Hypoglycemia, or low blood sugar, during or after exercise is a common occurrence in people with type 1 diabetes and sometimes occurs in those with type 2 diabetes as well. If you’ve ever experienced dizziness, shakiness, fainting, or nausea during physical activity, chances are you’ve experienced exercise-induced hypoglycemia.
While regular exercise is recommended to improve your body’s sensitivity to insulin and lower blood glucose levels over the long run, it’s important to learn how to avoid hypoglycemia when exercising. You should always discuss exercise plans and precautions with your healthcare provider to create the regimen that’s safest for you.
How Can Exercise Cause Hypoglycemia?
Glucose, or sugar, is the primary fuel for your muscles during physical activity. When you’re exercising, your muscles are under more strain than normal, which requires them to use more fuel. Your body initially retrieves this fuel from glucose in the bloodstream or from larger glucose stores in the muscles known as glycogen. During strenuous exercise, however, your body will begin to use the glycogen stored in the liver, which can eventually deplete the body’s overall glucose levels. This fueling process is unavoidable, but there are things you can do to keep your blood glucose levels in a healthy range.
How to Optimize Blood Sugar Before Exercise
Optimizing your blood sugar before exercise can help you prevent hypoglycemia. The following are some of the best ways to do this:
- Check your blood sugar before exercising to make sure it’s within a range sufficient for exercise. Generally, your blood sugar should be between 100 and 250 mg/dL.
- If your levels are lower than recommended, eat 15 grams of carbohydrates and wait 15 minutes before testing your blood sugar again. If your blood sugar is now within the healthy range, it’s safe to begin exercising. If your levels are still below 100 mg/dL, have another 15-gram serving of carbohydrates and repeat this every 15 minutes until your blood sugar is at least 100 mg/dL. This is known as the 15/15 rule.
- If your levels are higher than 250 mg/dL and you don’t have ketones (a by-product of your body breaking down body fat for energy that can be measured with a urine test), postpone your workout and consider taking your insulin to lower your blood sugar. If you do have ketones, avoid exercise and discuss precautions or treatment with your healthcare provider.
- Learn how long it takes for your insulin brand to reach peak effectiveness and avoid exercising during that time.
- Avoid exercising before bed to prevent the risk of undetected hypoglycemia while you’re asleep.
- A snack is recommended before any exercise beginning 2 or more hours after your last meal and before or during exercise lasting longer than 1 hour.
- Don’t drink alcoholic beverages before exercise.
- Plan to have a meal high in carbohydrates (around 30 grams) consisting of whole grains, legumes, and/or starchy vegetables at least 3 hours before a workout.
How to Avoid Hypoglycemia When Exercising
Knowing how to avoid hypoglycemia when exercising is essential for people living with diabetes. Including the following habits in your routine will help you stay safe:
- Check your blood sugar every hour if you plan to exercise longer than 2 hours.
- Stop exercising if you have a low blood sugar reading or experience symptoms and follow the 15/15 rule before restarting exercise.
- Keep a fast-acting sugar source nearby in case glucose levels drop during exercise. Options include glucose tablets, juice or regular soda, or a tablespoon of sugar.
- Remain hydrated during exercise.
How to Prevent Hypoglycemia After Exercise
These are some important ways to prevent or help reverse hypoglycemia after exercise:
- Have a meal within an hour following exercise to replenish carbohydrates and protein.
- Check your blood sugar when you finish your workout. If it drops too low, plan to adjust the insulin dosage you take before exercise to prevent low blood sugar next time.
- Avoid very hot places, such as saunas, immediately after exercise. The heat will elevate your heart rate and can continue to deplete your glucose levels.
- Continue checking your blood sugar throughout the day, as your levels may drop for up to 48 hours after an intense workout.
- Don’t drink alcoholic beverages immediately after exercise.
- Adjust your next workout session if your workouts are too intense and lower your blood sugar levels to unsafe levels.
Develop a Safe Routine
A safe workout routine is a valuable part of diabetes management. The key is knowing how to avoid hypoglycemia when exercising. To create a strategy that works for you, talk to your healthcare provider about your plans and keep track of your blood glucose levels. An all-in-one glucose monitor like the POGO Automatic® Monitor is a quick and efficient way to check your blood sugar levels before, during, and after exercise and will give you the confidence to embark on your exercise journey safely.
Jaclyn Owens is a product director specializing in diabetes management tools. She is committed to using technology to empower people with diabetes and help them take control of their health.
All content on this website is for educational purposes only and does not replace the guidance of your healthcare practitioner. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment and before undertaking a new healthcare regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.