Exercise can be a foreboding topic for individuals with diabetes, and even more so when in an unfamiliar setting. However, we believe that individuals with diabetes can take part in any physical activity abroad with the proper forethought and preparation. Not only is exercise a fantastic way to increase blood glucose control, it is also one of the best ways to see a city when you are abroad! Going for a walk, run, or even a bike ride is a guaranteed way to find little alleyways or local shops that you might have missed from a taxi.
It is always a good idea to talk to your diabetes team before exercising, but below are a few guidelines to start you off!
Testing Blood Glucose Levels for Exercise
It is recommended to test and review blood glucose levels every 30 minutes during exercise. Levels should also be checked prior to beginning exercise. If blood glucose levels are 14mmol/L (252mg/dl) or more, then test for ketones. If ketones are not present, proceed with exercise while checking regularly. If ketones are present then do NOT proceed with exercise. Correct this factor and check again.
Adjusting Insulin for Exercise
Knowing whether to reduce basal (background) or bolus (mealtime) insulin is dependent on when the exercise is planned in relation to the time of the last meal bolus insulin injection.
Generally, basal (background) insulin can be adjusted by splitting the dose, taking half in the morning and half in the evening. The dose prior to exercise can be reduced by 20% or more (consult your diabetes team).
Pump users may change the basal infusion rate starting 90 minutes before exercise and continuing until 90 minutes following exercise.
A Basic Model:
- Estimate the amount of carbohydrates in a meal
- Check the exercise carbohydrates for the type and duration of planned exercise
- Subtract the exercise carbs from the meal carbohydrate content
- Calculate the amount of insulin for the meal based on the new calculated carbohydrate content
Adjusting Carbohydrate Intake
Because carbs are the main source of energy during exercise, consuming more of them prior to or during exercise will help to decrease the risk of hypoglycemia.
General approach (based on clinical research): Assume muscles use glucose at rate of 1g/kg (2.2lb) body weight per hour. A 70kg (154lb) adult would therefore need to take 70g of carbs for each hour of exercise, or 35g each half hour.
Advanced approach (for greater specificity): Use online tables to calculate carbohydrate needs. Suggested resource: Diabetesnet.us/node/237
What Are the Risks?
Hypoglycemia: When insulin is present, the liver might not be able to produce glucose. Glucose is demanded by muscles during exercise, and if there is not sufficient glucose present from the liver, there is a risk for hypoglycemia.
Hyperglycemia: The body may respond to exercise in an opposite manner by producing hormones that act to turn on the liver to make more glucose. The hormones decrease the ability of muscles to use the glucose that is being produced, and therefore put an individual at risk of hyperglycemia.
- Eat extra carbohydrates
- Reduce both bolus insulin and background (basal) insulin
- Consider using a correction dose (extra insulin) immediately at end of exercise after checking blood glucose levels