Many factors can cause high fasting blood sugar, which is when a person has too much sugar in their bloodstream after eight hours of not eating. Some common causes include too much insulin or blood pressure medication taken at night, a bodily process known as the "dawn phenomenon," and a person's basal secretion processes being impaired. Fasting blood sugar is usually measured after a person wakes up in the morning, before eating breakfast.
Taking too much blood pressure medicine or insulin at night can cause a rise in fasting blood sugar. While the purpose of taking insulin is to lower a person's blood glucose level, if you take too much before bedtime, your body can raise your blood sugar at night. The same phenomenon can occur if a person takes too much blood pressure medication: the body can increase blood pressure at night. People experiencing this phenomenon may wake up in the middle of the night with a pounding heart and feeling dizzy or nauseous. If a person experiences this, they should talk to a doctor about adjusting their medications or their dosages.
An occurrence known as the "dawn phenomenon" can also cause high fasting blood sugar. Before the person wakes up, the body prepares for action by releasing blood sugar that has been stored in the liver. Due to this, the person will be able to get up and be active in the morning. In some people, this can cause fasting blood sugar to rise too high. To counteract this, a person can have a snack before bed to prevent the liver from releasing sugar during the pre-dawn hours.
A person who does not have a proper basal secretion process may also have high fasting blood sugar. Typically, a person's body will secrete a small amount of insulin periodically so that the body can use blood sugar between meals. If that process is damaged, the liver can recognize the lack of insulin as a signal to start secreting more sugar into the bloodstream. To reverse this, a person may have to take insulin. Before taking any steps to correct this problem, a patient should see a doctor so that she can diagnose the problem and prescribe insulin or other medications.
A person can often control high fasting blood sugar by eating a snack before bedtime, changing the schedule of medications taken at night, or exercising before bedtime. However, it's important to talk to a doctor for the best advice and guidance for managing your blood sugar, especially if it means changing the timing or dosage of a prescribed medication. Interestingly, a person with high fasting blood sugar may have normal blood glucose for the rest of the day. In contrast, a person with normal fasting blood sugar may struggle with high blood glucose throughout the day. Therefore, a person who is concerned about their blood glucose level should check it several times to get the most accurate reading.