Understanding your blood glucose level

Why do I need to monitor my blood glucose level?

The only way to know if your blood glucose level is within the recommended range is to take s ample of your blood and measure the amount of glucose in it. This is important even if you are eating healthily and being active. Regular tests tell you how your blood glucose level is affected by your food, the amount and type of activity you do, and by the impact of stress and illness. If your blood glucose level is regularly too high you are more likely to develop long-term complications.

What level of blood glucose should I be aiming for?

Blood glucose is measured in milligram per deciliter. The ideal range is 75-130 mg/dl. Even when your blood glucose is well controlled, you are always likely to get occasional results outside this range, but it is the general pattern of your results that is important.

Why can’t I rely on symptoms to tell me whether my blood glucose level is too high or low?

If your blood glucose is slightly raised (between 130 and 180 mg/dl), you probably won’t have symptoms (your body starts producing larger amounts of urine only when your blood glucose is above this level). If you regularly have high readings, you may not get symptoms until your blood glucose level is 270 mg/dl or higher. With a low blood glucose level, it can be dangerous to wait for symptoms, because by that point you may be feeling too confused or disoriented to treat yourself.

What should I do if I keep getting high blood glucose levels?

These levels might be caused by weight gain, eating more, or being less active than usual. If you know that one of these factors is responsible, you may be able to remedy it yourself. If you still have high readings for no obvious reason over a week or two, you may need to alter your medication. Your health professional can help you identify what changes you might need to make to your pills or insulin.

I often get readings below 75 mg/dl but I feel fine. Am I hypoglycemic or not?

Yes, hypoglycemia means any blood glucose level below 75 mg/dl, although the level at which you start to have symptoms may vary. If you have had diabetes for years and have often had hypoglycemic attacks, your body may no longer give you early warning symptoms. Keeping your blood glucose level above 75 mg/dl and taking glucose whenever it drops lower will help restore your early warning symptoms.

I’m taking insulin and sometimes have hypoglycemia and then a very high reading later. Why does this happen?

If you have readings below 75 mg/dl, your body will produce extra glucose to help you recover, which contributes to the high reading a few hours later. Preventing the hypoglycemic attacks, either by reducing your insulin dose or making other changes, will help prevent the high readings that follow.

My uncle has diabetes and tests his urine for glucose. Why have I been taught to test my blood?

Urine testing was once the standard way to monitor diabetes, but it is no longer recommended because it will show a positive result only when your blood glucose is around 180 mg/dl or above. Blood testing is more accurate and up-to-date. Your uncle could discuss with his health professional whether it would be helpful for him to test his blood instead.

How frequently should I check my blood glucose level?

This will depend on what information you need at the time. For example, if your medication has changed or if you are sick, you may need a lot of information and be testing 4-7 times a day. At times when your blood glucose level does not vary much, you might test a lot less frequently than this and, on some days, you may not test at all. Your health professional can help you work out how often you should test. The main reason for testing is to find out what you need to do to keep your blood glucose in the recommended range.

At what times of day should I check my blood glucose?

Testing before a meal tells you what your blood glucose level is when it is least affected by food. Also, testing 2 hours after a meal tells you how well your body has used the glucose from your meal. Testing before you go to bed will tell you whether you need to take any action to keep your blood glucose in the recommended range during the night. Testing at one or more of these times helps you compose a picture of what happens to your blood glucose level at different times of the day and in response to food and medication. You may want to test at other times – for example, if you want to find out the effect of physical activity on your blood glucose level.

In what situations is it really important for me to test?

If you inject insulin or take insulin-stimulating pills, test your blood glucose level if you start to feel hypoglycemic so that you can take action quickly. Test your blood glucose level before you drive and take action if necessary to avoid a hypoglycemia while driving. Testing when you are sick is also important.

When might I need to check my blood glucose level more frequently than usual?

You may want to test more often when your diabetes treatment changes of if you are diagnosed with long-term complications such as kidney or eye problems. There are also short-term situations in which you might need more information about your blood glucose level: for example, when you are ill, when you are drinking alcohol, and when you are in a hot climate. Also, if your weight changes, you become more or less active, or your eating patterns change, testing more often can help you check that your blood glucose level is still in the recommended range. If it isn’t, you can take steps to remedy it before it starts to cause longer-term damage.