Written for World Diabetes Day, this blog is written by Professor Richard Bracken, a leading researcher in exercise physiology at Swansea University. His work focuses on understanding how lifestyle, physical activity, and technology can improve health outcomes for people living with diabetes.

Regular physical activity is one of the most powerful tools for people living with diabetes. It supports both physical and mental health, but it also requires careful planning and understanding.

The Benefits of Regular Exercise

For individuals living with diabetes, physical activity is not just beneficial, it’s essential. Regular exercise offers three major advantages:

• Improved Blood Glucose Control: Exercise increases insulin sensitivity and allows muscles to use glucose more effectively. This helps lower both immediate and long-term blood sugar HbA1c levels.
• Reduced Cardiovascular Risk: Physical activity lowers blood pressure, improves cholesterol profiles, and supports weight management — all critical for reducing the risk of heart disease and stroke, which are more common in diabetes.
• Enhanced Well-being: Exercise boosts energy, improves sleep, reduces stress, and enhances overall mental health, helping individuals feel more empowered in their condition management.

How the Body Responds Differently to Exercise with Diabetes

The biggest difference between someone with diabetes and someone without diabetes lies in how blood sugar is regulated during activity. In people without diabetes, hormones like glucagon and adrenaline automatically adjust to keep blood sugar stable. For those with diabetes, especially those using insulin, this self-regulation is impaired, meaning they must manually balance insulin doses.

• Aerobic exercise, such as running or cycling, can lead to hypoglycemia (low blood sugar) as muscles rapidly take up glucose.
• Anaerobic or high-intensity exercise, like sprinting or heavy lifting, can trigger hyperglycemia (high blood sugar) due to stress hormone release. This makes blood glucose monitoring before, during, and after activity crucial for safety and performance.

The Best Types of Exercise for People with Diabetes

Different forms of exercise affect blood glucose in unique ways:

Exercise Type	Primary Effect on Blood Glucose	Diabetes Type	Key Considerations
Aerobic (e.g. brisk walking, jogging, cycling)	Lowers BG (uses glucose for fuel)	T1 & T2	Improves insulin sensitivity but may cause hypoglycemia
Anaerobic/HIIT (e.g. heavy weightlifting, sprinting, HIIT)	Raises BG temporarily (due to stress hormones releasing stored glucose)	T1	May cause hyperglycemia, requires caerful insulin dosing afterward
Resistance Training (Strength)	Builds muscle mass, which improves long-term insulin sensitivity and glucose uptake	T1 & T2	Causes hyperglycemia for T1 but builds muscle and supports long-term blood glucose control for both types
Combined Training (Aerobic and Resistance)	Optimises blood glucose control and cardiovascular health	T2	Most effective for lowering HbA1c over time

Managing Risks and Overcoming Fear

The fear of hypoglycemia remains the single greatest barrier to exercise in diabetes, especially among insulin users. Intense workouts can also raise glucose levels or, in rare cases, lead to diabetic ketoacidosis (DKA) if insulin levels are too low.

These risks can be managed through:

• Education: Working with healthcare providers to develop individualised plans for insulin adjustment, carb intake, and safe blood glucose ranges during exercise.
• Research & Technology: Modern devices like Continuous Glucose Monitors (CGMs) and automated insulin pumps can predict and prevent dangerous glucose swings.

Making Sport Inclusive

Coaches and fitness professionals play a vital role in creating inclusive environments for athletes with diabetes:

• Learn the Basics: Understanding the differences between Type 1 and Type 2 diabetes, recognising signs of low or high blood sugar and having knowledge of the immediate treatment.
• Encourage Open Dialogue: Athletes should feel safe to pause, test, or treat symptoms during training.
• Plan Ahead: Having emergency carbs and glucagon kits accessible, and adapting training based on real-time glucose data.

The Role of Technology

Technology is transforming diabetes management, especially in sport. Continuous Glucose Monitors provide real-time feedback and trend data, helping athletes act before glucose levels become unsafe. Insulin Pumps and Automated Delivery Systems allow flexible dosing, reducing insulin before activity to prevent low blood sugar, and restoring normal function post-exercise. These advances empower those with diabetes to train with confidence, reducing fear and maximising performance.

Progress and Remaining Gaps in Awareness

Public understanding of exercise in diabetes management has improved dramatically, particularly for Type 2 diabetes. However, there are still knowledge gaps, especially around insulin adjustment, carb timing, and managing fear of hypoglycemia. Socioeconomic barriers also limit access to personalised guidance and advanced technology.

Turning Science into Action

Translating research into practical advice involves three key steps:

1. Simplification: Convert complex data into clear, actionable guidance (e.g. Walk 30 minutes a day to lower your long-term blood sugar).
2. Integration: Update Clinical Practice Guidelines and training for healthcare teams.
3. Individualisation: Help each person apply these principles safely within their lifestyle.

Ongoing Research Needs

Despite progress, many questions remain:

• Why do individuals with the same diabetes type respond differently to exercise?
• What are the best combinations of exercise and nutrition for different populations?
• How can we best integrate new technology into daily management?

More large-scale, long-term studies are needed, particularly for underrepresented groups such as children, older adults, and pregnant women with diabetes.

Top Tip

Monitor your blood glucose closely (before, during, and after exercise), and proactively adjust insulin or carbohydrate intake.

Research shows that reducing basal insulin by 50–80% before aerobic activity (via pump) or consuming a carb snack before exercise (for those on injections) is the most effective way to prevent hypoglycemia.

Looking Ahead

As part of an international collaboration of scientists, clinicians, and people living with diabetes, our team continues to refine global consensus guidelines for safe exercise, Continuous Glucose Monitor use during activity, and automated insulin delivery.

The goal is simple: to make physical activity safe and empowering for every person with diabetes – transforming fear into freedom through knowledge, technology, and movement.

If you’re interested in learning more about our research at Swansea University or collaborating with our academics, clinicians or companies on future work, let us know below.