Hypoglycemia

• Hypoglycemia, or an abnormally low level of glucose in the blood, can lead to fainting. When a person with diabetes takes too much insulin or medication or doesn't enough eat enough, he may inadvertently lower his level of glucose (sugar) to a dangerous level. According to Your Total Health, this may cause loss of consciousness, resulting in a fainting spell. The brain needs glucose for nourishment, and the body needs adequate levels to regulate blood pressure. Fainting happens when the brain is deprived or when blood pressure drops too low, and the problem is compounded with the overrelease of adrenalin and cortisol in reaction to the lack of glucose.
  
  

Hyperglycemia

• Hyperglycemia, or an abnormally high level of glucose in the blood, can lead to fainting and diabetic coma. When someone with diabetes eats too much of an unhealthy food or skips her medication or insulin injection, her blood sugar can rise to a dangerous level. Your Total Health warns that this may cause her to faint and slip into a diabetic coma. Prior to fainting, she will appear to be confused and possibly incoherent.
  
  

Cardiac Problems

• According to Your Total Health, cardiac problems are one of the long-term side effects of diabetes. Fainting can be a symptom of many of these heart-related conditions because they often interrupt the flow of blood to a person's brain. When someone with diabetes faints and her glucose levels are normal, she should be evaluated for possible heart problems that could be the underlying cause.
  
  

Nerve Damage

• Nerve damage is a common long-term effect of diabetes. Your Total Health says that if this damage is neurological, it can trigger fainting spells in the affected person because of the disturbance to the brain's proper function.