Starting the day with a high blood glucose makes getting things under control much more difficult than starting the day with an ‘on target’ glucose. If the first priority is avoiding hypoglycaemia, the second is certainly getting control of the morning glucose.
What causes high morning blood sugar levels?
- The black line in the figure above is an example of someone going to bed with a high glucose (around 10) and waking up with a similarly high glucose. In situations like this, it is worth looking at how effective the previous evening’s tea time dose of quick-acting insulin had been. The background insulin is supposed to keep the glucose steady overnight and it appears to have done so (see step 4 [page 8] for more details on assessing the effectiveness of mealtime insulin doses).
- The white line is an example of not enough background insulin. The glucose starts off fine at bedtime but rises progressively through the night. This may be because the dose of background insulin is too low. In people who take their background insulin in the morning, it may be because it is wearing off through the night (this happens in about a quarter of people on once a day background).
- The ‘Dawn Phenomenon’ is a situation where blood glucose levels rise significantly between 3am and waking. This affects some patients more than others and is caused by the early morning rise in hormones (cortisol and growth hormone) which make the body more resistant to the effects of insulin.
- Firstly it is important to make sure that pre-bed glucose readings are generally OK.
- If it appears to be related to a lack of background insulin, this can be dealt with by increasing the dose or splitting the dose in two (see step 3, page 7).
- The Dawn Phenomenon can be tricky to deal with – sometimes an insulin pump is the best option.