Diabetes and exercise

Regular physical activity is an important part of good health for everyone, including people with diabetes. The right type and amount of exercise depends on your age and your circumstances, such as pregnancy. General physical activity advice applies to people with diabetes too, but speak with your doctor before starting any new activity.

How much activity to aim for#

Common physical activity guidance suggests:

• Children – several hours of varied physical activity each day, including active play such as crawling, walking, jumping and dancing.
• Adults – a regular amount of moderate intensity activity each week (such as brisk walking, golf, mowing the lawn or swimming), plus some vigorous activity (such as jogging, aerobics, fast cycling or team sports).
• Older adults – about 30 minutes of moderate intensity activity on most days, such as walking, shopping or gardening.

None of this needs to be done all at once. Several shorter sessions can add up over the day.

Benefits of exercise#

When combined with healthy eating, exercise can help you to:

• improve mood and sleep
• improve muscle strength and bone mass
• lower blood glucose levels (BGLs)
• lower cholesterol and blood pressure
• improve heart and blood vessel health
• maintain or achieve your healthiest body weight
• reduce stress and tension
• improve mental health

If you are at risk of type 2 diabetes, exercise can be part of a healthy lifestyle that helps reduce this risk.

While exercise has many benefits, it is also important to know some guidelines for diabetes and exercise.

Precautions before starting an exercise program#

Choosing activity that is right for you makes exercise safer and more enjoyable. People with diabetes are at increased risk of heart and blood vessel disease and of foot problems, and some risks increase during and after exercise.

People with type 1 diabetes, and people with type 2 diabetes using insulin or certain glucose-lowering medications called sulphonylureas, are at risk of hypoglycemia. Speak with your doctor if you are unsure of the type of medication you are taking, and make sure you have an individualized diabetes management plan. Your diabetes health professional can help you create one.

If you have never exercised before, start with low impact exercise such as walking and go slowly. This helps build exercise tolerance, makes you more likely to keep exercising regularly, and helps prevent injuries.

Consider seeing an exercise physiologist for an individualized exercise program. This is especially helpful if you have pain or limited movement.

Discuss with your doctor or diabetes educator the most appropriate areas of the body to inject your insulin, especially around exercise.

Diabetes, exercise and foot care#

People who have had diabetes for a long time, or who have consistently high BGLs, are at higher risk of developing foot problems. If you have nerve damage to your feet (called peripheral neuropathy), you are more prone to injury and to problems such as foot ulcers.

You can prevent foot injuries and infections by:

• wearing well-fitting socks and shoes – check that shoes are long enough, wide enough and deep enough
• wearing the right shoe for the activity you are doing
• inspecting your feet daily
• reporting any changes to your feet, such as redness, swelling, cuts or wounds, to your doctor as soon as you notice them
• having your feet checked regularly, including an annual foot check

Diabetes, exercise and blood glucose levels#

Exercise causes your muscles to use more glucose, so it can lower your BGLs. It is important to keep track of your BGLs before, during and after exercise.

Hypoglycemia#

Hypoglycemia (a BGL of 4.0 mmol/L or less) can occur in people who inject insulin or take a glucose-lowering medication such as a sulphonylurea. Because exercise makes your muscles use more glucose, people taking insulin or tablets that make you produce more insulin are at risk of their BGLs going too low.

Check your BGLs before, during and after exercise to see how the activity affects you. The type, duration, intensity of exercise and your fitness level can all have an effect.

You can reduce your risk of hypoglycemia during and after exercise by:

• increasing your carbohydrate intake as needed, according to the intensity, duration and type of exercise
• decreasing medication or insulin as needed, after talking to your doctor
• checking your BGL before exercise – make sure it is at least 7.0 mmol/L
• checking your BGL regularly during and after exercise

Your risk of hypoglycemia during exercise is higher if you:

• have type 1 diabetes
• inject insulin or take a sulphonylurea
• have had recurring episodes of hypoglycemia
• have an episode of hypoglycemia before exercise (both exercise and a recent hypo reduce your ability to detect further hypoglycemia)
• are unable to detect the early warning signs of hypoglycemia
• have drunk alcohol (alcohol reduces your ability to detect hypoglycemia)

Always carry easy-to-use hypoglycemia treatments with you if you are at risk of hypos, such as jelly beans or glucose gel, and consider wearing a medical alert bracelet.

Hyperglycemia#

Hyperglycemia means BGLs are too high (over 11 mmol/L). Exercising when your blood glucose is higher than normal can lower your levels. However, if you are unwell and your BGLs are very high, it is best to avoid exercising until your BGLs have returned to the normal range.

People with diabetes who have BGLs above the normal range are more at risk of dehydration, so increase your fluids to stay hydrated when you exercise.

Diabetes, exercise and ketoacidosis#

People with type 1 diabetes are at risk of developing a build-up of ketones (ketoacidosis). If you have type 1 diabetes and you are unwell, avoid exercise until you feel better.

If your BGL is above 15 mmol/L and you have positive blood or urine ketones, you need to clear the ketones from your blood before beginning exercise. Extra insulin is needed to clear ketones, so ask your diabetes health professional for an individual management plan.

People with type 2 diabetes are generally not at risk of developing dangerous levels of ketones (unless taking an SGLT-2 inhibitor) and therefore do not usually need to check for them.

Diabetes complications and exercise#

If you have existing diabetes complications such as heart, eye or kidney problems, check with your diabetes specialist whether it is safe to do certain types of activity. They can advise you which types of exercise to avoid in order to prevent worsening complications.

Key points#

• Regular exercise has benefits for everyone, including people with diabetes, especially when combined with healthy eating.
• Have a health check with your doctor and an individualized diabetes management plan before starting a new exercise program.
• People with type 1 diabetes, and those using insulin or sulphonylureas, are at risk of hypoglycemia during and after exercise.
• Check your BGLs before, during and after exercise, and look after your feet.
• People with type 1 diabetes should avoid exercise when unwell or when ketones are present until ketones are cleared.

Where to get help and trusted information#

For evidence-based global health guidance, see Source: World Health Organization (WHO).