Why Your Blood Sugar Spikes After a Bad Night’s Sleep
Blood Sugar and Your Health

Why Your Blood Sugar Spikes After a Bad Night’s Sleep

Why Your Blood Sugar Spikes After a Bad Night’s Sleep
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Published on April 29, 2026
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Everyone has a bad night’s sleep sometimes. In fact, around one-third of adults in the United States report not getting the recommended amount of shut-eye (at least seven hours a night).

 While it can leave you feeling groggy the next day, that’s not the only impact it has on your health. Inadequate sleep can also affect your ability to manage blood sugar.

“Sleep health is one of the pillars of blood sugar management,” says Russender Powell, RD, CDCES, a diabetes and lifestyle coach at Russ Powell Nutrition in Frisco, Texas. Lack of sleep quantity or quality can affect how your body handles glucose and make it harder to stick to the health habits that keep blood sugar in check. Over time, poor slumber can affect your cravings, energy, mood, and, if it persists, overall metabolic health.

Learn more about how sleep affects blood sugar and how to support healthy blood sugar levels, even if you’ve had a restless night.

What Happens to Blood Sugar After Poor Sleep

If you have type 2 diabetes, poor sleep is linked to higher levels of insulin and fasting glucose and a higher HbA1c.

 
But these effects occur even if you don’t have type 2 diabetes. “When you’re chronically sleep deprived — getting less than six hours of sleep per night — it can lead to metabolic dysfunction, which increases the risk of developing insulin resistance,” says Powell. A large cohort study found that participants who slept less than six hours a night had a 16 percent higher risk of type 2 diabetes than those who got seven to eight hours of sleep.

 Even among participants who had an otherwise healthy diet, inadequate sleep was associated with greater risk. “Your body needs that metabolic reset overnight,” she says.
Sleep plays a key role in regulating hormones that control blood sugar. Sleep loss decreases insulin, the hormone that helps move blood sugar into cells, making blood sugar spikes more likely. At the same time, levels of the stress hormone cortisol rise, which interferes with insulin function.

Why You Feel Worse Even if Numbers Appear to Be Normal

Several factors can make you feel “off” after poor sleep. Even if your A1c or fasting blood glucose is normal, your body may be hard at work producing more insulin to keep those numbers stable, Powell explains. Over time, that added strain can wear down metabolic resilience and lead to more frequent blood sugar spikes.

Those spikes can trigger a blood sugar roller coaster, where levels rise and then crash. This results in symptoms such as brain fog, low energy, and nervousness.

Poor sleep also disrupts hunger hormones, which influence the way you eat. “Sleep deprivation increases our hunger hormone, ghrelin, and decreases our fullness hormone, leptin,” says Powell. “At the same time, a sleepy brain and tired body crave quick energy, often in the form of salty, sweet, fatty, crunchy foods.” This can mean stronger cravings for ultraprocessed foods, such as candy, chips, fast food, ice cream, and soda. And research links ultraprocessed food intake to impaired glucose control and a higher risk of prediabetes over time, compounding the effects of poor sleep.

How to Support Blood Sugar When Sleep Isn’t Ideal

If you’ve had a rough night’s sleep, taking certain steps can help keep blood sugar steady, Powell says. Start with these tips:

  • Incorporate gentle movement. Light activity, such as a 10-minute walk after meals, has been shown to help regulate blood glucose levels by encouraging muscles to handle sugar more efficiently.

     When you’re sleep deprived, it’s best to skip strenuous workouts, which can further raise stress hormones. Instead, opt for low-impact activity, such as longer walks, which may help regulate stress hormones, she says.
  • Eat dinner earlier. Heavy, late meals can interfere with deep sleep. Powell recommends aiming to finish eating three to five hours before bedtime, so your body isn’t focused on digestion when you lie down.
  • Skip alcohol. While a nightcap may have a relaxing effect, alcohol disrupts sleep quality and can make blood sugar hard to manage.

     What’s more, alcohol can cause you to wake up frequently during the night, perpetuating the cycle of poor sleep and blood sugar swings.
  • Get back on track quickly. If your schedule is off one night, aim for a slightly earlier bedtime the next night to catch on sleep, but keep your wake time consistent. “The goal is to break the cycle,” says Powell. “Try to avoid two consecutive nights of poor sleep.”
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. FastStats: Sleep in Adults. Centers for Disease Control and Prevention. May 15, 2024.
  2. Darraj A. The Link Between Sleeping and Type 2 Diabetes: A Systematic Review. Cureus. November 3, 2023.
  3. Nôga DA et al. Habitual Short Sleep Duration, Diet, and Development of Type 2 Diabetes in Adults. JAMA Network Open. March 2024.
  4. New Beginnings Mini-Lesson: Sleep Health. Centers for Disease Control and Prevention. May 15, 2024.
  5. Get Off the Blood Glucose Roller Coaster. Johns Hopkins Medicine.
  6. Li Y et al. Ultra-Processed Food Intake Is Associated With Altered Glucose Homeostasis in Young Adults With a History of Overweight or Obesity: A Longitudinal Study. Nutrition & Metabolism. November 10, 2025.
  7. Hashimoto K et al. Positive Impact of a 10-Min Walk Immediately After Glucose Intake on Postprandial Glucose Levels. Nutrition & Metabolism. July 2, 2025.
  8. Gardiner C et al. The Effect of Alcohol on Subsequent Sleep in Healthy Adults: A Systematic Review and Meta-Analysis. Sleep Medicine Reviews. April 2025.
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Abhinav Singh

Abhinav Singh, MD

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Abhinav Singh, MD, is a board-certified sleep medicine specialist and the medical director of the Indiana Sleep Center. He is also an associate clinical professor at Marian Univers...

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Jessica Migala

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Jessica Migala is a freelance writer with over 15 years of experience, specializing in health, nutrition, fitness, and beauty. She has written extensively about vision care, diabet...

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