In this section, you will find:
Why am I having low blood sugars?
Possible causes include:
“Stacking” insulin
It can be tempting to correct a high blood sugar; however, taking frequent corrective doses of
insulin is one of the most common causes of low blood sugars.
The solution: Rapid-acting insulin lasts about 4 hours. If you inject another corrective dose within that time frame, the dose should be decreased to account for the amount of insulin still active from the previous injection.
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Eating less carbohydrate than anticipated
Sometimes we don’t eat what we plan to, or we miscount
carbohydrates because we don’t know the carbohydrate content of the food. When this happens, a low blood sugar may occur.
The solution: If you eat less than expected, make up the “missing” grams of carbohydrate by eating them as fresh fruit or dextrose tablets. If you are not sure of the carbohydrate content of the food, check your blood sugar more often and be prepared to take supplemental sugar.
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Excessive insulin-to-carbohydrate ratio
Having too much insulin to cover the carbohydrate (ie an excessive insulin-to-carbohydrate ratio.) A clue is having a low blood sugar within the first few hours after a meal. Be sure that the low is not due to incorrect carbohydrate counting, a meal high in fat or fiber, leftover insulin effect from a previous high blood sugar correction, or unusual exertion.
The solution: Reduce the amount of insulin you are using to cover the carbohydrate for the meal or snack. As always, consult with your medical provider for specific insulin dose recommendations.
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Excessive basal insulin
How do you know if your basal dose is wrong? Look at the blood sugars overnight and before meals. These times are most reflective of the basal insulin dose, and are the least affected by bolus insulin. Double-check other factors by asking these questions: Are the mealtime bolus dose and the high blood glucose correction causing the low? Has your last rapid-acting insulin dose completely worn off? Have you engaged in any unusual physical activity or exercise?
The solution: Once you have eliminated these possibilities, consult with your diabetes medical team about reducing your basal dose of insulin.
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Delayed eating after taking mealtime insulin
Life is full of delays, so it’s not uncommon to anticipate eating a meal, take your insulin and then to have something happen that delays the meal. This is particularly true when going out to eat.
The solution: Take rapid-acting insulin for the carbohydrates only when the meal is right in front of you. Seeing what is actually being served will also help you choose the best insulin dose.
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Increased activity or exercise
Exercise generally makes the body more sensitive to the action of insulin.
The solution: Scale back insulin doses, and increase carbohydrate consumption in order to prevent low blood sugar. Consult your diabetes medical team about any dose adjustment for exercise.
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Delayed stomach (gastric) emptying
This condition can be caused by a high fat or high fiber meal,
stomach neuropathy (gastroparesis) or medications such as exenitide or Pramlintide. In each case, the insulin acts before the carbohydrate portion of the meal is released into the intestine and absorbed.
The solution: Avoid high fat or high fiber meals, and if gastroparesis is present, eat small, relatively liquid meals and consume carbohydrate foods first. You may benefit from taking part of the mealtime insulin beforehand and the rest after eating, or, if you are using an insulin pump, use the extended bolus feature. If you are taking exenatide or Pramlintide before a meal, you will need to reduce your mealtime insulin dose. Consult your medical provider about specific insulin dose recommendations.
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Fear of complications
For some individuals, the fear of
complications from high blood glucose is so overwhelming that they prefer risking low blood sugar to the health consequences of chronic highs. This is a dangerous trade-off. Low blood sugar can cause immediate, even life-threatening harm.
The solution: Reduce the insulin dose until the low blood sugars are eliminated. Discuss insulin dose adjustments with your medical provider.
Taking the wrong insulin by mistake
Sometimes people take rapid-acting insulin instead of long-acting insulin by mistake and get a low blood sugar. This can be a problem with insulin pens, as they can look alike. Clear long-acting insulin, such as
glargine or detemir, can be confused with clear short- or rapid-acting insulin.
The solution: Always double check that you are injecting the correct insulin.
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Drinking alcohol
Alcohol can reduce the amount of glucose produced by the liver and can put you at risk for a low blood sugar.
The solution: Drink alcohol in moderation. Eat carbohydrates when you drink alcohol. Check your blood sugar.
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Increased insulin sensitivity
Losing weight and increased activity can increase your sensitivity to insulin, decreasing your insulin needs. Other less common causes of reduced insulin requirements are kidney problems, low thyroid activity, or loss of glucagon due to a decrease in pancreatic function
. The solution: Discuss with your diabetes team how your other medical diagnoses may affect your basal insulin.
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“Covering” exercise and low blood sugar-related snacks with insulin
You don’t need to take insulin when you’ve eaten a
carbohydrate-containing snack to treat low blood sugars or to prevent lows during exercise.
The solution: Carbohydrate snacks taken to prevent or treat low blood sugars are “free” and don’t require insulin coverage.
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Use of an incretin based therapy or an amylin analog (pramlintide)
Incretin based therapy (exenatide, sitigliptin) or
Pramlintide will lower blood sugars after your meal. In combination with insulin, their use may result in a low blood sugar.
The solution: Decrease the insulin dose, and as needed, the incretin or Pramlintide dose. You may benefit from taking part of your bolus insulin beforehand, and the rest after the meal. If using an insulin pump, consider using an extended bolus. Consult your medical provider for specific recommendations regarding insulin dose adjustment.
Why am I having high blood sugars?
Possible causes include:
Incorrect carbohydrate counting
If your mealtime
carbohydrate count is wrong, your insulin dose will be incorrect as well. This is particularly true when eating out or when eating foods that don’t have nutrition labels
. The solution: Learn more about carbohydrate counting. Weigh and measure your food whenever possible. Eat foods with carbohydrate counts that you already know. Research nutrition information online for food options at restaurants and chain outlets.
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“Out-eating” the insulin
It’s not always easy to anticipate how much you will actually eat during a meal. However, missing the mark has the same effect as if you miscounted carbohydrates. Moreover, there are individual limits on how much mealtime carbohydrate can realistically be covered.
The solution: If you decide to eat more than you planned, you will need to take more insulin to cover the additional carbohydrates. In general it’s wise to limit your mealtime consumption of carbohydrate to less than 60-75g or to whatever has been recommended by your nutritionist. If you have a special occasion coming up, be sure to discuss any special “party meal” or “banquet” medication dose adjustment with your medical provider.
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Insufficient insulin coverage of the carbohydrate (ie Inadequate insulin-to-carbohydrate ratio)
It is important to know how many grams of carbohydrate are covered by one unit of insulin – this is your insulin-to-carbohydrate ratio. If you think the ratio is out of balance, ask yourself these questions. Did you count the carbohydrates correctly? Did you take the proper blood sugar correction dose before you ate? Were you more or less active than usual? Under any unusual stress
? The solution: Once you have eliminated these variables, you may need to adjust the insulin-to-carbohydrate ratio to get more insulin at the meal or snack. Consult your medical provider about insulin dose adjustments.
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Inadequate basal insulin dose
An insufficient basal insulin dose can cause a high blood sugar reading. To be sure that this is the cause of your high blood sugar, you’ll need to do some detective work. First, check your blood sugar readings overnight and before meals. These readings are least likely to be affected by meal or correction boluses. Second, check that the insulin-to-carbohydrate ratio, high blood sugar correction, or change in your activity and stress level isn’t causing the high blood sugar.
The solution: Once you have eliminated these variables, if the readings are still high, consider increasing the amount of your basal dose in consultation with your diabetes medical team.
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Rebound from a low blood glucose
The body’s natural response is to maintain balance. Low blood sugar is no exception. The body releases
glucose counter-regulatory hormones that raise the blood sugar. The effects of these hormones may last for 6-8 hours. To stop the highs, you need to stop the lows.
The solution: Adjust the insulin doses to prevent low blood sugars. Discuss with your medical provider the causes of why you are getting low blood sugars.
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Delayed stomach (gastric) emptying
This condition can be caused by a high fat or high fiber meal,
stomach neuropathy (gastroparesis), or by medications such as exenatide or pramlintide. In each case, the insulin action is almost over by the time the carbohydrate portion of the meal is released into the intestine and absorbed. The classic pattern is a low blood sugar in the early part of the meal followed by a high blood sugar for many hours after.
The solution: Avoid high fat or high fiber meals. If gastroparesis is present, eat small, relatively liquid meals and consume carbohydrate foods first.
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Taking too little insulin because of fear of low blood sugars
The symptoms of low blood sugar can be very uncomfortable, so it’s no surprise that people sometimes overreact by taking less insulin than is necessary.
The solution: Gradually increase your insulin doses so that you become familiar with what amount is best. Consult with your medical provider regarding any insulin dose adjustments.
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Not monitoring blood glucose levels
If you don’t
check your blood sugar regularly, you may be unaware of high blood sugar.
The solution: Check your blood sugar at regular intervals (no less than 4 times a day), and adjust your insulin dose as recommended by your provider.
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“Needle phobia”
Some people just don’t like taking insulin injections – even after years of having diabetes and knowing how important they are.
The solution: Consider using an alternative delivery system, such as an insulin pump or pen.
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Taking medications that cause insulin resistance
Occasionally it may be necessary to take medications, such as steroids or niacin, that lead to insulin resistance.
The solution: Work with your diabetes team to adjust your insulin dose to maintain glucose control.
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Inactivity
Any decrease in your usual activity can decrease your insulin sensitivity and increase your insulin requirements.
The solution: Monitor your blood sugar levels closely and adjust your insulin replacement accordingly.
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Weight gain
Increased weight causes resistance to the action of insulin. Weight gain is a very common cause of an increased insulin dose requirement
The solution: Watch your calories and watch your weight. If you find you are gaining weight cut back on how much you are eating and consult with your nutritionist.
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Increase in stress hormones
There are many reasons why your
stress hormones might spike: Infections, physical and emotional stress, medical conditions like thyroid or liver disease, pregnancy or puberty
. The solution: Work with your diabetes team to adjust your insulin dose to maintain glucose control.
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Bad (spoiled) insulin
Insulin won’t work if it gets too hot or too cold. And it will spoil if the cartridges or vials are left open for too long.
The solution: Look at the package insert and follow the storage instructions. If you think your insulin is spoiled, use a new cartridge or vial. Remember never to place insulin in direct sunlight, leave it in a hot car, or place it too close to the freezer section in the refrigerator. Always keep your insulin supplies with you when traveling.
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Incorrect insulin injection technique
Technique is important because things like air bubbles in the syringe or cartridge, leakage from the injection site or simply measuring out the wrong amount, can result in an incorrect insulin dose. There is a proper technique for insulin injection.
The solution: Check for bubbles, and if you use a pen device, clear the air from the syringe or cartridge with a test dose before administering the insulin. To prevent leakage from the injection site, count to 10 before withdrawing the needle from the skin. Double-check the insulin dose before injecting.
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Injecting into scarred or overused areas
Repeated insulin injections in the same area can lead to scarring, which may interfere with insulin absorption
. The solution: Avoid overusing one area. Rotate your insulin injection sites.
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Taking the wrong insulin by mistake
Sometimes people get a high blood sugar reading because they mistakenly inject long-acting insulin instead of short- or
rapid-acting insulin. This is particularly a problem when using pens to administer insulin as all pens (including those for
long-acting agents, such as Lantus and Levemir) tend to look alike
.