Type 1 Diabetes and Exercise

Web Resource Last Updated: 09-05-2024


Below you will find some tips on exercise with type 1 diabetes.  For more information on managing type 1 diabetes with exercise, please register for our FREE online course, 'Type 1 Diabetes and Physical Activity'.

Why exercise is good for us?

Almost everyone benefits from exercise, and if you have type 1 diabetes, there are some additional ways that maintaining an active lifestyle will be good for you:


Exercise can help improve your blood glucose control and if you stick at it, it can bring your HbA1c down.



Exercise can increase how sensitive your body is to insulin and in time might mean that you need less insulin.  



When you exercise you burn through the available glucose in your bloodstream, lowering your blood glucose level.



Exercise can help control your weight.  



In the long term, exercise can reduce your risk of cardiovascular problems such as heart disease or high blood pressure. 


Exercise can make you feel better and happier. When you exercise, your body releases endorphins, which work with your brain to lift your mood and minimise pain. People who exercise regularly talk of the "natural high" they get from it. The hard part is to actually get out and do it in the first place!



People with type 1 diabetes have excelled at all levels in a huge variety of sports. Runsweet.com is a great resource showing the range and experience of sports that people with diabetes have undertaken. 


How do I get started?

If you are new to exercise, it is generally best to start slowly and build up the duration and intensity of exercise over time.

There are lots of ways to increase your physical activity. You don’t have to go to the gym, jog/run or join a club although exercising with others can keep up your motivation.  Free apps like couch to 5k may help you get started and many people have found that their local Parkrun is a great way to meet up with others once a week and stay motivated once you have built up to the 5km distance.  

Exercising at home is increasingly popular.  You don’t need specialist equipment and you can find free fitness programmes like Couch to Fitness online that cater to all ages and levels of fitness. 

Keeping going

Goal setting

Setting yourself goals that are realistic and achievable can help keep you going. It is also worth thinking about the amount of time you feel it will take to achieve your goals.

Action plan

Making a plan helps with setting clear goals. Things to consider are:

  • What sort of exercise are you going to do?
  • How often are you going to exercise?
  • How long will you exercise?
  • How intensely will you exercise?

Keeping a record

Recording the exercise that you have done can be really motivating to keep going. There are lots of ways of doing that including:

  • Exercise diary or Training log – a simple paper record in a diary or notebook is an easy way to look back over what you have achieved.
  • Wearable technology e.g. FitBits, Garmin watches record your activity and show you how you are getting on.
  • Online diaries or training logs (e.g. myfitnesspal) provide digital records of your activity that are easy to review


Is it safe for me to exercise?

For most people with type 1 diabetes, it is perfectly safe to exercise.

Many people worry that exercise will cause low blood sugars (hypoglycaemia) or generally make their diabetes more difficult to control. However, by following some of the simple principles below, you can make sure that the risk of hypoglycaemia or variable blood sugars is very small.

There are some specific conditions where you need to be cautious or action needs to be taken before starting any exercise:

Plan your exercise

Although not always possible, it is easier to keep control of blood sugars if exercise is planned in advance.

Before Exercising

Before you exercise, you should think about:

  1. What exercise you are going to do, how hard you are going to work and for how long?
    Aerobic activities (e.g. cardio training) tend to send blood sugar levels low, whereas anaerobic activities (e.g. weight training) can push blood sugars up.
  2. What time of day you are going to exercise?
    Many people find that diabetes is easier to control if exercising first thing in the morning.
  3. What are your glucose levels doing?
    The flowchart below provides guidance on what to do depending on your glucose level before you are about to exercise.  DO NOT EXERCISE IF YOU HAVE HAD A SEVERE HYPO IN THE 24 HOURS BEFORE YOU ARE PLANNING TO EXERCISE.  A severe hypo is one where you have needed help from someone else to sort it out.

If you have had a self-treated hypo in the last 24 hours:

  • Do NOT exercise alone
  • Check your blood sugar more often
  • Check your blood sugar during the night after your exercise


During exercise

You have 3 options to help keep your blood sugars controlled during exercise:

1. Reduce your insulin prior to exercise – a good starting point is a 50% reduction if exercising less than 2 hours after a meal.


2. Take on additional carbohydrates during exercise - 30-60g of quick-acting (high GI) carbohydrate (eg 6-12 large jelly babies) per hour of exercise is a good place to start.


3. Alter the order of exercise if you are doing mixed activities - If you are doing a mixture of activities you can change the order depending on your starting glucose:

  • If your pre-exercise glucose is a bit high, start with aerobic activity.
  • If your pre-exercise glucose is at the lower end, start with anaerobic activity.

After exercise


REDUCE insulin after Exercise

A good place to start is with the “50/50/20” rule:

  • 50% REDUCTION in quick-acting (bolus) insulin for the TWO meals after exercise
  • 50% REDUCTION in correction doses for 12 hours after exercise
  • 20% REDUCTION in background (basal) insulin if:
    • Exercising after 4 pm
    • Over 2 hours of exercise
    • High-intensity interval training (HIIT) at any time of the day

Carbohydrate (and fluid)


If you have done more than 60 minutes of moderate-intensity exercise or more than 30 minutes of high-intensity exercise,
“re-fuel” with additional carbohydrate AND protein (e.g. milkshakes and/or cereals).

Bedtime snack

Consider having a bedtime snack if:

  • You exercised after 4pm
  • You completed more than 2 hours of exercise

Hydration / Rehydration

it is important to keep hydrated. You should drink about half a litre of fluid per hour of exercise.

When should you check your blood sugar?

The only way to know the effect of exercise on your blood sugars is to check your blood glucose. Blood glucose should be checked at 3 time points:

  • Before exercise - two blood glucose readings should be taken at least 10 minutes apart before exercise so that the starting glucose is known as well as the direction in which the blood glucose is going.
  • During exercise– if possible blood glucose levels should be checked every 30 minutes during exercise.
  • After exercise – blood glucose levels should be checked on finishing, an hour later and 6 hours later (or before going to bed). If you have done a new exercise or exercised for longer than 2 hours then you should check your blood glucose level at 3 am.

Useful Resources

For more information on managing type 1 diabetes with exercise please register for our FREE 'Type 1 Diabetes and Physical Activity' online course.

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