Causes of High and Low Blood Sugar

Even if you've been careful to take care of yourself and manage your type 2 diabetes, there may still be times when your blood sugar is too high or too low.

Over time, high blood sugar can lead to serious problems or a medical emergency. When your blood sugar is too low, you can get shaky and weak. If your blood sugar gets very low, you could pass out (lose consciousness).

High blood sugar can happen if you:

• Skip a dose of your diabetes medicine or skip a required dose of insulin.
• Eat too much.
• Are stressed or ill (such as with a bad case of the flu) or if you have an infection, especially if you are not eating or drinking enough.
• Are taking medicines that raise blood sugar as a side effect, such as sleeping pills, some anti-inflammatory medicines (corticosteroids), and some decongestants.

Being pregnant can also make your blood sugar levels go up.

If you take insulin, you may have some mornings when your blood sugar level is very high, even if it was low when you went to bed. This called the Somogyi effect. Talk with your doctor if this happens. You may need to check your blood sugar during the night to find out why your levels are high in the morning.

You aren't likely to get low blood sugar unless you take insulin or some kinds of oral medicines. You may get low blood sugar if you:

• Take too much oral medicine in a day, take your doses too close together, or take your full dose of medicine when you are not going to eat your usual amount of food.
• Exercise too much without eating enough food.
• Skip a meal.
• Drink too much alcohol, especially on an empty stomach.
• Take other medicines that can lower blood sugar levels, such as large doses of aspirin and medicines for mental health problems.
• Have problems with your kidneys.
• Start to have other problems with your glands and hormones, such as Addison's disease or hypothyroidism.