70 is very low and is not usually a good level. The lower it get the more life threatening. So if you woke up with 50 or 60 something is off and should be fixed quickly. You can get seizures with too low of blood sugar, your personality tends to change (usually irrational and angry), impaired vision, fainting, hunger, anxiety (this one is common), heart palpitations, and tremor.I have some friends with this and people very close to me that have it. To combat this you take glucose tablets for accuracy, or some orange juice. In diabetes this is triggered by taking too much insulin or not eating in time.

I'm just gonna quote Wikipedia here:

"The level of blood glucose low enough to define hypoglycemia may be different for different people, in different circumstances, and for different purposes, and occasionally has been a matter of controversy. Most healthy adults maintain fasting glucose levels above 4.0 mmol/L (72 mg/dl), and develop symptoms of hypoglycemia when the glucose falls below 4 mmol/L.

"Throughout a 24 hour period blood plasma glucose levels are generally maintained between 4-8 mmol/L (72 and 144 mg/dL).[5]:11 Although 3.3 or 3.9 mmol/L (60 or 70 mg/dL) is commonly cited as the lower limit of normal glucose, symptoms of hypoglycemia usually do not occur until 2.8 to 3.0 mmol/L.(50 to 54 mg/dl).

"Obvious impairment may not occur until the glucose falls below 40 mg/dL (2.2 mM), and many healthy people may occasionally have glucose levels below 65 in the morning without apparent effects. Since the brain effects of hypoglycemia, termed neuroglycopenia, determine whether a given low glucose is a "problem" for that person, most doctors use the term hypoglycemia only when a moderately low glucose level is accompanied by symptoms or brain effects.

"In nearly all cases, hypoglycemia that is severe enough to cause seizures or unconsciousness can be reversed without obvious harm to the brain. Cases of death or permanent neurological damage occurring with a single episode have usually involved prolonged, untreated unconsciousness, interference with breathing, severe concurrent disease, or some other type of vulnerability. Nevertheless, brain damage or death has occasionally resulted from severe hypoglycemia.

"Like most animal tissues, brain metabolism depends primarily on glucose for fuel in most circumstances. A limited amount of glucose can be derived from glycogen stored in astrocytes, but it is consumed within minutes. For most practical purposes, the brain is dependent on a continual supply of glucose diffusing from the blood into the interstitial tissue within the central nervous system and into the neurons themselves.

"Therefore, if the amount of glucose supplied by the blood falls, the brain is one of the first organs affected. In most people, subtle reduction of mental efficiency can be observed when the glucose falls below 65 mg/dl (3.6 mM). Impairment of action and judgment usually becomes obvious below 40 mg/dl (2.2 mM). Seizures may occur as the glucose falls further. As blood glucose levels fall below 10 mg/dl (0.55 mM), most neurons become electrically silent and nonfunctional, resulting in coma. These brain effects are collectively referred to as neuroglycopenia.

"The importance of an adequate supply of glucose to the brain is apparent from the number of nervous, hormonal and metabolic responses to a falling glucose level. Most of these are defensive or adaptive, tending to raise the blood sugar via glycogenolysis and gluconeogenesis or provide alternative fuels. If the blood sugar level falls too low the liver converts a storage of glycogen into glucose and releases it into the bloodstream, to prevent the person going into a diabetic coma, for a short period of time.

"Brief or mild hypoglycemia produces no lasting effects on the brain, though it can temporarily alter brain responses to additional hypoglycemia. Prolonged, severe hypoglycemia can produce lasting damage of a wide range. This can include impairment of cognitive function, motor control, or even consciousness. The likelihood of permanent brain damage from any given instance of severe hypoglycemia is difficult to estimate, and depends on a multitude of factors such as age, recent blood and brain glucose experience, concurrent problems such as hypoxia, and availability of alternative fuels. It has been frequently found that those Type 1 diabetics found "dead in bed" in the morning after suspected severe hypoglycemia had some underlying coronary pathology that led to an induced fatal heart attack. Recently, several of these individuals found "dead in bed" were wearing Continuous Glucose Monitors, which provided a history of glucose levels prior to the fatal event. It has been found in several cases, that the fatal event was preceded by at least two hours of blood glucose levels under 40 mg/dl, possibly lower as the continuous glucose monitors are not accurate at levels below 40 mg/dl. The individuals failed to respond to the audible alarms produced by the continuous glucose monitor which may have been "alarming" for many hours prior to the fatal event. The vast majority of symptomatic hypoglycemic episodes result in no detectable permanent harm."

My morning blood sugar level is 68. I can't say that I feel harmed by this. Maybe the doctors are wrong, but they don't appear the least bit concerned about my 68. If I'd acted dizzy at this number, I think then maybe they'd worry. But, at 68, I have a ton of energy and don't feel weak. My Dad blood pressure runs 68 in the morning, too. He's in his mid 60's and looks at least ten years younger than his peers and has no health issue. I can't detect any cognitive decline from having a blood sugar reading of 68 for his entire life. If he went down to 62, I think I'd be telling a different story. I think our pancreas' don't like to waste anything. Our blood pressure runs low too: 90/52. They Doctors worry about the 52, but then when they find out that I have a life time history and a family history of low blood pressure, they don't worry about it. My families body temp. comes in at between 96.5 to 97.5. We're designed to have low numbers. My husband's family that starts out young with higher morning numbers: blood sugar at 80 are the ones that are thin and diabetic by 55 and they are very forgetful by their mid 60's.

anything below 70 is low! apparently the lower the more damage! unless it is corrected. the old man's was 26 one morning! that scared me!