Diabetes 911. Larry A. Fox

you take insulin, one of the most concerning times to have a low blood glucose level is during the night, when you are sleeping. Recent research has shown that a good way to help minimize the chance of nighttime hypoglycemia is to make sure your blood glucose is over 100 mg/dl at bedtime. Before going to sleep, check your blood glucose. If it is under 100 mg/dl, take 15–30 grams of carbohydrate. If a bedtime snack is a part of your self-care regimen and your blood glucose level before the snack was under 100 mg/dl, make sure you check after the snack is finished to be sure that the blood glucose level has risen over 100 mg/dl.

      Knowing what your blood glucose level is doing while you are asleep is important. This is especially important for people taking insulin or taking medicines that increase insulin production overnight. We recommend testing blood glucose between bedtime and awakening a couple of times per week, varying the time when the blood glucose check is done. Insulin levels peak at different times; knowing when these peaks occur helps you know the best times to test blood glucose levels. Knowing your blood glucose pattern during your sleep time will guide you in deciding whether any insulin or medicine changes need to be made before low blood glucose levels occur. This will help prevent hypoglycemia (and high blood glucose levels) during sleep hours.

      Insulin and Exercise

      The important role of exercise in managing diabetes cannot be overemphasized, but with the benefits come the risk of hypoglycemia. Regular exercise improves the way insulin works in the body and helps you maintain a healthy weight. Exercise also allows the body to use sugar faster, decreasing how much insulin is needed. Thus, exercise can cause hypoglycemia because there is a high amount of insulin in your system relative to the amount of glucose from the liver or from the food you ate. Exercise continues to improve how your body uses glucose, even after you stop exercising. The more frequently and more intensely you exercise, the longer the effects of exercise can last (as long as 24 hours after the activity is over). Therefore, if you are exercising, you may need to take less insulin than usual for up to the next 24 hours.

       RECOMMENDATIONS FOR PREVENTING EXERCISE-RELATED HYPOGLYCEMIA

      The following recommendations will help minimize the chances of experiencing hypoglycemia related to exercise.

      

Check your blood glucose before exercising and every 30–60 minutes during the activity, depending on the intensity of the exercise.

      

You may have to take 15–30 grams of carbohydrate before exercise, depending on your blood glucose level before exercise and the intensity of the exercise you plan to undertake. Experience will tell you what blood glucose levels work best for you before a particular activity. Some people want their blood glucose to be over 100 mg/dl, some over 120 mg/dl, and others over 180 mg/dl before exercising. One recent study in children, however, showed that having a blood glucose level over 130 mg/dl before exercise decreased the chance of experiencing hypoglycemia during exercise. This study was done in children on insulin pumps, so these results may not apply to everyone. Nonetheless, try using 130 mg/dl as a starting level, and if you are below that level, take some extra carbohydrate before exercise. Be sure to talk to your diabetes team for guidance.

      

Make sure sources of carbohydrate (such as a juice box or glucose tablets or gel) and a glucagon kit are available at all times, including when you are exercising.

      

Be sure to check your blood glucose during the activity period. During exercise, if your blood glucose begins to dip below your cutoff point—or if it seems to be dropping quickly—take 15–30 grams of carbohydrate. Recheck your blood glucose level 15 minutes later to be sure it has not dropped further.

      

Insulin dose changes may be required during the activity and possibly even later, because the effects of exercise on insulin needs can last up to 24 hours.

      

If you use an insulin pump, changes in your basal rates may be required. Many people disconnect their pump before starting exercise. Some research has shown that hypoglycemia is much less likely during exercise if the basal rate is stopped. However, we recommend not being disconnected from your insulin pump for more than two hours at a time because this may leave the body without insulin for too long. You can also decrease your basal rate through your insulin pump using the temporary basal rate features. Talk to your diabetes team about changes to your insulin pump regimen during and after exercise.

      Knowing your needs and your response to exercise is critical. Different exercise routines, regimens, or even times of day can give very different responses. The key is to be proactive and learn your patterns by monitoring, reviewing, and adjusting to your needs.

      As a reminder, the effects of exercise on insulin needs can last up to 24 hours after the exercise is over. Because of this, it is not uncommon to experience hypoglycemia in the middle of the night after a day of activity. This is obviously a time when lows need to be prevented. Be sure to check blood glucose levels frequently after exercising, including during late night or early morning hours.

Alcohol

      Several precautions need to be taken when it comes to having diabetes and drinking alcohol (see RECOMMENDATIONS FOR PREVENTING ALCOHOL-RELATED HYPOGLYCEMIA). Alcoholic beverages can contain carbohydrate and may cause blood glucose levels to initially rise. However, alcohol impairs the body’s response to low or decreasing blood glucose levels. This effect can be quite delayed, up to 12 hours after drinking. Additionally, alcohol impairs judgment, so your ability to recognize and treat hypoglycemia will be reduced. When slightly intoxicated or drunk your ability to think straight is altered; you may not recognize hypoglycemia when it happens and may not treat it properly even if you do. Alcohol is metabolized (broken down) by the liver, and during this process, the liver does not make as much glucose as normal. Thus, alcohol impairs one of the body’s key responses to low blood glucose—releasing stored glucose from the liver to raise blood glucose levels.