Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even higher values such as 13.9–16.7 mmol/L (~250–300 mg/dL). A subject with a consistent range between ~5.6 and ~7 mmol/L (100–126 mg/dL) (American Diabetes Association guidelines) is considered slightly hyperglycemic, and above 7 mmol/L (126 mg/dL) is generally held to have diabetes. For diabetics, glucose levels that are considered to be too hyperglycemic can vary from person to person, mainly due to the persons renal threshold of glucose and overall glucose tolerance. On average, however, chronic levels above 10–12 mmol/L (180–216 mg/dL) can produce noticeable organ damage over time. Signs and symptoms
The degree of hyperglycemia can change over time depending on the metabolic cause, for example, impaired glucose tolerance or fasting glucose, and it can depend on treatment. Temporary hyperglycemia is often benign and asymptomatic. Blood glucose levels can rise well above normal and cause pathological and functional changes for significant periods without producing any permanent effects or symptoms. During this asymptomatic period, an abnormality in carbohydrate metabolism can occur, which can be tested by measuring plasma glucose. Chronic hyperglycemia at above normal levels can produce a very wide variety of serious complications over a period of years, including kidney damage, neurological damage, cardiovascular damage, damage to the retina or damage to feet and legs. Diabetic neuropathy may be a result of long-term hyperglycemia.
This is done by a combination of proper diet, regular exercise, and insulin or other medication such as metformin, etc.Those with hyperglycaemia can be treated using sulphonylureas or metformin or both. These drugs help by improving glycaemic control. Dipeptidyl peptidase-4 inhibitor alone or in combination with basal insulin can be used as a treatment for hyperglycemia with patients still in hospital.Hyperglycemia can also be improved through minor lifestyle changes. Increasing aerobic exercise to at least 30 minutes a day causes the body to make better use of accumulated glucose   since the glucose is being converted to energy by the muscles. Calorie 
monitoring, with restriction as necessary, can reduce over-eating, which contributes to hyperglycemia.Diets higher in healthy unsaturated fats and whole wheat carbohydrates such as the Mediterranean diet can help reduce carbohydrate intake to better control hyperglycemia. Diets such as intermittent fasting and ketogenic diet help reduce calorie consumption which could significantly reduce hyperglycemia. Carbohydrates are the main cause for hyperglycemia—non-whole-wheat items should be substituted for whole-wheat items. Although fruits are a part of a complete nutritious diet, fruit intake should be limited due to high sugar content. Epidemiology
Environmental factors
Hyperglycemia is lower in higher income groups since there is access to better education, healthcare and resources. Low-middle income groups are more likely to develop hyperglycemia, due in part to a limited access to education and a reduced availability of healthy food options. Living in warmer climates can reduce hyperglycemia due to increased physical activity while people are less active in colder climates.