagnose, treat, cure or prevent any disease. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider. Read more about our editorial process and content philosophy here.

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