Question:
I noticed I have diabetes since March 2011, and now I am trying my best to control it by dieting. My non-fasting blood sugar is between 8 and 18 mmol/L, with 18 mmol/L being the highest.
I wonder why my blood sugar reading early in the morning is higher, about 11 mmol/L at 7:30 am, than before bed.
Are these readings dangerous?
Your morning blood sugar of 11 mmol/L is about 198 mg/dL, which is high. Your after-meal readings of 11.6 mmol/L and 13.4 mmol/L are also above common diabetes targets.
Blood sugar can be higher in the morning because of the dawn phenomenon, late-night carbohydrates, illness, stress, poor sleep, or not enough diabetes treatment overnight.
These readings are not automatically an emergency if you feel well, but they are too high to ignore. Since your glucose has reached 18 mmol/L, you should contact your doctor for a treatment review, not rely on diet alone.
Answer by Dr. Albana Greca, MD, MMedSc
Hello,
I read your question carefully. Your readings show that your blood sugar is running higher than recommended at several times of the day. Diet is very important, but when readings remain this high, diet alone may not be enough.
Morning high blood sugar is common in people with diabetes. The body naturally releases hormones in the early morning, such as cortisol and glucagon. These hormones tell the liver to release glucose so the body has energy to wake up.
In people without diabetes, insulin usually keeps this rise controlled. In diabetes, the body may not have enough insulin effect, so the morning reading may rise. This is often called the dawn phenomenon.
Other reasons include a high-carbohydrate dinner, late-night snacks, poor sleep, stress, infection, dehydration, missed medication, or needing a change in diabetes treatment.
Yes. Here is what your readings mean approximately in mg/dL:
You can check future readings with this mmol/L to mg/dL blood sugar converter.
For many nonpregnant adults with diabetes, common targets are about 80–130 mg/dL before meals and less than 180 mg/dL 1–2 hours after starting a meal. Your readings are above these common targets, so your diabetes plan needs review.
They are high enough to take seriously. A single reading of 11–13.4 mmol/L may not always mean an emergency, but repeated high readings can increase the risk of dehydration, tiredness, blurry vision, infections, and long-term diabetes complications.
A reading of 18 mmol/L is more concerning, especially if it happens repeatedly or if you feel unwell. If your blood sugar is around 13.9 mmol/L / 250 mg/dL or higher, ask your doctor whether you should check ketones, especially if you are sick, vomiting, very thirsty, or losing weight.
Read more here: dangerous blood sugar levels.
You may also compare your numbers with this guide: blood sugar levels by time of day.
Yes, diet can help, but it should be part of a full plan. In the evening, try to avoid large portions of rice, bread, potatoes, sweets, fruit juice, and late-night snacks. A balanced dinner with vegetables, lean protein, and a moderate carbohydrate portion may help.
A short walk after dinner may also help some people lower after-meal and overnight glucose, if your doctor says exercise is safe for you.
Seek urgent medical help if you have vomiting, dehydration, confusion, severe weakness, fast or deep breathing, chest pain, severe abdominal pain, fruity-smelling breath, moderate or large ketones, or blood sugar that stays very high despite following your diabetes plan.
If your meter reads very high repeatedly, or your blood sugar is near 18 mmol/L or higher with symptoms, do not wait for a routine appointment.
Your readings show that diabetes is not yet well controlled. Morning sugar of 11 mmol/L and post-meal readings above 11 mmol/L need follow-up. Please take your blood sugar log to your doctor so your diet, activity, HbA1c, and treatment plan can be adjusted safely.
Educational safety note: This answer is for general diabetes education only. It does not replace personal medical advice, diagnosis, or treatment. Do not start, stop, or change diabetes medicine, insulin, herbs, or supplements without speaking with your healthcare provider.
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