High Sugar (Glucose) Levels in Blood or Urine – What does it mean?

How does sugar get into the blood?

All food that is digested and then absorbed travels through the bloodstream to the liver. Here it is processed further – some is broken down into simpler compounds, some is stored and others may be converted or even excreted. However, the body retains almost all of the macronutrients – carbohydrates, proteins and fats – in some form or the other. The cells in the body need a constant supply of nutrients to produce energy. This is mainly in the form of glucose, a type of simple sugar.

Carbohydrates are the main source of energy in that it is broken down into simple sugars like glucose and then transported via the bloodstream to all the cells of the body for energy production. When carbohydrates are in short supply, the body will use proteins or fats which can also be converted into glucose. Sugar in the blood is therefore derived from :

  • nutrients absorbed from the gut and on its way to the liver
  • food broken down by the liver and glucose released to the body’s cells
  • conversion of fats or protein into glucose for energy production when carbohydrates are in short supply

How is blood sugar controlled?

Glucose can damage the cells in the body if the levels are not kept within a specific range. However, if these levels drop too low then it compromises energy production and normal cell activity. The body has to therefore ensure that the blood glucose levels are neither to high nor too low. Often the concern focuses more around elevated blood glucose levels (hyperglycemia) which occurs in diabetes mellitus (sugar diabetes). This condition is on the rise globally and has a wide range of effects on different organs with at times fatal consequences.


Glucose regulation is achieved mainly by two hormones – insulin and glucagon. Both these hormones are secreted by the pancreas. There are several other hormones and physiological processes in the body that can also impact on blood glucose levels but not to the extent as insulin and glucagon. Simply, insulin lowers blood glucose levels when it is too high. Glucagon on the other hand raise the blood glucose levels when it is too low. This is done through several of the effects that these hormones have on almost every cell in the body.


The other way to control blood sugar levels is through :

  • diet – quantity of food, type of carbohydrates in food and frequency of meals
  • exercise – regular cardiovascular activity
  • medication – drugs for hyperglycemia (high blood glucose levels) and hypoglycemia (low blood glucose levels)


Body weight also impacts on the blood glucose levels and it is modifiable meaning that a person can change their body weight through diet and exercise. A higher body weight not only increases the risk of diabetes mellitus, a condition marked by abnormally high glucose levels, but also negatively affects the glucose control in a person of normal tolerance or with diabetes.

What does high sugar levels mean?

High blood sugar levels means that the body is unable to keep the glucose levels within a normal range. It indicates a problem primarily with the insulin levels that are secreted in response to the blood sugar levels. When the blood sugar (glucose) is too high, the pancreas secretes more insulin which then helps to lower the blood glucose levels to some degree thereby bringing it within a normal range. In conditions such as diabetes mellitus, there is either a deficiency of insulin or resistance to the effects of insulin. This means that the body cannot adequately deal with the elevated blood sugar levels. Therefore the sugar levels remain high.

Blood Sugar Levels

It is important to know the normal reference range of the blood sugar levels. This is the range where the body is supposed to maintain the blood sugar levels at all times – whether upon waking, before and after eating, during sleep and the course of the day irrespective of physical activity or eating habits. There are certain times when the sugar levels are higher or lower but still within the normal range.

  • Fasting glucose are those levels upon waking – essentially having not eaten for at least 8 hours.
  • Pre-prandial glucose levels are the levels before eating a meal. It can vary during the course of a day. Therefore only the breakfast pre-prandial level is taken into consideration since it is the same as the fasting glucose level.
  • Post-prandial glucose levels are the levels after eating. Usually the 2 hour level is recorded although in pregnant women, the 1 hour and 3 hour post-prandial levels are also significant for testing.

Normal blood sugar levels

  • Fasting = 70 to 99 mg/dL (3.9 to 5.5 mmol/L)
  • Post-prandial (1 hour) = 120 to 140 mg/dL (6.6 to 7.8 mmol/L)
  • Post-prandial (2 hour) = 70 to 99 mg/dL (3.9 to 5.5 mmol/L)

Pre-diabetes blood sugar levels

Pre-diabetes or impaired glucose tolerance (IGT) is the stage of abnormal blood glucose regulation before diabetes mellitus develops. It can last for months or even years before the onset of diabetes mellitus and pre-diabetes is reversible.

  • Fasting = less than 125mg/dL (6.9 mmol/L)
  • Post-prandial = 140 to 200 mg/dL (7.8 to 11.1 mmol/L)

Diabetes blood sugar levels

  • Fasting = 70 to 140 mg/dL (3.9 to 7.8 mmol/L)
  • Post-prandial = exceed 200 mg/dL (11.1 mmol/L)

Urine Sugar Levels

The kidney filters blood to form urine. Normally glucose is not found in the urine. When the blood glucose levels are elevated, glucose passes into the urine. This is known as glucosuria or glycosuria. However, in rare instances glucose can be passed into the urine from the kidney tissue despite the blood glucose levels being within the normal range – renal glycosuria.

Normal urine glucose levels are between o to 15 mg/dL (0 to 0.8 mmol/L).

Treating High Sugar Levels

Whether high sugar levels are found in the blood, urine or even CSF (cerebrospinal fluid), it needs to be treated and managed. This can be achieved with :

  • Eating low GI, low fat and low calorie foods.
  • Exercising for at least 150 minutes in a week – 30 minutes per day.
  • Losing weight to return to a normal BMI (body mass index) or at least 5% to 10% of total body weight.
  • Using oral antidiabetic medication like metformin.
  • Administering exogenous insulin.

High blood sugar levels that exceed 200 mg/dL (11.1 mmol/L) at anytime is indicative of diabetes mellitus. This is a chronic condition which requires proper treatment and management by a medical professional. Medication is usually necessary and this is often for life since the condition is largely irreversible. Pre-diabetes on the other hand can be reversed by eating right, exercising and losing weight. Although seen as a ‘milder’ condition, pre-diabetes needs to be monitored regularly by a health care professional to ensure that the diet and lifestyle measures are yielding the desired results.

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