What is the definition or description of: low blood glucose?

Sugar level too low: Glucose is the main form of sugar in the body. For most people, a normal fasting glucose level is 60-100, so anything less than this would be low. For people with diabetes, the desired range for their glucose level varies, but many try to keep it between 80 and 120. Anything less than 70 would be considered too low. If someone runs higher than this, they may feel bad even with a glucose ~ 100.

<60: Traditionally low blood sugar was defined as < 60. There is some consideration for raising the cut off to 70. Raising to 70 in the elderly may avoid the potential complications related to hypoclygemia.