Know why it happens. Why do some people experience a blood glucose crash in the middle of the night? This is a fairly common problem for many people but they may not be aware of it. When blood glucose levels fall below 70 mg/dl during sleep, it is called nocturnal hypoglycemia according to John's Hopkins Medicine. When this happens, the person's blood sugar is said to experience a sudden crash. This crash can cause the cortisol levels or stress hormone to spike up which in turn can lead to disrupted sleep, night mares and symptoms of insomnia. This typically happens in the middle of someone's sleep at night which is why it is called nocturnal hypoglycemia. If a person is not aware of this condition, it may be dangerous but otherwise this condition is preventable with careful planning. In this article we will discuss in detail the factors which cause blood glucose levels to fall at night. What Causes Blood Sugar To Crash Late In The Night? Blood sugar levels can drop at night for a number of reasons, including: If a person has been diagnosed with nocturnal hypoglycemia and still experiences blood sugar crashed at night, these factors are responsible for it. But, blood sugar can also reduce for people who do not have hypoglycemia. Let us look at both the factors: Who Are At Risk Of Nocturnal Hypoglycemia? Nocturnal hypoglycemia can mostly happen to people who: