When you have Diabetes and are treated with insulin:
The goal of your checklist and FAQs is to help ensure more predictable blood glucose results and to prevent low blood glucose when you are treated with insulin. You can refer to
exericse principles for Diabetes for more information,
Checklist:
- Know your blood glucose level before starting any significant activity or exercise.
- If you are low, you need to eat a rapidly acting carbohydrate snack
- If you are high, you may need to delay your exercise. If you exercise when you have ketones or when the blood glucose is very high (over 250 mg/dl), you may drive your blood glucose even higher.
- Check the blood glucose level as needed throughout exercise.
- Be prepared to snack.
- Snack as needed to prevent low blood glucose during exercise. Ideally, the snack should be a liquid or readily absorbed form of simple carbohydrate.
- When deciding how many carbohydrates to eat, take into account the type, duration and intensity of the exercise, as well as your pre-exercise blood glucose reading.
- Know, too, how much insulin is still active from the last injection.
- If the activity is prolonged, carbohydrate snacks are periodically required.
- For example, if you are biking uphill, you will need to check blood glucose frequently, stay hydrated and may need to take in additional carbohydrate at various intervals of actitvy, to prevent hypoglycemia. Frequent monitoring is important in this situation.
Warning: Do not take insulin to cover exercise-related snacks or snacks used to prevent or treat a low blood glucose!
FAQs
Will exercise cause low blood glucose?
In general, the longer, more vigorous, and more intense the exercise, the more likely that the exercise will lower the blood glucose. So when you are exercising, you may need to lower the dose of your insulin, and eat more carbohydrates to prevent low blood glucose related to exercise. The converse also is true – brief, non-strenuous exercise may not require any insulin dose or diet adjustment.
When should your insulin dose be adjusted?
Because exercise generally increases insulin sensitivity, a lower dose of insulin may be needed. Exercising every day may require an overall reduction in your insulin dose. Exercising every once in a while may require a dose reduction just on the day of your intermittent exercise. Check with your health care provider for specific insulin dose adjustment recommendations.
What kind of food should I take to prevent or treat a low blood glucose during exercise?
It may be necessary to eat a
carbohydrate-containing snack to prevent low blood glucose especially if the exercise is unplanned or prolonged. Ideally, the snack should be a liquid or readily absorbed form of simple carbohydrate. Remember that complex carbohydrate takes a longer time to digest. If the food is high fat or oily, the stomach will empty more slowly and the absorption of the sugar is delayed. High-fat or complex carbohydrate containing snacks may increase the risk of exercise-related low blood glucose.
Does the time of day of the exercise matter?
The change in insulin sensitivity throughout the day is important to understand, because if you exercise when you are more insulin sensitive, you may be at greater risk for low blood glucose . To prevent low blood glucose, you may need to lower the dose of insulin, eat more carbohydrate or both. Check with your medical provider for specific recommendations. The converse also is true. Exercising during periods of insulin resistance may have less blood glucose-lowering effects, so fewer adjustments to insulin dose and carbohydrate intake may be needed.
Is your exercise predictable?
Try to exercise at the same time of day, for the same amount of time and at the same level of exertion. This will ensure the most predictable blood glucose response. Whenever you exercise, you have to match the duration and intensity of exercise with other factors such as natural body rhythms or changes in insulin sensitivity that occur throughout the day, peak insulin effect and the content of meals.
Have you been drinking alcohol while exercising?
Remember!
Alcohol alone can reduce the amount of glucose produced by the liver, and can put you at risk for a low blood glucose. Alcohol and exercise in combination increase the risk of a low blood glucose. Examples of exercise include running, swimming and dancing. The combination of activities promote low blood glucose, and this can lead to such severe lows that you pass out. Should that happen, it might be difficult to know whether you have had too much to drink or are suffering from low blood glucose.
Are you sick or stressed?
Understand what happens when you’re sick, stressed, or fatigued. Any sort of
stress will make you less sensitive to insulin. If you are sick or stressed or exceptionally fatigued, you will release more glucose counter-regulatory hormones. As a result, the exercise may have less of a glucose-lowering effect.
How long does the blood glucose lowering effect of exercise last?
The blood-glucose lowering effect of exercise can vary in duration. Depending upon your level of physical training, and the intensity and duration of exercise, you may be more sensitive to insulin for hours or even into the next day after exercise. When you exercise every day, you body becomes overall more sensitive. However, if you stop exercising, in a few days the increased sensitivity will wear off as well.
Here are some points to keep in mind:
- People who work out or are physically active on a daily basis may need to lower the total daily dose of their insulin.
- For people who exercise more sporadically, the acute effect of exercise on insulin sensitivity may last hours to half-a-day and may require the insulin dose to be lowered just around the time of the exercise.
- Unusually prolonged or vigorous activity may result in a decrease in insulin dose requirements, overnight and even into the next day.
Is your blood glucose unexpectedly high following exercise?
When the blood glucose is unexpectedly high after exercise, think about why. Generally, exercise will lower your blood glucose. If the post- exercise blood glucose reading is unexpectedly high, you may need to consider if your blood glucose dropped so low during the activity that your body re-regulated itself by releasing
counter-regulatory hormones. If so, the subsequent rebound can cause a high blood glucose reading. Other considerations might be overestimating the impact of the exercise, engaging in a stressful kind of exercise (such as weight lifting) and eating too much carbohydrate beforehand.
Are you trying to lose weight?
Try to optimize your dose of insulin so that you can avoid exercise related low blood glucose reactions and the need for extra exercise-related snacks. Fewer snacks means fewer calories!