The dawn effect is the rise in blood glucose levels during the early morning hours. read on to learn why this occurs and how to manage it effectively.

Key takeaways

• The dawn effect is a natural phenomenon that causes a rise in blood glucose levels during the early hours of the morning, usually between 4am and 8am.
• It is caused by the release of hormones such as cortisol and growth hormone, which raise blood glucose levels to prepare our body for the day ahead.
• Managing the dawn effect through lifestyle modifications such as sleep prioritisation, regular exercise, stress management, essential nutrient intake, avoiding late meals, and optimising breakfast can improve glucose regulation.

Did you know that the dawn effect is a natural phenomenon that causes a rise in blood glucose levels during the early morning hours? Let's dive into why this occurs and what it means for you.

Why are my glucose levels high in the morning before eating?

The dawn effect refers to the natural rise in blood glucose levels that occurs in the early hours of the morning, usually between 4 am and 8 am. It is not related to food intake, exercise, or stress. This phenomenon is a normal part of our body's circadian rhythm, which regulates our sleep-wake cycle, hormone secretion, metabolism, and other physiological processes.

The dawn effect is caused by the release of hormones such as cortisol and growth hormone, which raise blood glucose levels to prepare our body for the day ahead. However, in some individuals, the dawn effect can be exaggerated and lead to high blood glucose levels, especially in people with diabetes or metabolic disorders.

Circadian rhythm and the dawn effect

The dawn effect is seen in individuals with poor circadian rhythms. Our circadian rhythm is partly regulated by the supra-chiasmatic nucleus, located close to the hypothalamus. This nucleus houses our clock genes, which play a vital role in promoting health, protecting against diseases, regulating energy metabolism, sleep, immunity, cancer prevention, and memory formation. Inadequate sleep length, quality, and regularity can impact our clock genes, leading to a disturbance in our circadian rhythm.

The role of hormones in the dawn effect

Hormones play a crucial role in the dawn effect. The release of hormones such as cortisol, growth hormone, ghrelin, and glucagon during the early hours of the morning can cause a rise in blood glucose levels.

Cortisol, for instance, peaks in the early hours of the morning, around 3am, to release glucose into the bloodstream and help stimulate the muscles, preparing us for the day ahead. Growth hormone secretion is another critical factor in the dawn phenomenon. It is released in pulses during deep sleep phases, and it stimulates the liver to increase blood glucose levels.

Additionally, glucagon and ghrelin hormones play a role in the dawn effect by increasing blood glucose levels and reducing insulin secretion. Understanding the complex interplay of hormones in the dawn effect is essential to managing glucose levels and improving overall metabolic health.

Who is at risk for the dawn effect?

Many people with diabetes display the dawn effect, but it can also be seen in about 10% of non-diabetic individuals. People with PCOS and other metabolic conditions such as central obesity, hyperlipidaemia, and metabolic syndrome are also at risk.

The dawn effect is more common in people with higher BMI, greater insulin resistance, larger waist circumference, poor sleep regulation, and higher levels of triglycerides.

Managing the dawn effect

The impact of the dawn effect on our long-term metabolic risk factors is unclear. However, research suggests that for optimal metabolic health, low glucose variability is best.

Here are some lifestyle factors that may help manage the dawn effect:

1. Prioritise sleep: Make sleep your top priority by ensuring you get enough sleep and maintaining a regular sleep pattern.
2. Exercise regularly: Regular physical activity helps regulate glucose levels and improve insulin sensitivity.
3. Manage stress: Stress management techniques such as mindfulness, yoga, and deep breathing can help reduce cortisol levels and improve insulin regulation.
4. Include essential nutrients: Nutrients such as magnesium, zinc, and vitamin D play a role in insulin sensitisation, glucose regulation, and sleep quality.
5. Avoid late meals: Studies have found that people who ate dinner at 6pm had significantly better glycaemic control during the following 24 hours than those who ate at 9pm.
6. Optimise breakfast: Increase protein and healthy fat content in your breakfast, and decrease the carb content. This can help slow digestion and reduce post-breakfast blood glucose spikes.
7. Check your blood glucose levels using a continuous glucose monitor (CGM): CGMs are a fantastic tool that allow you to see what your glucose levels are doing throughout the day, and can help you monitor the dawn effect

The dawn effect is a natural phenomenon, and its impact on our long-term metabolic health is unclear. However, managing the dawn effect through lifestyle modifications such as sleep prioritisation, regular exercise, stress management, essential nutrient intake, avoiding late meals, and optimising breakfast can improve glucose regulation.

Vively is a metabolic health app that uses CGMs and lifestyle modification to help you improve your glucose levels. It combines CGM data, wearable device data, dietitian support (if you opt in) and education to help you improve your overall health for the long-term.

Reference list

ScienceDirect. (n.d.). Dawn phenomenon. In ScienceDirect Topics. Retrieved from https://www.sciencedirect.com/topics/medicine-and-dentistry/dawn-phenomenon

American Diabetes Association. (n.d.). High morning blood glucose. Retrieved from https://diabetes.org/diabetes/treatment-care/high-morning-blood-glucose

Khardori, R. (2018). Type 2 Diabetes Mellitus. In R. A. F. El-Atat, S. A. McFarlane, & J. R. Sowers (Eds.), Endotext [Internet]. MDText.com, Inc. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK430893/