Glucose is vital to your health because it's an important source of energy for the cells that make up your muscles and tissues. It's also your brain's main source of fuel. If you have diabetes, no matter what type, it means you have too much glucose in your blood, although the causes may differ. Too much glucose can lead to serious health problems.
Insulin is a hormone made by your pancreas that acts like a key to let blood sugar into the cells in your body for use as energy. If you have type 2 diabetes, cells don’t respond normally to insulin; this is called insulin resistance. Your pancreas makes more insulin to try to get cells to respond. Eventually your pancreas can’t keep up, and your blood sugar rises, setting the stage for prediabetes and type 2 diabetes. High blood sugar is damaging to the body and can cause other serious health problems, such as heart disease, vision loss, and kidney disease.
Lose Weight: If you are overweight, losing weight can help your body use insulin. In fact, the American Diabetes Association recommends that people with diabetes lose about 7 percent of their body weight, which should improve the way your body uses insulin and reduces insulin resistance. In addition, weight loss can help lower blood pressure, reduce joint pain, increase energy, and reduce sleep apnea and cholesterol. It can also reduce your risk of other diseases, including heart disease.
With such a surplus of food nowadays, it's easy to overindulge without physical activity, leading to weight gain and, for some people, eventual Type 2 diabetes. "It's a lack of exercise and still eating like you're 20 years old," says Susan M. De Abate, a nurse and certified diabetes educator and team coordinator of the diabetes education program at Sentara Virginia Beach General Hospital.
History of diabetes: Past treatments and new discoveries Diabetes has been known for at least 2,000 years. Over the years, treatments have included exercise, riding on horseback, drinking wine, consuming milk or rice, opium, and overfeeding. It was not until 1921 that insulin was introduced as a treatment. Science has progressed, but diabetes remains a major health problem. Read now
WELL-CONTROLLED DIABETES MELLITUS: Daily blood sugar abstracted from the records of a patient whose DM is well controlled (hemoglobin A1c=6.4). The average capillary blood glucose level is 104 mg/dL, and the standard deviation is 19. Sixty-five percent of the readings are between 90 and 140 mg/dL; the lowest blood sugar is 67 mg/dL (on April 15) and the highest is about 190 (on March 21).
In type 1 diabetes (formerly called insulin-dependent diabetes or juvenile-onset diabetes), the body's immune system attacks the insulin-producing cells of the pancreas, and more than 90% of them are permanently destroyed. The pancreas, therefore, produces little or no insulin. Only about 5 to 10% of all people with diabetes have type 1 disease. Most people who have type 1 diabetes develop the disease before age 30, although it can develop later in life.
To diagnose diabetes, doctors will take a medical history (ask you about symptoms) and ask for blood and urine samples. Finding protein and sugar in the urine are signs of type 2 diabetes. Increased glucose and triglyceride (a type of lipid or fat) levels in the blood are also common findings. In most cases, blood glucose levels are checked after a person has been fasting for 8 hours.
Type 1 diabetes mellitus is predominantly a disease of the young, usually developing before 20 years of age. Overall, type I DM makes up approximately 15% of all cases of diabetes. It develops in approximately 1 in 600 children and is one of the most common chronic diseases in children. The incidence is relatively low for children under the age of 5, increases between 5 and 15, and then tapers off.
Autonomic changes involving cardiovascular control (eg, heart rate, postural responses) have been described in as many as 40% of children with diabetes. Cardiovascular control changes become more likely with increasing duration and worsening control.  In a study by 253 patients with type 1 diabetes (mean age at baseline 14.4 y), Cho et al reported that the prevalence of cardiac autonomic dysfunction increases in association with higher body mass index and central adiposity. 
Prediabetes is a condition in which blood glucose levels are too high to be considered normal but not high enough to be labeled diabetes. People have prediabetes if their fasting blood glucose level is between 100 mg/dL and 125 mg/dL or if their blood glucose level 2 hours after a glucose tolerance test is between 140 mg/dL and 199 mg/dL. Prediabetes carries a higher risk of future diabetes as well as heart disease. Decreasing body weight by 5 to 10% through diet and exercise can significantly reduce the risk of developing future diabetes.
Diabetes mellitus type 2 is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. This is in contrast to diabetes mellitus type 1 in which there is an absolute insulin deficiency due to destruction of islet cells in the pancreas and gestational diabetes mellitus that is a new onset of high blood sugars associated with pregnancy. Type 1 and type 2 diabetes can typically be distinguished based on the presenting circumstances. If the diagnosis is in doubt antibody testing may be useful to confirm type 1 diabetes and C-peptide levels may be useful to confirm type 2 diabetes, with C-peptide levels normal or high in type 2 diabetes, but low in type 1 diabetes.
Diabetes may have symptoms in some people, and no symptoms in others. Generally, people with Type 1 diabetes have increased thirst (polydipsia), frequent urination (polyuria), and increased hunger (polyphagia). Symptoms may develop over weeks to months. Untreated, this condition may cause a person to lose consciousness and become very ill (diabetic ketoacidosis).
When your blood sugar is out of whack, you just don’t feel well, says Cypress, and might become more short-tempered. In fact, high blood sugar can mimic depression-like symptoms. “You feel very tired, you don’t feel like doing anything, you don’t want to go out, you just want to sleep,” Cypress says. She’ll see patients who think they need to be treated for depression, but then experience mood improvement after their blood sugar normalizes.
There are some interesting developments in blood glucose monitoring including continuous glucose sensors. The new continuous glucose sensor systems involve an implantable cannula placed just under the skin in the abdomen or in the arm. This cannula allows for frequent sampling of blood glucose levels. Attached to this is a transmitter that sends the data to a pager-like device. This device has a visual screen that allows the wearer to see, not only the current glucose reading, but also the graphic trends. In some devices, the rate of change of blood sugar is also shown. There are alarms for low and high sugar levels. Certain models will alarm if the rate of change indicates the wearer is at risk for dropping or rising blood glucose too rapidly. One version is specifically designed to interface with their insulin pumps. In most cases the patient still must manually approve any insulin dose (the pump cannot blindly respond to the glucose information it receives, it can only give a calculated suggestion as to whether the wearer should give insulin, and if so, how much). However, in 2013 the US FDA approved the first artificial pancreas type device, meaning an implanted sensor and pump combination that stops insulin delivery when glucose levels reach a certain low point. All of these devices need to be correlated to fingersticks measurements for a few hours before they can function independently. The devices can then provide readings for 3 to 5 days.