Blood Glucose
Introduction
Blood glucose, or commonly referred to as blood sugar, is the form of energy circulating in your blood stream. Food is absorbed and metabolized by the organs in your body, by your enzyme and hormonal systems and eventually nourishes your body. Certain foods, such as carbohydrates and smaller parts of protein, are broken down to blood glucose. When you eat, insulin from your pancreas is activated to release glucose from the blood and transport it to the cells of the body to produce energy.
In a normal state, the body can carefully balance the amount of insulin and glucose and thus regulate blood glucose levels. Normal blood glucose levels are: fasting (before eating) 70-99mg/dl and 140mg/dl or fewer two hours after a meal. Normal A1c blood sugar test is 4-6 percent.
This complex regulation of blood glucose goes awry in diabetes. With type 1 diabetes, the pancreas no longer makes insulin, so blood glucose is very high (hyperglycemia) and cannot get into the cells that need fuel. People with type 1 diabetes need an exogenous (outside the body) source of insulin through insulin injections.
With type 2 diabetes, the pancreas makes insulin, but maybe not enough, or the insulin is unable to adequately transport the glucose into body cells. The blood glucose remains higher than normal. Diabetes is a progressive disease, so a combination of diet, exercise, oral and injectable medications can be used to control blood glucose levels.
The goal of diabetes treatment is to normalize the blood glucose levels with diet, exercise and medication. Your doctor may give you specific blood sugar goals based on your particular medical situation. However, there are two different sets of recommendations to guide your clinician. Your doctor may set higher levels goals in an attempt to “step down” your levels gradually, to avoid hypoglycemia episodes. Be sure to know your goals so you can assess your progress in controlling your diabetes.
American Diabetes Association- Blood glucose goals for people with diabetes:
- Before eating (pre-prandial) 70-130mg/dl
- 1-2 hours after eating (peak post-prandial) <180mg/dl
- A1c blood glucose test (3 month blood glucose indicator) <7 percent
American Association of Clinical Endocrinologists – Blood glucose goals for people with diabetes:
- Before eating (pre-prandial) <110mg/dl
- 2 hours after eating (post-prandial) <140mg/dl
- A1c blood glucose test < 6.5 percent
Blood Glucose Targets
Before you were diagnosed with diabetes, you probably did not think about how your body regulated blood glucose. Now, you have to help your body with this process. First, you need to know your target blood glucose levels. Your blood glucose changes in response to food, exercise, sleep, stress, medications, illness, and other factors.
Target Blood Glucose Levels:
- Fasting and before meals – 70-130mg/dl
- 1-2 hours after the start of a meal – <180mg/dl
- Before bed – 110-150mg/dl
- A1C – <7 percent
Your healthcare provider may modify these goals for your unique treatment plan.
Continuous Glucose Monitoring Offers More Information for Your Health
Ever wonder what is happening with your blood glucose between finger sticks? Or, are you getting good readings, only to find your A1C is high? Now there is a way to follow your blood glucose continuously.
A new device, a Continuous Glucose Monitor (CGM), provides real time measurements of your blood glucose (every five minutes) for up to a week. Now you and your doctor can download the data on the computer and track patterns and detect trends in your diabetes control. You can see what really happens to your blood glucose throughout the night, or after meals, or the effect of exercise on your numbers. You can enter information about your medication, and see the real time effect. You and your doctor can then make changes to your diabetes treatment to obtain better control.
How does it work? The CGM is meant to be used for a selected period of time (up to seven days) to collect real time information. You still need to finger stick four times a day to calibrate. A sensor is placed under the skin that transmits the blood glucose measurements of the interstitial fluid by radio waves to the wireless monitor on your belt. An alarm can be set that alerts you to pre-set high and low blood glucose levels. As an added feature for pump users, the blood glucose information can be transmitted to the insulin delivery system and influence doses.
A number of companies now have FDA approval of their CGM. Insurance and Medicare cover the use for a defined period of time with a request from your physician.
Technology is moving closer and closer to the possibility of an artificial pancreas. Read the latest developments on the artificial pancreas here.
Learn more about available Continuous Glucose Monitors in the DiabetesCare.net product directory.
High Morning Blood Sugars
Have you checked your blood glucose before bed and then you find that by morning, your value has gone up? You did not eat all night—what’s up?
There are 2 reasons for this :
The Dawn Phenomenon
In order to start your day, your body gets a wake-up call from your hormones. These growth hormones depress the activity of insulin, so that your blood glucose rises from 4 a.m. to 8 a.m. Also, additional glucose is released from the liver to get your body going. All of this is happening while your evening insulin dose (if you take insulin) is wearing off. If your morning readings are staying continually high, discuss this with your health care team. You may need more medication, need to re-distribute your medication, or use a medication that lowers the release of glucose from the liver. You can also make dietary changes that lower blood glucose before bed, or change your diet at dinner or snack, or reduce your breakfast carbohydrate.
The Somogyi Effect
Named after the doctor who described this, the Somogyi effect is also known as “rebound hyperglycemia.” Your medication may be part of the problem for the high blood glucose in the morning in this case. Your blood sugar may be dropping too low in the middle of the night because of two much insulin or too little an evening snack so your liver releases glucose to correct this, and may overcorrect. Or simply, you did not have enough long-action insulin before bed.
For whatever reason, you and your health care team need to understand what is happening to correct the high morning blood glucose. You may be asked to do a little detective work – check your blood glucose at 2-3 a.m. If your sugar is very low, it is the Somogyi Effect. If your blood glucose is normal or above normal in the middle of the night, the higher reading in the morning could be a result of the dawn effect. Your health care team can help you make appropriate adjustments.
How Does Your Body Naturally Regulate Blood Glucose?
Eating food is how you provide fuel to your body to stay alive. Food is digested by a complex system of organs, hormones and enzymes and eventually becomes the usable energy for your cells called glucose. Your brain and muscles must have a supply of glucose to function.
The body maintains a minimal level of glucose in the blood, about 70 mg/dl, and also regulates surges of glucose, when you eat a meal, to not exceed 140 mg/dl. When you are not eating, your liver has stored glucose, called liver glycogen, readily available to keep your blood levels at a minimum functioning level. Insulin is minimally at work when there is no food, but another hormone called glucagon is responsible for breaking down the glycogen stores. Your muscles also have stored glucose, muscle glycogen that is constantly being burned for energy – more so when you move. This is the “baseline of fuel” that must be maintained to keep alive.
When you eat a meal, and the food is digested, your blood glucose rises. Typically, two hours after a meal is the highest concentration of glucose in the blood. This rise in blood glucose signals the pancreas to release insulin from the beta cells. Insulin makes the glucose available to the cells of the body. From the first bite of food, there is a burst of insulin secreted to control blood sugar rise. Then a steady stream of insulin is released to handle the continued digestion of the meal. Around the clock, a small amount of insulin keeps control over blood glucose. Insulin’s effect is to lower your blood glucose by transporting the glucose into the cells of the body to be burned for energy or stored as fat. Another hormone, called amylin, is released with the insulin and works in the intestinal tract to regulate glucose absorption.
When this complex system of fueling your body malfunctions, you develop diabetes. Managing diabetes is like a balancing act, and the more you understand what you can do, the better control you will have. You now need to take an active role in keeping your blood glucose as close to normal as possible.
What Affects Your Blood Sugar?
Your blood sugar changes throughout the day.
What makes it rise?
- Eating food
- Illness or infection
- Physical or emotional stress
- Too little diabetes medication
- Too little exercise
- Weight gain
- Certain medications
What lowers your blood sugar levels?
- Insulin or diabetes medications
- Exercise
- Weight loss
- Eating smaller portions of food
- Certain medications
Testing your blood glucose throughout the day helps you see how these factors are affecting it.
Food and Blood Glucose
Eating causes glucose in your blood to go up. How much it increases depends on what you eat (such as how many carbohydrates your food contains) and how much you consume.
Depending on the type of carbohydrate you eat, it can take shorter or longer to digest. The time it takes for food to pass through your stomach – “gastric emptying” in medical terms – affects the amount of glucose in your blood at any one time.
The amount of food you eat also plays a large part in your blood glucose levels. Too much food, or too many carbohydrates, can cause high blood glucose. Too little food or carbohydrates can cause low blood sugar.
Also, how much and what you eat affects the need for insulin in your body. The ability for insulin to lower blood sugar plays such a key role that the Food and Drug Administration (FDA) says eating marks the cornerstone of diabetes treatment.
How much and what foods are right?
Many people with diabetes follow an eating plan, but no single plan is right for everyone. Your personal plan will depend on your lifestyle and individual preferences.
The American Diabetes Association recommends that people with diabetes follow these general guidelines:
- Eat carbohydrates from fruits, vegetables, whole grains, legumes and low-fat milk.
- Eat fiber-rich foods.
- Keep saturated fats to less than seven percent of total caloric intake.
- Eat at least two servings of non-fried fish per week.
- Limit trans fats.
- Restrict cholesterol intake to less than 200mg/day.
Remember…You are in charge! Do not become discouraged just because you need to think carefully about your food choices. For example, living with diabetes does not mean you can never eat foods with sugar, however; you do need to make some changes to live as healthy as possible.
