Dawn Phenomenon: Identifying And Managing Symptoms: HealthifyMe

When managing diabetes, it is ideal to maintain morning blood glucose levels between 70 and 99 milligrams per deciliter (mg/dL). However, people with diabetes often find that their early-morning blood sugar is high. These early-morning blood sugar spikes occur due to a relatively common event called the dawn phenomenon, affecting approximately 50% of people living with either type 1 or type 2 diabetes.

If your morning blood sugar consistently stays higher than it should, it can significantly impact your overall health. Therefore, it’s crucial to manage the dawn phenomenon to reduce the risk of diabetes-related complications.

What is the Dawn Phenomenon?

The dawn phenomenon is the increase in blood sugar levels occurring in the early morning hours, typically between 3:00 a.m. and 8:00 a.m. There is also an extended dawn phenomenon, which involves hyperglycemia persisting into the later morning hours. Dawn phenomenon happens in both type 1 and type 2 diabetes across all age groups, including those over 70 with type 2 diabetes.

The dawn phenomenon in diabetes can raise blood sugar levels to potentially dangerous levels. Untreated high blood sugar due to the dawn phenomenon can lead to increased A1C levels. The A1C level shows the percentage of haemoglobin with glucose attached. It’s a crucial tool for people with diabetes to manage their condition. The results are in percentages, and higher percentages mean higher average blood sugar levels. Regular A1C tests help keep track of how well diabetes is being controlled.

Higher A1C levels due to the dawn phenomenon increase the risk of complications, especially with consistently elevated levels over several years. It can lead to;

  • Diabetic retinopathy (Over time, this can lead to vision problems and even blindness if left untreated)
  • Nephropathy or damage to the small blood vessels in the kidneys
  • Neuropathy
  • Heart disease


The dawn phenomenon, occurring between 3:00 a.m. and 8:00 a.m., involves increased blood sugar levels in type 1 and type 2, affecting all age groups, including those over 70 with type 2 diabetes. The extended dawn phenomenon extends hyperglycemia into later morning hours. Unmanaged, it can lead to dangerous blood sugar levels, emphasising the need for management to prevent complications like retinopathy, nephropathy, neuropathy, and heart disease.

The Dawn Phenomenon vs. the Somogyi Effect

The dawn phenomenon and the Somogyi effect are two common reasons why people with diabetes might wake up with high blood sugar. While both involve hormone-triggered glucose production, there are notable differences. The Somogyi effect is linked to a late-night episode of low blood sugar, leading to an early morning rise in glucose levels. However, the dawn phenomenon can happen without experiencing a hypoglycemic episode during the night.

The dawn phenomenon happens when there is a decrease in the body’s natural insulin secretion or when the impact of externally administered insulin from the previous day diminishes. It occurs alongside a natural increase in hormones that counteract insulin. The Somogyi effect involves low blood sugar levels at night, prompting the body to release extra glucose in response. It can lead to waking up in the morning with elevated blood sugar levels.

The dawn phenomenon is more prevalent than the Somogyi effect. While their insulin treatments vary, the most effective way to prevent both the dawn phenomenon and the Somogyi effect is by maintaining optimal diabetes control through diet and exercise. 


The dawn phenomenon and the Somogyi effect cause high morning blood sugar in people with diabetes. The Somogyi effect follows nighttime hypoglycemia, resulting in a rise in morning glucose. The dawn phenomenon, unrelated to night hypoglycemia, involves decreased insulin, hormonal changes, and higher morning blood sugar. It is more common than Somogyi. You can manage both with optimal diabetes control through insulin therapy, diet, and exercise. 

Symptoms of Dawn Phenomenon

The primary symptom of the dawn phenomenon is high morning blood sugar levels, known as hyperglycemia. Hyperglycemia occurs when your blood sugar reading exceeds 180 mg/dL. You may experience the following symptoms when waking up, depending on how high your blood sugar is:

  • Increased thirst: Polydipsia, or excessive thirst, is an abnormal urge to drink fluids continuously, usually in response to fluid loss in the body. It may come with a dry mouth (xerostomia).
  • Frequent urination
  • Blurry vision
  • Irritability
  • Abdominal discomfort
  • Nausea
  • Fatigue


The dawn phenomenon is marked by high morning blood sugar levels, known as hyperglycemia (exceeding 180 mg/dL). Symptoms upon waking up vary with blood sugar levels, including increased thirst (polydipsia), frequent urination, blurry vision, irritability, abdominal discomfort, nausea, and fatigue.

Causes of Dawn Phenomenon

During early morning hours, typically between 3 a.m. and 8 a.m., the body releases a surge of cortisol and growth hormone. These hormones signal the liver to increase glucose production to provide energy for waking up. This increase in glucose raises blood sugar levels. In people without diabetes, the pancreas releases enough insulin to control blood sugar. However, in diabetes, not enough insulin is produced, or the body doesn’t respond well to it, leading to higher blood sugar levels during this time.

The activity of externally administered insulin often starts to decrease in the early morning hours (depending on the type of insulin and administration route). As a result, there is insufficient opposition to hepatic activity, leading to hyperglycemia. Those with type 2 diabetes are more susceptible to early morning dysregulation of hepatic glucose production due to their inability to generate compensatory insulin secretion.


Between 3 a.m. and 8 a.m., cortisol and growth hormone surges prompt the liver to boost glucose production for morning energy, raising blood sugar. Non-diabetics release sufficient insulin to regulate it. People with diabetes lacking insulin or facing resistance experience elevated blood sugar. External insulin activity diminishes in the early morning, which is insufficient to counter hepatic activity and causes hyperglycemia. 

Management of Dawn Phenomenon

Since the dawn phenomenon is typically a persistent concern, neglecting or not treating it may result in consistently elevated blood sugar for several hours daily. This prolonged elevation can heighten the risk of diabetes complications over time. To prevent or correct high blood sugar in the morning, you can take the following measures:

Find if You Have the Dawn Phenomenon or the Somogyi Effect

To determine the correct cause of waking up with high blood sugar, you need to test your blood sugar around 2 or 3 a.m. for several nights. If your levels are consistently low during that time, it’s likely the Somogyi effect. If the levels are high, it may be the dawn phenomenon. Identifying the root cause will help your doctor develop a personalised plan to address the issue.

At HealthifyMe, nutritionists take into account individual preferences, lifestyle, and health goals when developing personalised diet plans. This approach ensures that the plan is both realistic and sustainable for each individual.

Track Blood Sugar Levels

The primary indicator of the dawn phenomenon is elevated morning blood sugar. Thus, effectively managing this phenomenon requires closely monitoring blood sugar levels. Tracking provides valuable insights into blood sugar levels at various times, including the early morning rise. One can use a HealthifyMe CGM (continuous glucose monitor), which measures blood glucose throughout the day, providing real-time results with every meal and workout. 

Regular tests are essential, but a CGM automates the process effectively. This device operates day and night, allowing you to track and monitor blood glucose levels anytime and anywhere effortlessly.

Avoiding Carbohydrates Around Bedtime

Consuming a carb-filled snack or meal before bedtime can elevate blood sugar levels, potentially worsening the effects of the dawn phenomenon. Evenly distribute your carbohydrate intake throughout the day, avoiding a large portion of carbs at dinner to prevent excessive glucose release at night.

Consider having a small, balanced bedtime snack with complex carbohydrates and protein to stabilise blood sugar levels. However, overeating may cause indigestion and disrupt sleep. It’s advisable to consume carbs one to four hours before sleep rather than immediately before bedtime. Also, avoid high-sugar foods and beverages, particularly close to bedtime, as they can cause rapid blood sugar spikes. 


Engaging in evening exercise can lower blood sugar levels, but be cautious to avoid overexertion, which may lead to nighttime hypoglycemia. Opt for lighter physical activities like walking or yoga. If you have high morning blood sugar, being active during this time can also help lower your blood sugar.

Exercise enhances insulin sensitivity, promoting more stable blood sugar levels throughout the day. Additionally, incorporating stress-reduction techniques like meditation, deep breathing, or yoga into your daily routine can further contribute to overall blood sugar management.

Insulin therapy

Choosing an insulin regimen should be personalised for each patient, considering the extent of the dawn phenomenon. Continuous insulin infusion has shown superior control, possibly because it can counteract the dawn phenomenon with an early morning bolus, unlike long-acting insulin formulations.

In type 1 diabetes, achieving precise insulin control requires considering the dawn phenomenon as well as nocturnal hypoglycemia. Adjusting insulin based solely on early morning fasting glucose levels might result in administering a larger than necessary dose if the dawn phenomenon’s magnitude is not considered.

Consistent Dinner Timings

While some may consider skipping dinner, it’s essential to have dinner in the evening to avoid hypoglycemia. Consuming meals at regular intervals allows for better insulin management and prevents large spikes or drops in blood sugar. You can avoid high sugar levels by choosing smaller meals with a higher protein-to-carbohydrate ratio and eating dinner earlier rather than later.


Neglecting the persistent dawn phenomenon can lead to a prolonged rise in daily blood sugar, increasing the risk of diabetes complications. To address this, testing blood sugar at 2 or 3 a.m. helps distinguish between the dawn phenomenon and the Somogyi effect, guiding personalised treatment plans. HealthifyMe’s nutritionists tailor diet plans to individual preferences, ensuring practical and sustainable solutions. Tracking blood sugar with a CGM offers real-time insights while avoiding bedtime carbohydrates, engaging in evening exercise, and personalised insulin therapy contribute to effective management. Consistent dinner timings further stabilise blood sugar levels. 

HealthifyMe Suggestion

An ideal way to help prevent the dawn phenomenon is to have a high fibre, low carb, low fat snack at bedtime. 

An ideal snack would be 4-5 almonds or walnuts with a glass of skimmed milk. This can be amped up further by adding a pinch of turmeric into the milk. It’s also important to have dinner at a relatively consistent time and remember to keep your carbs at dinner on the lower side but to never skip the meal entirely.

The Final Word

The dawn phenomenon, characterised by high blood sugar levels between 3:00 a.m. and 8:00 a.m., poses a concern for people with diabetes. To effectively manage this phenomenon, one can take measures such as identifying its presence through nighttime blood sugar testing, utilising HealthifyMe’s personalised diet plans, and monitoring blood sugar levels with continuous glucose monitors (CGM). Consistently adhering to dinner timings and prioritising meals with a higher protein-to-carbohydrate ratio significantly contribute to maintaining stable blood sugar levels. 

Precise control, especially in type 1 diabetes, depends on optimal insulin therapy tailored to individual dawn phenomenon characteristics. HealthifyMe’s comprehensive support, with nutritional guidance and continuous glucose monitoring, actively aids in sustaining optimal diabetes control and minimising the risk of complications.

Disclaimer: The purpose of this article is just to disperse knowledge and raise awareness. It does not intend to replace medical advice from professionals. For further information, please contact our certified nutritionists Here.

Research Sources

The dawn phenomenon and the Somogyi effect – two phenomena of morning hyperglycemia

Dawn phenomenon

Thirty Years of Research on the Dawn Phenomenon: Lessons to Optimise Blood Glucose Control in Diabetes

Exploring the Impact of Dawn Phenomenon on Glucose-Guided Eating Thresholds in Individuals With Type 2 Diabetes Using Continuous Glucose Monitoring: Observational Study

Frequently Asked Questions (FAQs)

Q: How long does the dawn phenomenon last?

A: The “dawn phenomenon” is high blood sugar episodes in people with diabetes, typically happening from 3:00 a.m. to 8:00 a.m. It occurs during the early morning hours, lasting about 5 hours.

Q: Can the dawn phenomenon occur in non-diabetics?

A: Non-diabetic people generally regulate their blood sugar levels well through the body’s natural insulin response, and the dawn phenomenon is usually not a concern. Some studies suggest that a mild form of the dawn phenomenon may occur in individuals without diabetes. However, the increase in blood sugar is usually minimal and within normal ranges.

Q: How to treat the dawn phenomenon naturally?

A: Nearly everyone with diabetes experiences the dawn phenomenon, but there are ways to manage it. One way is to avoid eating carbohydrates before bedtime. Another approach is to take insulin right before going to bed instead of earlier in the evening. Consulting with your doctor about adjusting insulin or other diabetes medicines can also help manage the phenomenon. Using an insulin pump overnight is another option to consider.

Q: What foods prevent the dawn phenomenon?

A: To prevent morning blood sugar spikes, one strategy is to limit your intake of carbohydrates in the evening. Instead of consuming trans or saturated fats from hard-to-digest animal sources, choose monounsaturated fats derived from plants, which are easier to digest. Non-starchy vegetables and high-fibre foods help keep blood sugar levels stable.

Q: How and why does the dawn phenomenon occur?

A: The dawn phenomenon, or dawn effect, is when blood sugar levels naturally rise in the early morning hours, usually between 3 a.m. and 8 a.m. The dawn phenomenon happens because of hormonal changes in the early morning. Growth hormone and cortisol levels increase during the night and peak in the early morning, reducing insulin sensitivity and promoting glucose production in the liver. In people with diabetes, especially those with insufficient insulin or insulin resistance, this can lead to higher fasting blood sugar levels during the morning.

Q: How many hours does the dawn phenomenon last?

A: The “dawn phenomenon” refers to episodes of high blood sugar in people with diabetes, usually between 3:00 a.m. and 8:00 a.m. It typically occurs during the early morning hours, spanning approximately 5 hours.

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