Guidelines for Exercising Safely with Diabetes

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Living with diabetes doesn’t mean you have to give up physical activity. In fact, exercise is a foundation of diabetes management that helps you manage blood sugar levels and lowers your risk of heart disease and other complications. However, exercising with diabetes does require thoughtful planning, careful monitoring, and an understanding of how your body responds to physical activity. This comprehensive guide will walk you through everything you need to know about exercising safely and effectively with diabetes.

Understanding the Benefits of Exercise for Diabetes Management

Exercise can help you improve your blood sugar levels, boost your overall fitness, manage your weight, lower your risk of heart disease and stroke, and improve your well-being. For individuals with type 2 diabetes specifically, exercise improves blood glucose control, reduces cardiovascular risk factors, contributes to weight loss, and improves well-being.

The benefits extend beyond just blood sugar control. Regular exercise also has considerable health benefits for people with type 1 diabetes, including improved cardiovascular fitness, muscle strength, and insulin sensitivity. Regular exercise may prevent or delay type 2 diabetes development in those at risk.

Physical activity works by increasing glucose uptake into active muscles. During exercise, contractions increase blood glucose uptake to supplement intramuscular glycogenolysis, and blood glucose uptake into working muscle is normal even when insulin-mediated uptake is impaired in type 2 diabetes. This makes exercise a powerful tool for managing blood sugar levels naturally.

How Much Exercise Do You Need?

Recommendations for Adults with Diabetes

The goal is to get at least 150 minutes of moderate-intensity physical activity every week, and one way to reach that goal is to be active for 30 minutes on most days. More specifically, adults with type 1 diabetes and type 2 diabetes should engage in 150 minutes or more of moderate- to vigorous-intensity aerobic activity per week, spread over at least 3 days per week, with no more than 2 consecutive days without activity.

For those who are more physically fit, shorter durations (minimum 75 minutes per week) of vigorous-intensity or interval training may be sufficient for more physically fit individuals. The American Diabetes Association and the World Health Organization recommend 150-300 minutes of moderate-intensity aerobic physical activity or 75-150 minutes of vigorous-intensity aerobic physical activity per week plus strength/resistance training two or more times a week for adults living with diabetes.

In addition to aerobic exercise, adults with type 1 diabetes and type 2 diabetes should engage in 2-3 sessions per week of resistance exercise on nonconsecutive days. This combination of aerobic and resistance training provides the most comprehensive benefits for diabetes management.

Recommendations for Children and Teens with Diabetes

Children and teens with diabetes should get at least 60 minutes of moderate to vigorous aerobic activity every day and should do muscle- and bone-strengthening activities at least three days a week. Examples of muscle-strengthening activities include games such as tug of war and exercises using body weight or resistance bands, while bone-strengthening activities include jumping rope and running.

Breaking Up Sedentary Time

Beyond structured exercise sessions, it’s important to reduce prolonged sitting throughout the day. Prolonged sitting should be interrupted at least every 30 minutes for blood glucose and other benefits. Simple activities like standing up, stretching, or taking a brief walk can make a significant difference in blood sugar management.

Preparing for Exercise: Essential Pre-Workout Steps

Consulting with Your Healthcare Provider

Before you start a new fitness program, talk with your healthcare professional and ask if it’s OK to do the type of exercise you want to try, especially if you have type 1 diabetes. Your healthcare team can help you understand several important factors, including how the activities you want to do might affect your blood sugar, when is the best time of day for you to exercise, and how the diabetes medicines you take might affect your blood sugar as you become more active.

The good news is that most guidelines indicate that a clinical pre-exercise evaluation is not necessary for moderate intensity exercise for asymptomatic individuals with type 2 diabetes. However, conducting clinical assessments beyond routine type 2 diabetes management may be advisable for individuals who have cardiovascular risk factors, diabetes complications, or intend to participate in high intensity exercise, especially if they were previously sedentary or inactive.

Understanding Blood Sugar Testing Needs

If you take insulin or other medicines that can cause low blood sugar, test your blood sugar 15 to 30 minutes before exercising. However, if you manage type 2 diabetes without medicines, you likely won’t need to check your blood sugar before exercise.

The frequency of blood sugar monitoring depends on your individual situation. Individuals with type 1 diabetes should check their glucose level every 30 minutes during exercise and again after exercise. For people with type 2 diabetes managed with medications other than insulin or sulphonylureas (or with lifestyle alone), ongoing pre-exercise glucose testing is not generally necessary due to the low risk of hypoglycaemia.

Medication and Insulin Adjustments

Depending on your treatment, your healthcare professional may tell you to adjust your medicine dose or the food you eat before exercise. A common recommendation is to adjust insulin dosage to prevent exercise-induced hypoglycaemia, achieved by either reducing the dose or supplementing with carbohydrates during or after physical activity.

Understanding insulin-on-board is crucial for those taking insulin. If taking insulin, check your Insulin-on-Board (IOB) before starting exercise, as it may help to decide whether you need a snack to prevent hypoglycemia, and the more insulin you have on board, the higher the likelihood of a low glucose.

Blood Sugar Guidelines for Safe Exercise

When Blood Sugar Is Too Low

Hypoglycemia, or low blood sugar, is a significant concern during exercise. Exercise can cause blood sugar to become too low in people who take insulin. Low blood sugar is mainly a risk for people with diabetes who take insulin or other medicines linked to low blood sugar levels.

If blood glucose is less than 80 mg/dL, eat a minimum of 30 grams of carbohydrates and wait 15 minutes prior to exercising. If you experience low blood sugar during exercise, follow the 15-15 rule: take 15 grams of fast-acting carbohydrates, wait 15 minutes, check your glucose level again, and if it’s still below 70 mg/dL, repeat the cycle.

When Blood Sugar Is Too High

If your blood glucose is higher than 250 mg/dL, exercise may be detrimental. However, the recommendations differ between type 1 and type 2 diabetes. While people with type 1 diabetes shouldn’t exercise with high blood glucose, those with type 2 are probably fine to do so, as the American College of Sports Medicine don’t have recommended activity restrictions for people with type 2 diabetes and a blood glucose over 300 mg/dL, as long as they feel well.

For individuals with type 1 diabetes and elevated blood sugar, checking for ketones is essential. If you have ketones, take steps to lower high blood sugar and wait to exercise until your ketone test shows an absence of ketones in your urine.

During Exercise: Monitoring and Safety Strategies

Continuous Blood Sugar Monitoring

If you’re planning a long workout, check your blood sugar every 30 minutes, which is key if you’re trying a new activity or increasing the intensity or length of your workout, as checking every half-hour tells you if your blood sugar level is stable, rising or falling so you can get a sense of whether it’s safe to keep exercising.

Some people with diabetes need to track their blood sugar before, during and after physical activity, which shows how the body responds to exercise and can help prevent blood sugar swings that could be dangerous. This monitoring becomes especially important when starting a new exercise program or changing your routine.

Carbohydrate Intake During Exercise

To prevent hypoglycemia during prolonged (≥30 min), predominantly aerobic exercise, additional carbohydrate intake and/or reductions in insulin are typically required. The amount needed varies based on several factors.

For low- to moderate-intensity aerobic activities lasting 30-60 minutes undertaken when circulating insulin levels are low (i.e., fasting or basal conditions), approximately 10-15 grams of carbohydrate may prevent hypoglycemia. However, for activities performed with relative hyperinsulinemia (after bolus insulin), 30-60 grams of carbohydrate per hour of exercise may be needed.

In some circumstances, it is recommended to eat 15-30 grams of carbohydrate for every 30 minutes to 1 hour of exercise, and energy drinks, energy gels and shot blocks are all good options.

Hydration and Environmental Considerations

Staying properly hydrated is crucial for everyone, but especially important for people with diabetes. Chronic hyperglycemia increases risk through dehydration caused by osmotic diuresis, and some medications that lower blood pressure may also impact hydration and electrolyte balance.

Temperature and humidity can significantly affect blood sugar levels. In hot conditions, blood vessels can dilate and blood glucose may drop. Older adults with diabetes or anyone with autonomic neuropathy, cardiovascular complications, or pulmonary disease should avoid exercising outdoors on very hot and/or humid days.

Safety Equipment and Precautions

Always keep fast-acting carbohydrates readily available during exercise. Make sure you have emergency treatment for hypoglycemia with you while exercising, as this will help you avoid emergency situations.

Consider wearing a medical ID, such as a medical alert bracelet or necklace, which contains information about your condition and lets people know how to help you in an emergency—a safety precaution that may be especially helpful if you use insulin to help manage your type 2 diabetes.

Post-Exercise Care and Recovery

Monitoring After Exercise

Blood sugar monitoring doesn’t stop when your workout ends. Exercise can lower your blood glucose for 24 hours or more after a session. This delayed effect means you need to remain vigilant about monitoring your levels well after you’ve finished exercising.

Effects of exercise can last as long as 24-48 hours, which is why post-exercise monitoring and adjustments are so important. You may want to check your levels more frequently when starting a new fitness regimen.

Post-Exercise Nutrition

After exercising, check your blood sugar levels and eat a balanced snack if levels are low to prevent hypoglycemia. The timing and composition of your post-exercise meal can significantly impact your recovery and blood sugar stability.

Continue monitoring glucose to ensure glycemia is improving or at least being maintained, and if glucose levels are dipping toward hypoglycemic ranges, consume high glycemic index carbohydrates (e.g., banana, sugar beverage) at the time of the event.

Insulin Adjustments After Exercise

For those using insulin pumps, post-exercise adjustments may be necessary. Reduce your basal rate following exercise for 1-2 hours, and if using a pump, set a temporary basal rate to reduce overnight basal rates. These adjustments help prevent delayed hypoglycemia that can occur hours after exercise.

Cool-Down Importance

Gradually cooling down after exercise helps your body recover safely. The warm-up phase facilitates increased blood flow and prepares the musculoskeletal and cardiovascular system for the transition from rest to activity, while cooling down helps mitigate potential post-exercise adverse effects by promoting proper circulatory venous return.

Types of Exercise Safe for People with Diabetes

Aerobic Exercise

Regular aerobic exercise helps manage blood glucose. Effective aerobic activities include walking, swimming, cycling, dancing, and water aerobics. Examples include fast walking or hiking, lap swimming or a water aerobics class.

Walking is particularly accessible and effective. You could start with a 10-minute walk after dinner and build up slowly. Check your blood sugar before and after you take a walk, and you’ll likely see a lower number after.

Being active after meals reduces blood glucose, making post-meal walks an excellent strategy for blood sugar management.

Resistance Training

High-intensity resistance exercise benefits those with type 2 diabetes more than low- to moderate-intensity exercise. Resistance training can include weight lifting, resistance bands, bodyweight exercises, and functional movements.

Although heavier resistance training improves glycemic control and strength more than lighter weights or home-based activities, all resistance training has the potential to result in greater strength, which can translate into improved balance and ability to live independently and undertake activities of daily living.

High-Intensity Interval Training (HIIT)

High-intensity interval training includes short bursts (seconds to minutes) of very intense activity with recovery periods interspersed that may involve a lower intensity activity or rest, and such training has been demonstrated to result in greater insulin sensitivity and better overall blood glucose levels, at least in adults with type 2 diabetes.

However, HIIT requires careful management for those with type 1 diabetes. Adults with type 1 diabetes can engage in HIIT and manage blood glucose with appropriate regimen changes, which may include more insulin during and following an activity and reduced dosing overnight, along with food intake to prevent overnight hypoglycemia.

Flexibility and Balance Exercises

Yoga, stretching, and balance exercises are valuable components of a comprehensive fitness program. Regular stretching and appropriate progression of activities should be done to manage joint changes and diabetes-related orthopedic limitations.

These low-impact activities can improve flexibility, reduce stress, and enhance overall well-being without causing dramatic blood sugar fluctuations.

Combining Exercise Types

Combining different types of exercise in a single session can provide comprehensive benefits. When both aerobic and resistance exercise are undertaken during a solitary activity session, doing the bout of resistance work first may actually help maintain glycemic balance more effectively than doing aerobic exercise first.

Special Considerations for Diabetes Complications

Cardiovascular Disease

If you have cardiovascular disease along with diabetes, certain precautions are necessary. The Canadian guideline emphasizes the importance of assessing patients with diabetes for myocardial symptoms such as chest pain and severe breathlessness.

Avoid very strenuous activity, heavy lifting or straining, isometric exercises, and exercise in extreme heat or cold; instead, engage in moderate activity such as walking, daily chores, gardening, fishing, moderate dynamic lifting, stretching, and activity in moderate climate.

Peripheral Neuropathy

Peripheral neuropathy affects the nerves in your feet and legs, requiring special attention to footwear and foot care. Those with peripheral neuropathy need to have appropriate footwear and should check their feet every day.

Engage in light to moderate daily activities, exercise in a moderate climate, and moderate weight-bearing activities that are low-impact (e.g., walking, cycling, swimming, chair exercises), and moderate weight-bearing exercises like walking are okay once foot ulcers have healed.

Avoid high-impact, strenuous, or prolonged weight-bearing activities such as walking a long distance, running on a treadmill, jumping/hopping, exercise in heat or cold, and weight-bearing exercise when you have a foot injury, open sore, or ulcer.

Retinopathy

Diabetic retinopathy requires avoiding activities that could increase eye pressure or cause jarring movements. Avoid strenuous exercise, activities that require heavy lifting and straining, breath holding while lifting or pushing, isometric exercise, high-impact activities that cause jarring, and head-down activities; instead, engage in moderate activities that are low impact (e.g., walking, cycling, water exercise) and moderate daily chores that do not involve heavy lifting, straining, or the head to be lower than the waist.

Autonomic Neuropathy

Autonomic neuropathy affects the nerves that control involuntary body functions, including heart rate and blood pressure regulation. Avoid exercise in extreme heat where dehydration can occur and activities requiring rapid changes in movement that may result in fainting, and talk to your doctor before starting an exercise program—you may need an exercise stress test.

Medication Interactions with Exercise

Beta-Blockers

Many people with diabetes are often prescribed β-blockers to manage blood pressure, which blunt heart rate responses to exercise and lower maximal aerobic exercise capacity. However, despite some evidence that β-blockers can reduce awareness of hypoglycemic events, people treated with these agents often increase exercise capacity overall while training.

The rate of perceived exertion (RPE) should be used to monitor intensity in people on β-blockers and avoid the use of heart rate alone.

Statins

Statin use has been shown to increase risk of myopathy and may even blunt exercise adaptations. If you’re taking statins, discuss with your healthcare provider how this might affect your exercise program and what symptoms to watch for.

Non-Insulin Medications

No medication dose adjustments or carbohydrate intake is necessary for other oral diabetes medications or non-insulin injectables, such as GLP-1 agonists. This makes exercise management simpler for those not using insulin or insulin secretagogues.

Factors That Affect Blood Sugar Response to Exercise

Understanding the various factors that influence how your blood sugar responds to exercise can help you better manage your diabetes during physical activity.

Fitness Level

If you’re less fit, blood glucose can drop quickly. As your fitness improves over time, your body’s response to exercise may change, requiring adjustments to your management strategy.

Type of Exercise

Anaerobic exercise may raise blood glucose initially, while aerobic exercise is more likely to have an immediate effect on lowering blood glucose. Understanding these different responses helps you plan appropriate carbohydrate intake and insulin adjustments.

Time of Day

Insulin sensitivity changes during the day: you may be less sensitive early in the day—you may need to “break-the-fast,” but take less medication with food; you’re more sensitive in the afternoon and evening, which may increase your risk of hypoglycemia. This circadian variation in insulin sensitivity should inform when you schedule your workouts.

Hydration Status

If you’re dehydrated, your blood glucose may rise. Maintaining proper hydration before, during, and after exercise is essential for optimal blood sugar control.

Creating Your Personalized Exercise Plan

Starting Slowly and Progressing Safely

If you’re new to exercise or returning after a period of inactivity, start slowly and gradually increase intensity and duration. You could start with exercises to increase your strength and stability. Be sure to check with your doctor about which activities are best for you and also ask if there are any you should avoid.

When initiating an exercise program or when implementing significant exercise program changes (e.g., increases in mode, intensity and duration), additional glucose testing is needed to understand the effects of the exercise on blood glucose and to avoid post-exercise hypoglycaemia.

Tracking Your Response

Establishing the glucose trend before, during and after exercise will educate and inform the exercise specialist regarding the effects of exercise on that individual. Keep a log of your blood sugar readings, the type and duration of exercise, food intake, and insulin doses to identify patterns and optimize your management strategy.

Working with Exercise Professionals

Exercise with a friend or in a group if you are new to exercising. Consider working with exercise professionals who have experience with diabetes management. Exercise intervention studies showing the greatest effect on blood glucose control have all involved supervision of exercise sessions by qualified exercise trainers.

Overcoming Common Barriers to Exercise

Fear of Hypoglycemia

Fear of low blood sugar is one of the most common barriers preventing people with diabetes from exercising. This fear is understandable but can be managed through proper planning, monitoring, and preparation. Always carry fast-acting carbohydrates, monitor your blood sugar regularly, and learn to recognize the early signs of hypoglycemia.

Time Constraints

You don’t need to complete all your exercise in one session. Breaking up activity throughout the day can be just as effective. Walk during lunch or dance to some tunes at home. Even brief activity breaks throughout the day contribute to your overall physical activity goals.

Lack of Motivation

Finding activities you enjoy makes it easier to stick with an exercise program. Try different types of exercise to discover what you like best. Setting realistic goals, tracking your progress, and celebrating small victories can help maintain motivation over time.

Technology and Tools for Exercise Management

Continuous Glucose Monitors (CGM)

If you use a continuous glucose monitor to track your blood sugar, talk with your healthcare professional about how to interpret the data during exercise. CGMs can provide real-time feedback on how your blood sugar is trending, allowing you to make immediate adjustments.

Automated Insulin Delivery Systems

In recent years, the availability of automated insulin delivery (AID) systems has expanded the options for individuals with type 1 diabetes to achieve recommended glucose target ranges. However, a physically active lifestyle offers clear health benefits but can also cause glucose fluctuations, which present a challenge for current AID systems.

Fitness Trackers and Apps

Fitness trackers can help you monitor your activity levels, heart rate, and exercise duration. When using step counters, adults with type 2 diabetes should initially set tolerable targets for steps per day before progressing toward higher goals. Many apps can also help track insulin-on-board and provide reminders for blood sugar testing.

Nutrition Strategies to Support Exercise

Pre-Exercise Nutrition

Eat a snack with carbohydrates (and protein) one hour prior to exercise if needed. The composition and timing of your pre-exercise meal should be based on your current blood sugar level, insulin-on-board, and the planned intensity and duration of your workout.

During-Exercise Fueling

For longer workouts, having easily digestible carbohydrates available is essential. Sports drinks, glucose tablets, gels, and fruit are all effective options for maintaining blood sugar during extended exercise sessions.

Post-Exercise Recovery Nutrition

After exercise, consuming a balanced meal or snack that includes both carbohydrates and protein helps replenish glycogen stores and supports muscle recovery. This is particularly important for preventing delayed hypoglycemia in the hours following your workout.

Exercise Recommendations for Specific Populations

Older Adults with Diabetes

Older adults may face additional challenges, including reduced awareness of hypoglycemia and increased risk of complications. With increasing age, poor blood glucose control, and neuropathy, skin blood flow and sweating may be impaired in adults with type 1 and type 2 diabetes, increasing the risk of heat-related illness.

Focus on exercises that improve balance, strength, and flexibility to reduce fall risk and maintain independence. Low-impact activities like walking, water aerobics, and chair exercises are often excellent choices.

People with Prediabetes

For those with prediabetes, exercise is a powerful tool for prevention. Compared with usual care, diet and physical activity promotion programs reduced type 2 diabetes incidence, body weight, and fasting blood glucose while improving other cardiometabolic risk factors.

Gestational Diabetes

Women with gestational diabetes can benefit from appropriate exercise, but should work closely with their healthcare team to ensure safety for both mother and baby. Exercise recommendations may need to be modified based on pregnancy stage and individual circumstances.

Long-Term Exercise Adherence Strategies

Setting Realistic Goals

Start with achievable goals and gradually increase them over time. Rather than aiming for the full 150 minutes per week immediately, you might start with 10-15 minutes of activity several times per week and build from there.

Building a Support System

Having support from family, friends, healthcare providers, and exercise partners can significantly improve adherence. Consider joining a diabetes support group or exercise class specifically designed for people with diabetes.

Varying Your Routine

Incorporating variety into your exercise routine prevents boredom and works different muscle groups. Try alternating between different types of activities throughout the week—walking one day, swimming another, and strength training on another.

Celebrating Progress

Track your improvements in blood sugar control, fitness level, energy, and overall well-being. Recognizing and celebrating these achievements, no matter how small, helps maintain motivation for continued exercise.

When to Seek Medical Attention

While exercise is generally safe for people with diabetes, certain symptoms warrant immediate medical attention. Stop exercising and seek help if you experience:

  • Chest pain or pressure
  • Severe shortness of breath
  • Dizziness or lightheadedness that doesn’t resolve
  • Severe hypoglycemia that doesn’t respond to treatment
  • Unusual pain or discomfort
  • Vision changes
  • Numbness or tingling that’s new or worsening

Always inform your healthcare team about any concerning symptoms you experience during or after exercise so they can help adjust your management plan accordingly.

Additional Resources and Support

For more comprehensive information about diabetes management and exercise, consider exploring resources from reputable organizations:

Conclusion: Embracing an Active Lifestyle with Diabetes

Exercise is one of the most powerful tools available for managing diabetes and improving overall health. While it requires careful planning, monitoring, and adjustment, the benefits far outweigh the challenges. By understanding how exercise affects your blood sugar, working closely with your healthcare team, monitoring appropriately, and making necessary adjustments to medication and nutrition, you can safely enjoy the many benefits of physical activity.

Remember that everyone’s response to exercise is unique. What works for one person may need to be adjusted for another. Be patient with yourself as you learn how your body responds to different types of activity, and don’t hesitate to reach out to your healthcare team with questions or concerns.

Start where you are, use what you have, and do what you can. Every step, every movement, and every workout contributes to better diabetes management and improved quality of life. With the right knowledge, preparation, and support, you can confidently incorporate exercise into your diabetes management plan and enjoy a more active, healthier life.