The Link Between Sleeping Early and Blood Sugar Control: What You Need to Know
24th Mar 2025
How Sleep Affects Blood Sugar: Impact, Spikes & Nighttime Tips
Sleep is often overlooked as a cornerstone of good health, but its impact on our metabolic well-being, particularly blood sugar regulation, is huge.
While most people focus on diet and exercise, the timing and quality of your sleep can have a significant impact on how your body manages blood sugar levels.
Research shows that even a single night of poor sleep can reduce insulin sensitivity by up to 25 per cent, leading to higher blood sugar levels and long-term health risks.
But it’s not just about how much you sleep — when you sleep matters too.
Know what you’re looking for? Head there now:
- How Does Sleep Affect Blood Sugar Regulation?
- Why Does Sleep Timing Matter for Blood Sugar?
- The Role of Sleep Stages in Blood Sugar Regulation
- FAQs
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How Does Sleep Affect Blood Sugar Regulation?
Sleep plays a huge role in maintaining healthy blood sugar levels. During sleep, your body goes through essential processes that help regulate hormones like insulin and cortisol, both of which influence blood sugar.
- Insulin Sensitivity: Sleep deprivation reduces your body’s ability to respond to insulin, the hormone that helps cells absorb glucose from the bloodstream. This leads to higher blood sugar levels and increased insulin resistance, a precursor to type 2 diabetes.
- Hormonal Imbalance: Lack of sleep disrupts the balance of hunger hormones, raising ghrelin (which makes you hungry) and lowering leptin (which makes you feel full). This often leads to cravings for sugary, processed foods, further spiking blood sugar levels.
- Circadian Rhythm: Your body’s internal clock, or circadian rhythm, influences metabolic processes. Disrupting this rhythm — by staying up late or having irregular sleep patterns — can damage glucose tolerance and insulin sensitivity.
A study using continuous glucose monitors (CGMs) found that those who slept less than 8 hours or went to bed after midnight had larger blood sugar spikes and more variability in glucose levels. The worst combination? A late bedtime paired with not enough sleep.
Why Does Sleep Timing Matter for Blood Sugar?
Your body runs on a 24-hour internal clock known as the circadian rhythm. This rhythm regulates everything from hormone production to metabolism and it thrives on consistency. When you go to bed late or have irregular sleep patterns, it disrupts this rhythm, leading to problems like insulin resistance and poor blood sugar control.
Research shows that people who go to bed early (before midnight) tend to have more stable blood sugar levels compared to night owls. A study found that participants who went to bed after midnight had higher blood sugar variability and poorer glucose control than those who slept earlier. This is because your body is more insulin-sensitive earlier in the day and less so at night. When you stay up late, you’re essentially asking your body to process glucose at a time when it’s least equipped to do so.
What’s more, another study using continuous glucose monitors (CGMs) found that people who went to bed late had larger and more frequent blood sugar spikes compared to early sleepers.
The Role of Sleep Stages in Blood Sugar Regulation
Not all sleep is created equal. Your sleep cycle consists of different stages, including light sleep, deep sleep and REM (rapid eye movement) sleep. Each stage plays a unique role in maintaining metabolic health:
- Deep Sleep: This stage is important for physical restoration and hormone regulation. During deep sleep, your body releases growth hormone, which helps regulate glucose metabolism. Disruptions in deep sleep can impair insulin sensitivity and lead to higher blood sugar levels.
- REM Sleep: This stage is associated with brain activity and dreaming. While its direct impact on blood sugar is less clear, poor REM sleep has been linked to increased stress and cortisol levels, which can indirectly affect glucose control.
Studies show that people who experience fragmented sleep — frequent awakenings or insufficient deep sleep — are more likely to have poor blood sugar control.
Let’s go over some frequently asked questions about sleep and blood sugar so you’re aware of the blood sugar and sleep link, as well as any potential blood sugar and sleep problems.
FAQs
Does Lack of Sleep Affect Blood Sugar?
Even one night of poor sleep can increase insulin resistance, leading to higher blood sugar levels. Chronic sleep deprivation is even more damaging, contributing to long-term issues like:
- Elevated fasting glucose levels
- Increased HbA1c (a marker of long-term blood sugar control)
- Higher risk of type 2 diabetes
Taking Ashwagandha may also help lower blood sugar naturally, which is also a herb commonly used for its relaxation benefits, which may help your sleep.
Does Waking Up Early Affect Blood Sugar?
Waking up early can positively impact blood sugar control, but only if you’re getting enough sleep overall.
Research shows that early risers tend to have more stable blood sugar levels, likely because their sleep patterns align better with their circadian rhythm. Just know that going to bed early doesn’t compensate for not getting enough sleep. For example, someone who goes to bed at 10pm but only sleeps 5 hours will still experience poor blood sugar control compared to someone who sleeps 8 hours, regardless of bedtime.
What Is the 3am Syndrome with Diabetes?
The 3am syndrome refers to a phenomenon where blood sugar levels drop dangerously low during the night, often around 3am. This is particularly concerning for people with diabetes, as it can lead to nocturnal hypoglycemia. Symptoms can include:
- Nightmares
- Sweating
- Confusion upon waking
If you have diabetes, it’s important to monitor your blood sugar levels before bed and consider a bedtime snack if needed.
What Drink at Bedtime Lowers Blood Sugar?
Certain drinks can help stabilise blood sugar levels before bed:
- Chamomile Tea: Known for its calming properties, chamomile tea may also help lower blood sugar levels.
- Apple Cider Vinegar Drink: Mix 1–2 tablespoons of apple cider vinegar with water. Studies suggest it can improve insulin sensitivity and reduce morning blood sugar spikes.
- Warm Milk: A small glass of unsweetened almond or cow’s milk provides protein and can help prevent nighttime hypoglycemia.
Avoid sugary drinks or caffeine, as they can disrupt sleep and spike blood sugar.
Further Reading: Supplements for People with Diabetes
Will My Body Wake Me Up If My Blood Sugar Is Low?
In some cases, yes. Symptoms of low blood sugar (hypoglycemia) during sleep, such as sweating, nightmares or a racing heart, can wake you up, but not everyone experiences these symptoms, which is why monitoring blood sugar levels before bed is incredibly important for people with diabetes.
What to Know About Blood Sugar Spikes During Sleep
It’s normal for blood sugar levels to rise slightly during sleep due to the body’s natural circadian rhythm. Excessive spikes, though, can be a sign of poor blood sugar control. Factors that contribute to nighttime spikes include:
- Eating heavy or sugary meals close to bedtime
- Not enough insulin production or sensitivity
- Stress or poor sleep quality
Is It Safe to Sleep with High Blood Sugar?
Sleeping with consistently high blood sugar levels is dangerous and can lead to complications like diabetic ketoacidosis (DKA) in people with type 1 diabetes. For those with type 2 diabetes, chronic high blood sugar during sleep increases the risk of cardiovascular disease and nerve damage.
How to Prevent Blood Sugar Spikes at Night
Here are some practical tips to keep your blood sugar stable while you sleep:
- Avoid Late-Night Snacks: Finish eating at least 3 hours before bedtime.
- Choose Low-Glycemic Foods: Choose protein-rich snacks like nuts or Greek yogurt if you need a bedtime snack.
- Stay Active: Regular exercise improves insulin sensitivity and helps regulate blood sugar.
- Monitor Blood Sugar: Use a CGM or test your blood sugar before bed and upon waking.
- Focus On Sleep Hygiene: Try to get 7–9 hours of quality sleep each night.
Consider taking Trans-Resveratrol to prevent high blood sugar, which the NCCIH is funding research on.
Can You Die from Low Blood Sugar in Your Sleep?
While rare, severe hypoglycemia during sleep can be life-threatening, especially for people with diabetes. This is why it’s so important to monitor blood sugar levels and get medical advice if you experience frequent nighttime lows.
Why Blood Sugar Rises in the Morning
If you’ve ever noticed higher blood sugar levels in the morning, you’re not alone. This is known as the dawn phenomenon, a natural rise in blood sugar that occurs between 4am and 8am. It happens for a couple of reasons:
- Hormonal Changes: In the early morning hours, your body releases hormones like cortisol and growth hormone to prepare for waking up. These hormones can temporarily increase blood sugar levels.
- Insulin Resistance: For people with diabetes or prediabetes, the body may not produce enough insulin to counteract this rise, leading to a higher morning blood sugar.
While the dawn phenomenon is normal, consistently high morning blood sugar levels may indicate poor glucose control and should be discussed with a healthcare provider.
End Note
Sleep and blood sugar are deeply interconnected. Poor sleep habits — whether it’s not enough sleep, a late bedtime or disrupted sleep — can wreak havoc on your blood sugar levels and increase your risk of metabolic disorders like type 2 diabetes. On the flip side, focusing on good sleep hygiene, going to bed early and getting enough rest can significantly improve blood sugar control and your overall health.
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