Having too much glucose in the blood stream for long periods of time can cause serious health concerns if it is not remedied as soon as possible. Hyperglycaemia or high blood sugar, can cause health concerns in the blood vessels that supply blood to vital organs, resulting in potential heart and circulation issues, kidney concerns, vision and nerve health challenges. An example of a sample result of a blood sugar level less than 140 mg/dL (7.8 mmol/L), would be considered healthy and normal.