Woke up to high blood sugar? Here’s what might be happening

If you live with diabetes and track your blood sugar regularly, you might’ve noticed something odd: your fasting sugar levels in the morning are often higher than they were the night before, even if you skipped a bedtime snack. This phenomenon is known as the Dawn Phenomenon, and it’s more common than you might think.

What is the Dawn Phenomenon?
Dr Tarjani Vyas, Consultant Diabetologist, Ahmedabad, explains, “The dawn phenomenon is a natural rise in blood sugar levels that occurs in the early morning (usually between 4–6 AM). This happens because the body releases hormones like cortisol and growth hormone to prepare us for waking up. These hormones reduce insulin sensitivity, causing blood sugar to rise, especially in people with diabetes.”

The role of hormones in morning glucose spikes
This spike is driven by hormones like cortisol, growth hormone, glucagon, and adrenaline. These are called counter-regulatory hormones because they work against insulin, causing the liver to release more glucose into the bloodstream.

According to Dr Tarjani, “Hormones like cortisol, adrenaline, and growth hormone are released during the early hours of sleep. In people with Type 2 diabetes, the body either doesn’t make enough insulin or doesn’t respond to it well. So when these hormones raise blood sugar, the body can’t bring it down effectively.”
Is it the Dawn Phenomenon or the Somogyi Effect?
Many people confuse the Dawn Phenomenon with the Somogyi Effect, which is a rebound high blood sugar following an overnight low (hypoglycemia). The Somogyi Effect is typically a result of excess insulin or missed meals before bed, which causes a dip in sugar that the body "corrects" by overshooting into high territory.

The key difference, as per the Diabetician, is as follows:

• Dawn phenomenon: gradual rise without night-time lows.
• Somogyi effect: low sugar around 2–3 AM, followed by a rebound high.

A continuous glucose monitor (CGM) or manual testing at 2 a.m. and 3 a.m. can help pinpoint whether the sugar is gradually rising (Dawn Phenomenon) or dipping first and then rising (Somogyi).

Managing high morning sugar levels
Fortunately, there are several ways to mitigate the impact of the Dawn Phenomenon through adjustments to diet, exercise, or medication.

To maintain better overnight blood sugar control, it’s essential to be mindful of your evening routine. Dr. Tarjani advises, “Opt for complex carbohydrates paired with protein and fibre at dinner, and avoid sugary snacks late at night, as they can lead to glucose spikes while you sleep.” She also emphasises that regular physical activity can enhance insulin sensitivity, making it easier for the body to manage blood sugar levels. In some cases, adjusting the timing or dosage of evening diabetes medications or insulin may be necessary, but such changes should always be made under medical supervision.

In short:
● Choose complex carbs with protein and fibre for your evening meals.
● Avoid late-night sugary snacks to prevent overnight blood sugar spikes.
● Exercise regularly to improve insulin sensitivity.
● Adjusting the timing or dose of evening diabetes medications or insulin may help
However, it is always advisable to consult your doctor before making any changes to your treatment plan.

The role of monitoring in management
Dr Tarjani believes monitoring sugar levels consistently, especially in the early hours, is key to identifying patterns. She adds, “Regular monitoring helps track patterns, which is very useful. CGMs offer detailed overnight data and track 24-hour blood glucose patterns, while glucometers can catch early morning highs. This helps tailor treatment, prevent complications, and gives both patients and doctors better control over diabetes.”
In a nutshell
Understanding that the Dawn Phenomenon is a natural physiological process, not a result of dietary missteps, can be reassuring. With smart monitoring, informed choices, and medical guidance, managing those pesky morning spikes is entirely possible.

Doctor consulted:

<p><em></em><em>Dr Tarjani Vyas, Consultant Diabetologist, Ahmedabad</em><br></p>

Sources:
https://www.mayoclinic.org/diseases-conditions/diabetes/expert-answers/dawn-effect/faq-20057 937
https://my.clevelandclinic.org/health/diseases/24553-dawn-phenomenon


Disclaimer: The views and opinions expressed in the story are independent professional judgments of the doctors/experts, and TIL does not take any responsibility for the accuracy of their views. This should not be considered a substitute for medical advice. Please consult your treating physician for more details. This article has been produced on behalf of Roche by Times Internet’s Spotlight team.