What is it; does it affect you and what can you do about it?
Dawn phenomenon is a rise in blood sugar due to a surge in hormone secretions during the night or early morning, which trigger the liver to move sugar into the bloodstream. It is the body’s way of preparing us for the day by giving us plenty of sugar for energy. People who don’t have diabetes aren’t bothered by this because their pancreas releases the appropriate amount of insulin to balance out the extra sugar. This sugar is then sent around the body to the cells that need it, to give energy for bodies and minds for the day ahead.
It can be problematic for diabetics because the normal dose of Basal (background) insulin won’t be able to deal with unexpected and unpredictable events like this. People who use insulin pumps can change the ratio of insulin to counteract this, when they have identified the time that dawn phenomenon starts to affect them, if it is a regular occurrence. Left unattended it can cause high blood sugar for several hours during the early morning and need corrective action with insulin or exercise, or both. I always have it if I am stressed or if I have an early morning start even if it something nice like going on holidays. It would be easier to deal with if it was a permanent thing but it is intermittent. I can have it for a week and then it disappears and comes back again days or weeks later.
Raised blood sugars due to dawn phenomenon may respond quicker to insulin or exercise than high glucose due to other things, which can result in hypos.
It’s important to be sure that high blood sugar in the morning is dawn phenomenon. It could be due to any or a combination of the following:
1.Insufficient insulin. Some long-acting (Basal) insulins don’t work well for a full 24 hours; they peter out in the last few hours. If they are given in the morning it can give rise to higher blood sugar prior to the next dose. Giving it in the evening may help. Always consult your Doctor before changing your insulin regime. Insulins, like Tresiba, have come on stream recently which give more even coverage across a 24 hour period. Ask your Doctor about this if you think that you may benefit from them.
2. High blood sugar for most of the night as a result of incorrect insulin for carbs eaten before bed or stress.
3. Normal blood sugar early in the night, but an increase later in the night due to slow release carbs eaten before going to bed.
4. Having a hypo http://theartisandiabetic.ie/hypoglycemia-hypo/ during the night, where the liver tries to correct it by releasing hormones resulting in raised blood sugar levels. These correct the hypo but can result in high blood sugar for the remainder of the night. This is called the Somogyi effect or rebound effect. It is named after Michael Somohy the researcher who first identified it.
The only way to be sure it is actually dawn phenomenon is to investigate when glucose levels increase during the night, using either a continuous glucose monitor or by testing blood sugar at different times during the night for several nights in a row. It needs to be done when you don’t have a cold or flu, because these can temporarily cause blood sugar increases.
- If sugar is below the target range early in the night and high in the morning I would suspect the Somogyi effect. Reducing insulin at the last meal or eating a suitable snack before bed should prevent this happening.
- If sugar is normal during the night and goes high towards the morning then dawn phenomenon could be the culprit. Reducing carbs before going to bed and changing insulin time or adjusting insulin pump ratio may help to counteract this.