How to stop night-time blood sugar spikes

Managing your blood sugars during the day can be challenging in itself, but what happens when we go to sleep overnight?

At least during the day, you have the potential to manipulate your blood sugars by adjusting your insulin dosage to accommodate your food, exercise, hormones, and general daily life.

But stabilising your stubborn blood sugars overnight can be a completely different ball game, and you’re not alone. Many people living with diabetes struggle to tackle their blood sugar levels, but here are some handy tips to help you control them.


At first, this strange phenomenon can throw a spanner in the works as you become familiar with the notion of “blood sugar levels rise when you eat”, so why does our body not follow this rule overnight?

To understand the why and how, we must first acknowledge where glucose comes from, and where it goes when we sleep.

☀️ DURING THE DAY, the carbohydrates you eat are absorbed into the bloodstream as glucose. Some of this glucose goes to the liver, which acts as a warehouse to store it for later use.

🌙 OVERNIGHT our liver releases glucose into our bloodstream to keep us supplied until our breakfast meal. The liver can match the correct amount of glucose that’s being used with the amount of glucose it releases into the bloodstream. Therefore, blood sugars should remain constant.

However, the catalyst of this mechanism, insulin, is linked to the dawn phenomenon of high sugar levels. Insulin is in charge of relaying signals to the liver about how much glucose is needed.

In diabetes, either there isn’t enough insulin (type 1 diabetes) or there is enough insulin, but it can’t express the signal to the liver (type 2 diabetes).

The liver reacts to this lack of coordination by releasing glucose too quickly. Besides, hormone levels such as cortisol begin to rise in the early morning hours, which can lead to insulin sensitivity issues.

The ‘Somogyi effect,’ or rebound hyperglycaemia, is another cause of this phenomenon. If your blood sugar falls dangerously low in the middle of the night when you’re sleeping, your body can release hormones to “rescue” you.
The hormones do this by causing the liver to release more accumulated glucose than normal. However, in a person with diabetes, this system isn’t ideal, and the liver releases more sugar than is needed, resulting in a high blood sugar level in the morning. This is referred to as the Somogyi effect.

The easiest way to avoid the dawn phenomenon is to speak with your diabetes educator about how your sugar levels are performing at night. Your doctor may suggest eating a lighter breakfast, increasing your morning dose of insulin, or changing the type and timing of your diabetes medications.

For the Somogyi effect, your doctor may advise decreasing the dose of insulin that may be causing overnight lows, adding a carbohydrate snack before bed, or moving an evening workout to the afternoon.

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