Unless you’re a diabetic receiving treatment, when anything below 70 mg/dL (3.9 mmol/l) is considered hypoglycemic, a non-diabetic’s blood glucose level would need to be lower than 60 mg/dL (3.3 mmol/l) before being considered hypoglycemic, though you MAY begin to experience symptoms prior to reaching this level.

Two hours post prandial (after eating) a non-diabetic’s blood glucose level wouldn’t normally rise above about 140 mg/dL (7.8 mmol/l). I say normally as there are occasions when levels could go above this figure, such as if you were to have an underlying infection, you were going through a period of extreme stress, or you were taking certain medications which are known to cause a rise in blood glucose levels. (These medications often include steroids, such as those prescribed for the treatment of asthma, or for treating certain specific types of infection.)

Two hours post prandially, anything above 140 mg/dL (7.8 mmol/l) is considered hyperglycemic.

Fasting (after not eating overnight) blood glucose levels are considered ‘normal’ if they are between 70 and 99 mg/dL (3.9 and 5.5 mmol/l).

A fasting blood glucose level of between 100 and 125 mg/dL (5.6 and 6.9 mmol/l) would call for further testing as it MAY indicate pre-diabetes.

A fasting blood glucose level of more than 126 mg/dL (7.0 mmol/l) on two or more occasions … assuming the blood test was carried out correctly … would be indicative of diabetes mellitus.

Exercising DOES lower blood glucose levels, and MAY make you feel light-headed. Rarely it MIGHT cause you to faint, but this is more likely to happen if you’re diabetic and receiving treatment for your condition. (The medications offered are used to purposely lower blood sugar (glucose) levels, some by making your body’s cells less resistant to the effects of insulin that is still being produced by the pancreas, or to stimulate the pancreas to produce more insulin (this is in those with type 2 diabetes).)

Being hyperglycemic, in the vast majority of cases, means being diabetic. (There are other causes of being hyperglycemic, but it’s prolonged hyperglycemia that is diabetes.)

Hypoglycemia is when the blood sugar level drops down below 80, and there isn’t enough to support body functions. People might start to shake, get dizzy, get nauseous, have a seizure, or pass out. Treatment would be some hard candy or orange juice. This could be a medical emergency, and the person would need to go to the hospital.

Hyperglycemia is when the blood sugar is too high. Symptoms include losing weight unintentionally, being thirsty and hungry all the time, and having to urinate a lot. This could also be a medical emergency, and the person would need to go to the hospital.

Even in a person without diabetes, blood sugar will drop during exercise, and it will increase after eating. Diabetics have to constantly monitor their blood sugar levels, and adjust their eating and medicine in accordance to the results.