Exercise and Diabetes: What You Need to Know Before You Move
Managing diabetes can be complex, but exercise is one of the most powerful tools we have to help regulate blood sugar, improve cardiovascular health, and enhance quality of life. At the Online Exercise Clinic, we specialize in hospital-grade exercise counselling for individuals living with chronic diseases and disabilities—diabetes included.
In this post, we’ll explore how to safely and effectively incorporate physical activity into your diabetes care plan, using evidence-based guidelines from the American College of Sports Medicine (ACSM). Whether you’re living with type 1 or type 2 diabetes, our goal is to help you move safely and confidently.
Why Exercise Matters for Diabetes
Regular physical activity improves insulin sensitivity, helps regulate blood glucose levels, and supports healthy weight management. In both type 1 and type 2 diabetes, exercise can:
Lower blood sugar levels during and after activity
Reduce A1C (a marker of long-term glucose control)
Improve cardiovascular and muscular endurance
Enhance mood and mental health
Exercise for individual with diabetes is generally safe however understanding and managing blood sugar levels, especially for those taking insulin, is key to preventing problems and most notably hypoglycemia.
What is hypoglycemia?
Hypoglycemia occurs when your blood glucose drops below normal levels—typically under 3.9 mmol/L (70 mg/dL). It can happen during or after exercise due to increased insulin sensitivity and glucose uptake by working muscles. Symptoms of hypoglycemia include shakiness, sweating, irritability, dizziness, fatigue, and confusion. If left untreated, it can lead to more serious complications like loss of consciousness or seizures. That’s why it’s crucial to recognize the signs early and treat with 15–30 grams of fast-acting carbohydrates.
Pre-Exercise Blood Glucose Targets
If you are taking insulin, it is important to know you blood sugar levels before starting any workout.
Safe to exercise: 5.5 to 13.9 mmol/L (100 to 250 mg/dL)
Caution zone: <5.5 mmol/L (<100 mg/dL) — you’ll need a carb snack before starting
Too high: >13.9 mmol/L (>250 mg/dL) — check for ketones if you have type 1 diabetes and consult your care team if ketones are present
If your glucose is below 5.5 mmol/L (100 mg/dL), consume 15 to 30 grams of fast-acting carbohydrates (such as 4 glucose tablets, 120–180 mL of juice, or a tablespoon of honey) and wait 15 minutes before rechecking.
During Exercise: Watch for Hypoglycemia
Exercise, especially moderate to vigorous activity, can lower your blood sugar. This effect may persist for several hours post-exercise. It’s important to stay aware of hypoglycemia symptoms such as shakiness, sweating, dizziness, or confusion.
Tips:
Keep a source of fast-acting carbohydrates with you at all times.
Monitor your blood sugar every 30–60 minutes during prolonged sessions.
Stay hydrated and avoid exercising alone if you’re prone to low blood sugars.
Managing Hypoglycemia During Exercise
If your blood sugar drops during exercise (below 3.9 mmol/L or 70 mg/dL), it’s important to act quickly. Stop exercising immediately and consume 15–30 grams of fast-acting carbohydrates, such as glucose tablets, juice (120–180 mL or 4–6 oz), regular soda (not diet), or candy like jellybeans. Recheck your blood sugar after 15 minutes. If it remains low, repeat the carbohydrate intake. Once your blood sugar has stabilized above 5.5 mmol/L (100 mg/dL), you should end the exercise session for the day. It’s recommended to follow up with a solid meal containing carbohydrates and protein to help maintain stable blood sugar levels and prevent further drops.
Post-Exercise Glucose Monitoring
After exercise, blood sugar levels may drop, especially following high-intensity or long-duration workouts. Diabetics can experience continued drops in blood sugar for up to 24 hours, with the greatest risk typically occurring within 6 to 15 hours post-exercise.
This happens because exercise increases insulin sensitivity, meaning your muscles continue to pull glucose from the blood for recovery even after you’ve stopped moving. The risk is higher after moderate to vigorous intensity or long-duration exercise sessions. To manage this:
Check blood sugar immediately after your session and again 2–3 hours later.
If your blood sugar is below 5.5 mmol/L (100 mg/dL) post-exercise, consume 15–30 grams of carbs.
Consider a balanced post-exercise meal or snack that includes both carbohydrates and protein to stabilize glucose levels.
Carbohydrate Supplementation: How Much and When?
The amount of carbohydrate you need depends on the duration and intensity of your activity. Here’s a general guide:
Light activity (<30 minutes): Usually no extra carbs needed if pre-exercise glucose is in target range
Moderate intensity (30–60 minutes): 15–30 grams of carbs may be required before or during exercise
High intensity or >60 minutes: 30–60 grams of carbs per hour may be needed during exercise
Always adjust your intake based on your blood glucose trends and how your body responds to exercise.
Final Thoughts
Exercise is a cornerstone of diabetes management, but it requires careful planning and individualized attention—especially when you’re living with other chronic conditions. At the Online Exercise Clinic, our Exercise Physiologists ensure your activity plan is safe, effective, and tailored to your needs.
Whether you’re newly diagnosed or navigating life-long diabetes, we’re here to support you every step of the way.
Need help creating a personalized exercise plan? Book your virtual consultation today!
If you have any questions about how a Clinical Exercise Physiologist can help you achieve you health and fitness goals please reach out to us at info@onlineexerciseclinic.com.
The information in the blog is provided for informational and educational purposes only and does not constitute medical advice. The information is not a substitute for professional medical advice, diagnosis, or treatment. For questions please follow up with your healthcare professional.
