Normally, blood glucose levels stay within narrow limits throughout the day: 70 to 120 mg/dL = 3.89 to 6.66 mmol/L. Levels rise after meals and are usually lowest in the morning, before the first meal of the day.
Having too much sugar in the blood for long periods of time can cause serious health problems if it's not treated. Hyperglycemia can cause damage to the vessels that supply blood to vital organs, which can increase the risk of heart disease and stroke, kidney disease, vision problems, and nerve problems in people with diabetes. These problems don't usually show up in kids or teens with diabetes who have had the disease for only a few years. However, these health problems can occur in adulthood in some people with diabetes, particularly if they haven't managed or controlled their diabetes properly. Ask a doctor to give you specific advice on how to keep your blood sugar levels in a healthy range.
There are three energy sources in the body -- glucose, protein and fat.
Glucose provides instant energy that helps muscles to move and chemical reactions to take place.