Think Like a Pancreas

by Gary Scheiner

  If your blood sugar drops low for the first twenty-four hours after your period begins, reduce your basal insulin dose or cut back on your meal boluses by 20 to 30 percent.

  Travel

  Travel can present special challenges for people with diabetes. Due to changes in meals, activity, and schedules, blood sugars may vary quite a bit when you travel. Time zone changes can wreak havoc on control because your normal basal insulin patterns may not match your sleep/wake schedule at your destination. When in transit, your blood sugar levels may run higher than usual. This is caused by a combination of factors, including the stress of travel, consumption of restaurant meals, and the fact that prolonged sitting tends to diminish sensitivity to insulin. However, the pattern can change dramatically when you arrive at a vacation destination. The sudden decrease in stress, extra walking, new surroundings to absorb mentally, and (perhaps) warmer temperatures can lead to an overall drop in blood sugar levels.

  The Adjustment: Plan to take a little extra basal insulin on travel days but a little less once you arrive and settle in at your destination. Incidentally, if you need to take an insulin injection on a plane using vials and syringes, only inject half as much air as usual into the vial. Cabin pressure is a bit lower than the air pressure on the ground, so you won’t need to build up as much pressure inside the vial.

  When traveling across time zones, you may need to make some insulin program adjustments. If you use an insulin pump, simply adjust the clock on the pump to correspond with the local time once you arrive. This will help ensure that the peaks and valleys in your basal insulin program will correspond to your sleep schedule at your destination.

  Those taking glargine, levemir, or NPH should continue to take the injections twenty-four hours apart. This may mean changing the time of your injection. For example, if you normally take your glargine at 10 p.m. and travel west across three time zones, you should begin taking it at 7 p.m. (local time) once at your destination. Upon traveling home, you can resume your usual injection time of 10 p.m.

  Be aware that insulin outside the United States could have a different concentration than the U-100 insulin you are used to using. U-40 insulin is common in some countries, which means that the insulin is only 40 percent as potent as U-100 insulin. If you run out of your insulin and are forced to use U-40 insulin, multiply your usual dose by 2.5. In other words, if you usually take 10 units of U-100 insulin, you will need 25 units of U-40 to get the same effect. If using a pump with U-40 insulin, increase your bolus doses and your basal rates by 250 percent (multiply your usual doses by 2.5).

  And remember, insulin is stable at room temperature for up to a month. There is not usually a need to refrigerate your insulin while traveling. However, if the temperature at your destination is in excess of 90 degrees Fahrenheit and your accommodations are not air conditioned, either store your insulin in a refrigerator or bring along a temperature-controlled case for your insulin vials and pens. (See Chapter 10 for travel case options.)

  Irregular Sleep

  Sleeping isn’t just something we do to pass the time at night and during afternoon history classes. Sleep is also a powerful regulator of appetite, energy use, and weight. Lack of sleep can cause an increase in stress hormone production and may cause a rise in blood sugar levels. It also tends to increase appetite and can lead to insulin resistance and weight gain, particularly when normal sleep hours are spent in a sedentary state (watching TV, etc). Conversely, if normal sleep hours are spent working or engaging in physical activity, blood sugars can run lower than usual.

  The Adjustment: Be prepared to increase your basal and bolus insulin doses if you are having difficulty sleeping—particularly if you are sleeping less than six hours per night. However, if you are forced (or choose) to work late into the night, you may need to reduce basal insulin temporarily by 20 to 40 percent or have periodic snacks to prevent hypoglycemia.

  Just about everyone benefits from maintaining a fairly consistent sleep/wake schedule. If you are having difficulty maintaining a normal sleep pattern, you may benefit from avoiding caffeine, naps, and nighttime exercise (although daytime exercise can be beneficial). Having a comfortable sleep area that you only use for sleeping and engaging in a relaxing activity thirty minutes prior to bedtime are also helpful. In some cases, you can attribute sleep disturbances to emotional upset or an underlying illness. If this is the case, your physician may be able to prescribe appropriate medication or refer you for counseling.

  Menopause

  Natural menopause is caused by the ovaries progressively reducing estrogen production. Surgical menopause occurs when the ovaries are removed, resulting in a sudden decrease in estrogen. Weight gain often accompanies menopause. Hot flashes, mood swings, and fatigue may occur as levels of estrogen ebb and flow. Because estrogen makes the body more sensitive to insulin, blood sugar control during menopause can become more challenging.

  The Adjustment: Many women report more frequent and severe low blood sugars during early menopause, especially during the night. Most find that in the later stages, as estrogen levels decrease permanently, their bodies are more resistant to insulin and that they require higher insulin doses. However, changes in blood sugar levels during menopause are varied and highly individualized. I would hesitate to make permanent changes to your program until a pattern of high or low readings is established over a period of several consecutive days.

  Daily fluctuations in estrogen levels are common and can fool you into thinking that you need to make a change in your overall program. Try not to let the seemingly senseless blood sugar variations frustrate you—it is a common and natural occurrence during this phase of your life, but one that should resolve on its own over time.

  Symlin (pramlintide)

  As presented back in Chapter 3, Symlin is an injectable replacement for the amylin hormone that the beta cells of the pancreas normally secrete (along with insulin). One of Symlin’s primary functions is to slow the emptying of the stomach’s contents into the small intestine, where the carbs and other nutrients are then absorbed into the blood stream. When taken along with rapid-acting insulin, Symlin can sometimes cause blood sugar levels to drop soon after eating and then rise a few hours later.

  The Adjustment: Although you may not need to alter the amount of bolus insulin much (the average bolus reduction is only 10 to 20 percent) when you take Symlin, you will certainly need to alter the timing. For those taking injections, I advise you to either take the mealtime rapid-acting insulin after eating or switch to regular insulin. For those using an insulin pump, extending the bolus over one to two hours will provide a better match to the delayed blood sugar rise.

  Sports and Exercise

  As discussed in the previous chapter, the blood sugar commonly drops during exercise. However, experiencing a blood sugar rise at the onset of high-intensity/short-duration exercise and competitive sports is also common. This is caused by a surge of adrenaline that counteracts the effects of insulin and stimulates the liver to release extra sugar into the bloodstream. That’s why a two-hour soccer practice can produce much lower blood sugars than a competitive two-hour soccer game—even when the same amount of exercise is performed.

  Exercises that often produce a short-term blood sugar rise include:

  •weight lifting, particularly when using high weight and low reps;

  •sports that involve intermittent bursts of activity, like baseball or golf;

  •sprints in events such as running, swimming, rowing, and skating;

  •events in which performance is being judged, such as gymnastics or figure skating; and

  •sporting events in which winning is the primary objective.

  Ironically, the same high-intensity, strenuous sports that produce a short-term blood sugar rise can also produce a delayed blood sugar drop several hours after the activity (as was discussed earlier in this chapter).

  The Adjustment: Given that sports performance hinges on having adequate control of one’s blood sug
ar, it is essential that everyone who exercises or competes makes sound adjustments.

  I discussed prevention of hypoglycemia through mealtime insulin adjustment in detail in Chapter 7. When you are going to perform aerobic/cardiovascular exercise after a meal, reducing the mealtime rapid-acting insulin is almost always in order.

  For Long-Duration Activity

  With prolonged exercise (physical activity lasting more than ninety minutes), reducing your basal insulin can be helpful. This is easy to do with an insulin pump: Simply set a temporary basal rate (50 percent of the usual rate is a good place to start) beginning an hour or two before the activity. Setting the temporary basal rate ahead of time ensures that you will have less basal insulin working at the time your activity begins. If you wait until the activity starts to reduce your basal rate, you will have to wait a couple hours to see a noticeable reduction in the level of insulin in your bloodstream. It is important to note that temporary basal reductions (or suspending the pump or disconnecting) are not of much use for preventing lows with activities lasting an hour or less. Basal changes take an hour or two to start having an effect, and the total amount of the insulin being reduced by a temp basal will not be nearly enough to ward off hypoglycemia.

  Temporary basal reductions are not of much use for activities lasting an hour or less.

  If you take injections, a reduction in your long-acting insulin dose means that you will be lowering your basal insulin level for nearly twenty-four hours—not just during the time you are exercising. However, this can be useful if your activity is lasting throughout most of the day because you will probably need less basal insulin at night as well. In this case, a 25 percent reduction in your injected basal insulin dose prior to the activity is a good starting point.

  With long, intense forms of exercise, preventing hypoglycemia will almost always require a reduction in basal insulin as well as carbohydratecontaining snacks at regular intervals.

  Snacking to Prevent Low Blood Sugar

  Under certain conditions you will need to eat extra food to prevent hypoglycemia during exercise. For example, when exercise is going to be performed before or between meals, reducing the insulin at the previous meal would only serve to drive the preworkout blood sugar very high. A better approach is to take the normal insulin dose at the previous meal and then snack prior to exercising.

  If you decide to exercise soon after you have already taken your usual insulin/medication, snacking will be your only option for preventing hypoglycemia. Also, during very long-duration endurance activities, you may need to eat hourly or half-hourly snacks in addition to reducing insulin/medication.

  The best types of carbohydrates for preventing hypoglycemia during exercise are ones that digest quickly and easily (high-glycemic-index foods). These include sugared beverages (including juices, soft drinks, and sports drinks), bread, crackers, cereal, and low-fat candy.

  The size of the snack depends on the duration and intensity of your workout. The harder and longer your muscles are working, the more carbohydrate you will need. The amount is also based on your body size: The bigger you are, the more fuel you will burn while exercising, and thus the more carbohydrate you will need.

  Granted, there is no way of knowing exactly how much you will need, but the figures in Table 8-2 should serve as a reasonable starting point. To use the chart, line up your approximate body weight with the intensity of the exercise. The grams of carbohydrate represent the amount that you will need prior to each hour of activity. If you will be exercising for half an hour, take half the amount indicated. If you will be exercising for two hours, take the full amount at the beginning of each hour. Of course, if your blood sugar is elevated prior to exercising, you will need fewer carbs; if you are below target, you will need additional carbs.

  Table 8-2. Carbs to maintain blood sugar during exercise

  For example, if you weigh 150 pounds (68 kg) and plan a moderateintensity, forty-five-minute workout, try taking about 25 grams of carb beforehand. If your preworkout blood sugar is elevated, cut back to 10 to 15 grams. If your blood sugar is below target, increase to 35 to 40 grams.

  For those who use insulin pumps and choose to lower the basal insulin prior to and during physical activity, the amount of carbohydrate you will need (or the frequency with which you need to eat) will be reduced.

  For a more detailed look the carbohydrate required for a variety of different activities, see the “Carb Replacement” chart in Appendix D.

  Preventing Blood Sugar Rises During Sports

  If you notice that your blood sugar rises during certain types of activities, taking extra insulin beforehand is in your best interest. Case in point: One of my teenage clients always saw his blood sugar drop steadily during hockey practice, though games caused just the opposite effect; his blood sugar would rise well into the 300s (17–22 mmol/l) when he played competitively. When he started taking extra insulin before games, his blood sugar stayed closer to normal, and his speed, stamina, and mental focus all went up a notch. In his first tournament trying this approach, he won his first-ever MVP trophy!

  To prevent a blood sugar rise during sports activity, take a small dose of insulin beforehand.

  To determine how much insulin to take before a high-adrenaline form of exercise, consider how much your blood sugar normally rises during the course of an event. If it rises 200 mg/dl (11.2 mmol/l) and your sensitivity factor is 50 (2.8) points per unit, you would normally need to give 4 units of insulin thirty to sixty minutes beforehand. Likewise, if you normally rise 70 mg/dl (3.9 mmol/l) and your sensitivity factor is 30, you will need a little more than 2 units beforehand. However, if you give these full amounts and then start to exercise, you’ll probably wind up sucking glucose gel through a straw before too long. My advice is to take half of the amount you would usually need to offset the expected blood sugar rise. Likewise, if your blood sugar is elevated prior to an athletic event, give yourself half of your usual correction bolus.

  For example, consider our hockey player, Marvin. When Marvin has a game, his blood sugar tends to go up about 150 mg/dl (8.3 mmol/l). His correction factor is 30 mg/dl (1.7 mmol/l) per unit. If his blood sugar before heading for the rink is 200 (11 mmol/l), he needs 2.5 to offset the expected rise (half the 5 units he would normally need) plus 1.5 units to cover his current blood sugar (half the 3 units he would normally take), for a total of 4 units.

  If you are nervous about giving insulin before exercise, check your blood sugar more often than usual (perhaps every half hour) and have glucose tablets or some other form of fast-acting carbohydrate nearby. Given the conservative nature of the dosing, your blood sugar is not likely to drop too low. And if it does, fixing a low is much easier than fixing a high during a sport.

  Pregnancy

  If you have type 1 diabetes, expect your insulin needs to change dramatically through the course of your pregnancy. The proportion of basal (background) to bolus (mealtime) insulin does not change much, but the total amount of insulin required goes through a complete metamorphosis. Do the doses simply rise or fall steadily throughout pregnancy? Of course not! This is diabetes we’re talking about—nothing is simple.

  For most women insulin needs during pregnancy follow a pattern similar to a log flume ride found at an amusement park (see Figure 8-4). Let me explain.

  Figure 8-4. Typical insulin requirements through pregnancy

  Weeks zero to six: Business as usual. You’re just waiting in line to get on the log flume ride, totally oblivious to what you’re in for. You probably don’t even know you’re pregnant, and insulin needs are no different than what they were before you conceived.

  Weeks six to twelve: The slight dip. In log flume terms, this is like when you first get into the log boat and the added weight makes it sink slightly into the water. This is truly an amazing phase: You’ve just found out that you’re pregnant, and you’re quite excited. As the embryo evolves into a fetus, the autoimmune process that has been destroying your beta cells all th
ese years starts to ease up. This allows your pancreas to start secreting some insulin on its own. The result: a reduction in the need for exogenous (pumped or injected) insulin. Low blood sugar is common during this phase, as many women are taken by surprise that they are producing some of their own insulin again. Severe hypoglycemia is three times more common during the first trimester of pregnancy than during the four months preceding pregnancy.

  Weeks twelve to thirty-six: The steady climb. This is the part of the log flume ride when you get on that long, slow conveyer belt up to the top. You know what happens to your body and the baby during this phase: growth, growth, and more growth. Well, the same thing happens to your insulin needs, despite the fact that your pancreas continues to produce small amounts of insulin. This is due to the increase in your body size as well as the hormones the placenta is producing (including human placental lactogen, progesterone, prolactin, and cortisol), which cause insulin resistance. Total daily insulin needs commonly double or triple during the second and third trimesters of pregnancy.

  Weeks thirty-six to delivery: The moment of calm. Once the conveyer belt has brought you to the top, there is always that relaxing, scenic ride before the big plunge. For a few weeks prior to delivery, insulin requirements level off. Things are in a steady state as you make your last-minute preparations.

  Delivery: The big plunge. This is what made the log flume famous. Whether your delivery is vaginal or via c-section, insulin needs come down quickly. If you deliver naturally, labor involves a great deal of . . . well . . . labor. And that means reduced insulin needs, as if you were running or lifting weights. And with any form of delivery, the removal of the placenta means a sharp drop-off in hormones that were causing insulin resistance.