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Guide to Dawn Phenomenon

Adam Bataineh, MD

Longevity MD


🎶 ” It’s a new dawn. It’s a new day. It’s a new life. For me. And I’m feeling good…” 🎶

And then you get the fright of your life when blood sugars are >5.6 mmol/l 😱

Has this ever happened you? You wake up, feel amazing but your morning fasting blood sugars, are at their highest?  I’m sure you’re wondering, how could this be? Surely after a whole night of fasting, blood sugars should be at their lowest?! Don’t worry, you haven’t demolished a donut or eaten a million spiders in your sleep.

This is a completely normal physiological response as a result of our circadian rhythm. It is know as the dawn phenomenon and its purpose it to kick the body into wake up mode.

For diabetes, blood sugar control is disrupted, so the dawn effect is more pronounced than normal. Please understand that as you improve your insulin sensitivity, so too will the dawn phenomenon. Let’s have a closer look at what’s going on, and how you can improve your morning, fasting blood sugars.

So where does this sugar come from, if we haven’t eaten?

The circadian rhythm is an internal clock, which regulates our sleep-wake and feeding schedule. This natural, 24 hours cycle is orchestrated by sunlight, however, each of us has a unique, endogenous rhythm. Our personal clock directs the rise and fall of hormones, making us feel awake, tired and hungry.

This is a reason why avoiding screen time before bed is a good idea — blue light (same as sunlight) disrupts the cycle, tricking the body into thinking its daylight, and thus leading to poor sleep and nocturnal hunger.

Roughly between 4–8AM, a cocktail of hormones rise with the sun that gently lull us into a state of consciousness to prepare us for the day ahead. These hormones are called adrenalin, cortisol, glucagon and growth hormone, which are counter regulatory to insulin, i.e. they increase circulating glucose levels. They do this by two processes — glycogenolysis and gluconeogenesis.

Glycogenolysis breaks down stored glucose (glycogen) in muscle and liver tissue, and releases it into the blood stream.
Gluconeogenesis synthesises glucose from non-carbohydrate precursors, like amino acids.

So why doesn’t everyone experience morning, sugar highs?

In response to blood sugars rising, the body produces insulin. Insulin directs glucose into the cell, and out of the blood stream, which returns the body to a state of homeostasis.

For ‘normal’, non-diabetics, this process is pretty controlled and streamline. The body can produce enough insulin, and cells respond to insulin signals, allowing glucose to enter the cell and out of the blood stream. The dawn phenomenon occurs, but the shift in blood sugars is so minor and swift that it goes unnoticed.

However, for someone who can’t produce enough insulin or is insulin resistant, blood sugar control is not so finely tuned. The body takes longer to counteract the effect of blood sugars rising, and thus the dawn phenomenon appears more pronounced.

The dawn phenomenon is a normal process that happens everyone, every morning. However, the impression of the dawn phenomenon is directly linked with insulin sensitivity or production. Improving insulin sensitivity through a low-carb diet and/or intermittent fasting, will reduce morning fasting blood glucose, and lessen the dawn phenomenon effect.

There are also some other, helpful strategies you can use to soften the effect of dawn phenomenon :

Reduce stress hormones and balance circadian rhythm

  • Get to bed early and get a restful sleep. Try to get enough sleep that is right for you (this is different for everyone). Block out light and noise, and use stress reducing techniques to make sure you get deep, restful sleep.
  • Don’t use screens before bed. Try to stay away from blue light when the sun goes down. This is more difficult in the winter, so aim for at least 2 hours without screens before bed.

Reduce carbohydrate intake

  • Try to stick to fat and protein for your final meal of the day. This will minimise blood sugars before bed.
  • Additionally, try to eat low-carb for your first meal of the day. This is when your blood sugars will be highest, and thus more insulin resistance.

Deplete circulating and stored glucose

  • Incorporate exercise into your daily regime. Whether this is a gentle walk in the evening, or an early morning HIIT class, daily exercise is a powerful way to reduce blood sugars.
  • Practice intermittent fasting and avoid food at least 3 hours before sleep. This will balance your circadian rhythm and deplete glucose levels.

Every day makes a difference

It is important to note, that blood sugars  follow a downward trend throughout the day. For diabetics or non-diabetics, the highest fasting blood glucose is normally in the morning. This is why a HbA1c test is more reliable and revealing than a single blood sugar test, at a point in time

The HbA1c test is an average blood glucose level over a three month period, which clearly illustrates how your body responds to glucose.

So if in doubt or worried about your insulin sensitivity, ask your doctor about having a HbA1c test.

Lastly, please don’t worry too much about the dawn phenomenon. It is a normal response to the ebb and flow of our circadian rhythm and hormones. As you work towards regaining insulin sensitivity, your fasting morning blood sugars and HbA1c will naturally improve.

Like what you’re hearing?

Stay tuned for more guides, to help you with your health journey.

Take care 👋

I’m sure you’re curious about the science behind all this 🔬 Here are some recent medical publications about this topic:


September 8, 2021
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