While we sleep our body goes through many processes. One of the processes is how the ‘dawn phenomenon’ occurs. The dawn phenomenon or ‘dawn effect’ refers to the natural rise in blood glucose because of a surge of hormones that have been secreted through the night.
Most of these are counter-regulatory hormones including epinephrine, glucagon and cortisol. These hormones jump start the process of converting glycogen stores in the liver into glucose which are released into the blood – a process experts refer to as glycogenolysis.
The body may only need a very small amount of insulin when your body is in its deep sleep cycle, for example between midnight and 3 am. Then starting at 3am to 8am the liver will release sugar to prepare the body for the day’s activities.
However, if insulin levels have reduced to a very low level overnight, the body is no longer capable of keeping blood glucose levels in check. Therefore, upon waking, having high levels of blood sugar may become a common occurrence.
If you’re diabetic this rise in your morning blood sugar levels can pose a problem. It may be caused by insulin resistance, which is a condition that makes the muscle cells not use the hormone insulin as effectively as it should.
The presence of insulin resistance also adversely affects the ability of the liver to store, process or release glucose in the blood, especially at night. Normally the liver continues to release small amounts of sugar into the blood, even if the person hasn’t just eaten.
For type 2 diabetics, their liver is releasing more sugar into the blood than what is needed during the night. Therefore, if their hormones are causing blood sugar levels to elevate, the problem is compounded by the liver, which is releasing even more sugar into the blood.
Unlike having elevated blood sugar levels during or after mealtime, high fasting blood glucose levels cannot be treated with just exercise and diet. It must be treated with medication prescribed by a doctor. Some diabetics experience high blood sugar levels in the morning because their medication has diminished.
How to Prevent the Dawn Phenomenon
- Do not eat carbohydrate-containing foods at bedtime.
- Make the necessary adjustments to your diabetes medication.
- Ask your doctor if your medication needs changing or adjusting.
- Instead of taking your medication at dinnertime, your doctor may recommend you take it at bedtime.
Some diabetics choose to take their fast-acting insulin the moment they wake up to help them cope with the dawn phenomenon. Others prefer to exercise as soon as they wake up, to help their bodies cope with the mornings high blood sugar levels.
A Check You Can Do
How can you tell if the cause of your morning high blood sugar levels is the dawn phenomenon? One way is to check your blood glucose levels between 3 am to 5 am. You should record your readings for several consecutive days. If your blood glucose levels are instead too low over the consecutive days, then another problem called the Somogyi effect is more likely to blame.
However, if blood glucose levels have been high when measured over the consecutive days, and at the same time, then yes, it’s probably the dawn phenomenon you’re experiencing.
Another way to determine whether the the dawn phenomenon is occurring, is to check your blood sugar before bed, in the middle of the night and again in the morning. Aside from manually checking your blood sugar levels, some experts also recommend using a CGM or Continuous Glucose Monitoring System.