How to take the risk out of exercise

Thursday, 2 December 2021

Exercise and type 1 diabetes management go hand-in-hand. We know how important regular physical activity is in the management of both short- and long-term blood glucose control. It’s equally important to remember that exercise does come with risk.

Without proper precautions and planning in place, exercise can possibly lead to large fluctuations in blood glucose, injury, or could impact any existing complications.

Exercise and risk

How can we manage this risk and get the most out of physical activity?

The answer is to form an exercise safety plan. But what does an exercise safety plan look like? Where can you find one?

This article outlines what precautions to take with exercise and type 1 diabetes. It also discusses how to develop a plan to reduce the risk of any complications.

To develop an exercise safety plan, we first need to understand the main safety concerns, listed below, that surround exercise.

Safe blood glucose levels and fluctuations

The great variable in exercise and diabetes is the changes in your blood glucose over time. Exercise can result in a decrease in your blood glucose readings both in the short- and long-term. However, not all exercises will cause a reduction immediately.

Lower intensity aerobic (cardio) exercises like walking or gentle cycling cause an immediate reduction in your blood glucose, by using the extra glucose that’s floating in the blood as energy.

Higher intensity exercises like sprinting, interval training, or heavy weight training can actually cause short term increases in your blood glucose.

Your body will respond to the intensity of the exercise and stimulate the release of hormones that support energy demands.

This energy demand will see more glucose released into the blood, from storage houses like the liver.

Improvements to insulin sensitivity

Both types of exercise will lead to improvements in your body’s sensitivity to insulin and ability to absorb, store, and use glucose in the hours that follow, resulting in improvements in diabetes management over time.

Understanding this is the first step in ensuring you are within safe ranges to complete exercise.

In type 1 diabetes, it is recommended to sit within a range of 7-15mmol/L to complete exercise safely.

This ensures you minimise the risk of hypoglycaemia (which we’ll discuss shortly) along with any unwanted increases in your glucose levels.

Understanding the aforementioned information can also assist in ensuring you stay within those ranges throughout your session.

For example, if you’re on the lower end, try starting your exercise session with higher intensity exercises. If you’re on the higher end, try lower intensity cardio.

If you’re unsure of what is and isn’t safe at different blood glucose levels, you can refer to the following action plan developed by Exercise Is Medicine.

Hypoglycaemia and delayed hypo

As we know, exercise can cause immediate reductions in your blood glucose, which is why it’s important to stay within a safe range when exercising.

One of the great benefits of exercise is that this glucose-lowering effect can last for several hours after your exercise session.

With that, however, comes the potential risk of Delayed Onset Hypoglycaemia.

This long-lasting reduction, if not paired with adequate consumption of carbohydrates or potential adjustments in insulin dosages, can result in unwanted drops in blood glucose levels if the appropriate precautions aren’t met.

Check before changing

Consult with your GP, Endocrinologist, Credentialled Diabetes Educator, or Pharmacist regarding any changes to your physical activity routine and possible adjustments in insulin dosages or timing.

Often this stage is experimental and success is reached through trial and error.

As a result, it can be frustrating. It may involve more frequent blood glucose checks or stop-start types of activity. Try to take your time to really understand the changes in your blood glucose due to exercise and how best to manage this.

You might also wish to discuss your energy intake with an Accredited Practising Dietitian. You may also wish to consult with an Accredited Exercise Physiologist on strategies to prevent the onset of hypoglycaemia.

Avoid further spikes when high

It’s important to remember to avoid spikes in blood glucose levels when they may already be high.

This could result in the presence of ketones in the blood, and if the appropriate steps aren’t taken, can lead to possible complications in health such as diabetic ketoacidosis (DKA).

As a general rule, try not to engage in exercises that increase blood glucose levels if your current glucose levels are high.

Consult with the Exercise Is Medicine type 1 diabetes exercise action plan for information on specific ranges and actions.

Food, food, food!

When it comes to managing your blood glucose during exercise, food is your friend.

Carbohydrates are broken down in the stomach and small intestine, then converted to glucose for energy. When you’re physically active, you may want to consider consuming extra carbohydrate-based snacks 1-3 hours before your workout. They will boost your energy and prevent your blood glucose dropping too low.

Snack ideas include slow-acting (low GI) carbohydrates like fruit or a muesli bar.

You’ll also want to keep some food on you during your workout – what we refer to as a hypo kit.

Monitor BGLs

Monitor your blood glucose levels consistently throughout the session. If your blood glucose drops or falls outside of the safe range, consume a fast-acting (high GI) carbohydrate snack. Examples are six to seven jelly beans, glucose tablets, or half of a juice box.

Once it returns to safe ranges, consume a slow-acting carbohydrate snack like a muesli bar, slice of wholegrain bread, or yogurt.

Finally, consider your food intake after you exercise. As discussed, your body will be more effective at absorbing insulin after your session. Consider frequently monitoring your blood glucose and keeping some extra snacks on hand to prevent any lows.

Consuming a low GI snack before bed, and possibly checking your blood glucose readings at 2-3am is recommended to understand how your body is responding to exercise. It will reduce the risk of nocturnal hypoglycaemia (an over-night hypo).


Diabetes can often come with complications to your health. This can include, but is not limited to, damage to your feet, peripheral neuropathy, or restricted blood flow to your extremities. Diabetes-associated complications come with some extra considerations to ensure your safety.

Ensure your exercise space is safe, and free from any trip hazards. Always wear enclosed shoes to protect your feet. Some types of exercise aren’t suitable for people who experience complications of diabetes. If you do experience some form of complication or you’re not sure whether exercise is right for you, consider consulting with your doctor or an Accredited Exercise Physiologist before starting to exercise.

Minimise risk of injury

Lastly, we want to ensure that you come out of your exercise session feeling energised and ready for the next one.

To do this, we need to minimise the risk of injury.

Stick with what you know, and look for guidance when trying something new. Pick intensities or resistance levels that are challenging, but not to the point that you can’t complete it confidently. Know your limits and listen to your body.

To minimise injury, it’s best to start at a level that suits you. If you’ve never exercised before and are unsure of where to start, try something simple like walking or cycling, or consult with an Accredited Exercise Physiologist for guidance.

Using these key points, you can develop an exercise plan that gets you from start to finish with your safety at the forefront!

Refer to resources

If you’re still feeling unsure about your safety plan or if you have questions, there are a few great resources available.

You can find a blood glucose action plan developed by Exercise is Medicine, outlining what steps to take and exercises to consider or avoid depending on your blood glucose reading before exercise.

You can also call the NDSS Helpline (1800 637 700) to speak with an Accredited Exercise Physiologist. They can discuss exercise safety with you, and assist in perfecting your plan.

Free exercise program for people living with diabetes

Finally, for a more hands-on experience, NDSS Registrants have access to the Beat It Program. This NDSS initiative is a free, 8-week physical activity and lifestyle education program. It’s available face-to-face and online.

It’s designed to kick-start your physical activity journey and empower you to exercise safely and independently.

If you have any other questions or concerns, consult with your healthcare team or reach out to an Accredited Exercise Physiologist, Credentialled Diabetes Educator, or Accredited Practising Dietitian via the NDSS Helpline on 1800 637 700.

By Jonathon Fermanis
Accredited Exercise Physiologist

Join our community of over 45,000 people living with diabetes