• High blood sugar may not cause an immediate emergency but may lead to severe complications over time. People with a history of chronic high blood glucose can develop debilitating eye disease, kidney disease, circulation problems, or nerve disease. They can also be at risk for dehydration.
How Often You Should Monitor
Of course, how often you monitor your blood glucose is highly individual. It depends on: whether you have type 1 or type 2 diabetes, your blood glucose goals, how often you’re willing to prick your finger, and what supplies you can afford. How often you monitor also depends on your reasons for checking your blood glucose.
If you have type 1 or type 2 diabetes and you use the results to adjust your next insulin injection or food intake, then you may need to check your blood glucose level each time before you inject or eat a meal (3–4 times a day). You might also monitor after meals to see if you gave the right insulin dose.
If you aim for a blood glucose level close to normal, it’s essential to monitor at least four, and sometimes eight, times a day. You would check before and after each meal and before bedtime every day and in the middle of the night (around 3 a.m.) about once a week. Studies in type 1 diabetes have shown a relationship between the number of blood checks a day and blood glucose control. You’ll hear more about setting goals for keeping your blood glucose levels as close to normal in chapter 9.
However, you may only be taking one or two insulin shots each day or oral medications, so you may decide to monitor just two times each day. Blood glucose levels in people with type 2 diabetes are often more stable over the course of a day. If you take oral diabetes medications, you may not need to monitor as often because you can’t use the results to fine-tune your dose.
People with type 2 diabetes who manage their blood glucose without medications might monitor once or twice a day, three or four times a week, or not at all. However, checking your blood glucose levels regularly will help you keep track of your diabetes and see how all of your efforts are working. One approach is to routinely measure your fasting or pre-breakfast blood glucose levels. It can also help to check your blood glucose at different times of the day: before and after exercise, before and after meals, and at bedtime. This gives you a better idea of what is happening with your blood glucose levels.
Monitoring Goals
Your goal is to understand the pattern of your blood glucose in response to your daily lifestyle. However, you may also need to capture unusual highs and lows.
Standard Times to Check Blood Glucose
• Before breakfast, lunch, dinner, or an especially big snack
• Before you go to bed
• 1–2 hours after breakfast, lunch, dinner, or an especially big snack
• At 2 or 3 a.m.
Sometimes you may not feel quite right, and you may not know why. Monitoring your blood glucose may help you pinpoint the problem. For example, if you feel sweaty and a little shaky after a three-mile run, you may just be tired from the workout or you could be having a low blood glucose reaction. You simply don’t know without monitoring. You may decide to eat because you think your blood glucose is low, but it could actually be high. Only monitoring will give you the information you need to make the right decision about treatment.
Over time, you will gain confidence in your ability to manage your diabetes. You may think it’s okay to monitor less often. Beware! It’s tempting to think you can tell what your glucose level is by the way you feel, but research shows that most people cannot guess their glucose levels reliably. Guessing is dangerous, especially if your blood glucose level tends to swing with little warning.
When to Do Extra Checks
There are times when you’ll need to monitor your blood glucose more often, particularly when you’re trying to decipher how new situations affect your blood glucose. In general, changes in medication, food, physical activity, stress, and illness will affect your blood glucose. So, you’ll need to perform extra blood glucose checks during these situations. These checks will help you respond to and treat your blood glucose properly. Remember, you should always monitor your blood glucose when you suspect that it is too high or too low.
Extra Checks for Meals
Put most simply, some foods make your blood glucose go up. However, there are quite a few nuances to keep in mind. The amount and type of carbohydrates in certain foods, as well as the amount of food you eat during a meal, will affect your blood glucose level. Sounds complicated, right?
Well, the best way to take charge is to begin to learn how the food you eat affects your blood glucose levels. You’ll want to monitor your blood glucose more closely when you eat new foods or eat special meals. You may be surprised at how your glucose level responds to different foods. Measure your blood glucose 1–2 hours after you eat particular foods. Do you find that your blood glucose rises faster after you eat rice or pasta? Does it rise faster after a cookie or a granola bar? By figuring out how your body responds to specific foods, you can have a plan so that your blood glucose will not rise too high, too fast. You can read more about managing your diabetes and food in chapter 10.
Extra Checks for Physical Activity and Exercise
In general, physical activity, including exercise, will lower your glucose and make your body more sensitive to insulin. During exercise, your muscles work harder and use up the glucose they have stored for fuel. Your body uses glucose from the blood when the glucose stored in muscles becomes low. Exercise can help use up some of the glucose that builds up in the blood.
You need to take special precautions when you exercise. You want to make sure that your blood glucose levels don’t drop too low too fast. This can happen in the hours after exercise when your muscles take glucose from the blood to restore their glucose reserves (this is more common in type 1 diabetes). Make sure to check your blood glucose immediately after exercising as well as several hours later.
Doing extra checks before and after physical activity will help you decide if you need to eat a little more or inject a little less insulin. Some people with type 2 diabetes find that they no longer have to take insulin or other diabetes medications once they start a regular exercise program. However, to be safe, talk over your blood glucose readings and exercise program with your health care team before you make changes to your diet, insulin, or other medications. Read more about managing your diabetes and physical activity in chapter 11.
High Blood Glucose and Exercise
It sounds strange, but people with type 1 diabetes will also need to check their blood glucose to make sure that it isn’t too high during exercise. If your blood glucose level is over 250 mg/dl, exercise may cause your blood glucose level to go up rather than down.
Hard exercise with too little insulin can make the liver release stored glucose. Someone with type 1 diabetes whose blood glucose is greater than 250 mg/dl should test for ketones (read about how to test for ketones in chapter 7). Do not exercise if ketones are present. Use caution if your blood glucose is greater than 300 mg/dl, even if no ketones are present.
Extra Checks for New Medications or Insulin
If you have type 2 diabetes and take oral medication, finding the best dose can be tricky. You will need to monitor frequently when you are starting a new medication or trying to find the best dose of medication. Check your blood glucose once or twice a day (before breakfast and one other time during the day) to avoid low blood glucose. Occasionally you may want to check 2 hours after meals to see how well the medication works with your meal plan. Your monitoring records will help you and your health care provider decide what changes, if any, are needed.
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