What causes glucose spikes at night?

Why glucose spikes at night: The dawn phenomenon | Stelo by Dexcom
All articles
Sleep
Why glucose spikes at night:
The dawn phenomenon
Published
:
May 28, 2025
Updated
:
Aug. 20, 2025
3 min read
Table of contents
Dawn phenomenon: Your body’s natural wake-up call
Spot the pattern, take the next step
Data that brings clarity
The content in this article should not be taken as medical advice. Please consult with your healthcare provider regarding your individual health needs.
Have you ever checked your glucose in the morning and thought, “Wait, why is it high when I didn’t even eat anything?” You’re not alone. Overnight glucose spikes can be confusing and frustrating, especially when you’re doing your best to manage your health. The truth is, your body has a lot going on behind the scenes while you sleep. One particular thing that could cause those early morning highs: the dawn phenomenon.
Dawn phenomenon: Your body’s natural wake-up call
Unlike other causes of
glucose spikes , the dawn phenomenon doesn’t start with a drop in glucose levels—it starts with your body’s natural rhythm. In the early hours of the morning (3–5 a.m.), your body releases hormones like cortisol .
But here’s the thing: those hormones can also make your body more resistant to insulin. That means your glucose levels might climb, even if you didn’t eat anything or experience a low beforehand.
Signs of the dawn phenomenon:
Your glucose is steady throughout the night, then rises starting in the early morning, often before you’re even out of bed.
Spot the pattern, take the next step
Knowing whether you’re experiencing the dawn phenomenon can help you take action—and that starts with having visibility into your overnight glucose trends.
That’s where a glucose biosensor like Stelo can be helpful. Tracking your glucose through the night (and the rest of the day too) gives you the full picture. With more context on how your sleep affects your glucose, it’s easier to connect the dots and take actionable steps to address any issues.
If you think you may be experiencing the dawn phenomenon, it’s worth flagging to your healthcare team, as they may have suggestions to prevent glucose spikes. Lifestyle tweaks like improving sleep, reducing stress , staying active, and making supportive food choices can help your body respond more smoothly in the early hours.
Data that brings clarity
Overnight glucose shifts can be tricky, but they’re also patterns you can learn from. Whether it’s a natural hormone surge before you wake up, the key is spotting what’s happening consistently.
Getting a full view of your glucose overnight, you can start to see those trends for what they are. It’s not about guessing or assuming—it’s about having the info you need to make smart decisions and bringing that context to your next check-in with your care team. No overthinking. No mystery. Just a clearer picture of how your body works, so you can respond with confidence.
Stay in the loop
Sign up to receive the latest from Stelo.
Subscribe now
Curated & reviewed by: Jami Klein,
RN, BSN, CDCES
Jami Klein is a registered nurse and certified diabetes care and education specialist with extensive experience in both clinical settings and diabetes industry.
Learn more
Written by: Stelo Team
Related articles
View all
About
Our heritage Info session: Meet Stelo Stelo by Dexcom App Partners
Support
Help center Account Check order status FSA/HSA
Information
Consumer Health Data Privacy Policy
US State Privacy Rights Trust Center
Your Privacy Choices
Cookie Settings Stelo for Providers
by Dexcom
Terms of Use Privacy Policy Safety Information Security at Dexcom
Dexcom, Dexcom Clarity, Dexcom Follow, Dexcom One, Dexcom Share, Stelo, and any related logos and design marks are either registered trademarks or trademarks of Dexcom, Inc. in the United States and/or other countries. ©2026 Dexcom, Inc. All rights reserved.
MAT-3641
•
MAT-8694
©
2026 Stelo, Inc. All rights reserved.

Text scraped from the landing page for research purposes. © respective owners. This text is sourced from the advertiser's public landing page; for removal, contact dmca@luba.media.