Exercise and type 1 diabetes

What is the difference between physical activity and exercise?

Physical activity is any movement that you do that uses energy. This doesn’t have to just be a sport or organised exercise, it can be anything from mowing the lawn, doing the vacuuming or running for the bus. These activities all take up energy and will have an impact on your blood glucose levels.

Exercise is a type of physical activity that is planned and structured and can be focused on improving an aspect of your fitness. This can be joining a football, netball or rugby team, working out at the gym or training for a marathon.

Managing type 1 around physical activity

We often don’t realise we’re doing physical activity when we’re doing our day-to-day tasks, but it’s important to remember that any sort of physical exertion may affect your blood glucose levels. If you’re doing something more strenuous than usual – like gardening, climbing stairs or lifting lots of heavy boxes – make sure you check your glucose levels more often to make sure you’re not going too high or too low.

Can people with type 1 do exercise?

Yes. Adjusting food and insulin around exercise can be a challenge because different types of exercise can have a different effect on your blood glucose levels. Some exercise can cause your blood glucose level to go low, and other exercise can cause it to rise.

This doesn’t mean you shouldn’t do exercise or physical activity, but you will need a plan to help manage your blood glucose levels around the activity you want to do. Speak to your Diabetes Healthcare Team about putting a plan in place.

What are the benefits of exercise if you have type 1 diabetes?

Exercise and fitness is good for everybody, but if you have type 1 you will see some extra benefits. Exercise can help keep your blood glucose levels more stable in the long term and can increase your sensitively to insulin, meaning you might not always need to take as much.

Being active can also help prevent long-term type 1 complications, particularly heart disease. You will also gain the same benefits from exercise as someone without type 1 would, like lower blood pressure, more energy and stronger muscles and bones – not to mention a nice release of mood-boosting endorphins which can help your mental health.

What’s the best exercise if you have type 1 diabetes?

There is no right or wrong exercise to choose, so pick something you enjoy. What’s important is to learn how the exercise you want to do affects your blood glucose levels.

How does exercise affect blood glucose levels?

Exercise affects everyone with type 1 differently, which is why it’s important to work with your Diabetes Healthcare Team on a plan that is personal to you.

However, there are general ways your blood glucose levels are affected by exercise.

• Flexibility exercise like yoga, tai-chi and pilates will have a minimal effect on your blood glucose levels. This is because only a small amount of glucose is released from the liver and only a small amount is used by the muscles
• Aerobic exercise like swimming, cycling or running may have a varied impact on your blood glucose levels but is likely to cause them to drop
• Anaerobic exercise like sprinting and weightlifting, is likely to cause your blood glucose levels to rise. This is because your body releases high levels of adrenalin that trigger your liver to break down stored glucose and release it into your bloodstream.

Managing your blood sugar levels before, during and after exercise

Before exercise

Test your blood glucose level before you exercise. This will help you decide if you need to eat any carbohydrate before you start your activity. How much carbohydrate you might need to consume also depends on the types of exercise you plan to do, the intensity of it and how long you plan to exercise for.

Should you take insulin before you exercise?

If your blood glucose levels are high and the exercise you’re doing may cause them to rise, you may need to take some insulin before you exercise. You should discuss this with your Diabetes Healthcare Team.

During exercise

If you are exercising intensely or over an extended period of time, you’re likely to need extra carbohydrate during exercise. Less carbohydrate is required the longer it was since your last insulin injection.

If you can, check your levels every 20 – 30 minutes during exercise.

After you exercise

Check your blood glucose as soon as you finish exercising and then every few hours after that.

Up to six hours after exercise

If your blood glucose level is normal to low immediately after exercise, you may need to eat some carbohydrate as your blood glucose levels may continue to slowly drop. You may also like to consider eating a low GI food (food that releases carbs slowly, like oats, beans, pulses, wholegrain pasta or bread) to help keep your blood glucoses levels up in the hours after your exercise. If your blood glucose levels have risen during exercise and you took the right amount of insulin before you started, they should be back to your pre-exercise level within three to six hours.

Around 8-12 hours after exercising your blood glucose level could drop too low

This is because your adrenalin levels drop, and your muscles and liver will start to use extra glucose to replace what you burned during exercise. You will need to take this into account when estimating your insulin dose prior to, or immediately after, exercise.

Exercising late in the day

If you exercise in the late evening after dinner, it may increase the risk of a hypo overnight, often around 2-3am. To reduce the risk of this, you might need to take less evening insulin or eat a low GI snack before bed. If you use an insulin pump, reducing the basal rate can help. Talk to your Diabetes Healthcare Team about how to manage this.

Learning how exercise affects you

Managing type 1 around exercise can be a little bit trial and error, so it’s good to keep a log of what exercise you’re doing and how has affected your glucose levels. You can take this information to your Diabetes Healthcare Team so they can help you come up with a plan.

Can type 1 diabetes technology help you manage type 1 with exercise?

Using technology that can quickly give you a glucose reading, like a continuous glucose monitor or flash glucose monitor, can be easier than doing a finger prick test with a blood glucose meter.