Pump users

Pump users

One of the attractions of insulin pumps is the flexibility they allow, particularly around exercise. Generally, the things to think about are similar whether you are on injections or a pump.

Before exercise

Bolus insulin

If you do aerobic exercise less than 90 minutes after a meal:

  • Reduce bolus insulin by 25 – 75%
  • A 50% reduction is a good place to start
  • You can vary the reduction depending on the intensity and duration of exercise

For further guidance about how much to reduce bolus insulin depending on the intensity and duration of exercise, see the table below:

Table with columns showing exercise intensity and duration of 30 or 60 mins

For mild aerobic activity, reduce bolus by 25% for 30 mins and 50% for 60 mins

Moderate aerobic, reduce bolus by 50% for 30 mins and 75% for 60 mins

Heavy aerobic, reduce bolus by 75% and 50% for 60 mins

Basal insulin

The amount you reduce the basal rate by depends on the intensity and duration of the exercise and varies from individual to individual. General advice would be to:

  • Reduce basal insulin 60-90 minutes prior to activity and during activity
  • Reduce by 50 – 80%
  • 50% reduction is a good place to start

Note – if you are doing short periods of anaerobic activity, you don’t need to make any changes to your basal or bolus insulin.

During exercise

The best strategy is either/or (as per MDI) REDUCED BASAL RATE (following the guidance above), taking EXTRA CARBOHYDRATE.

  • You should aim to take 0.25g to 0.5g of carbohydrate per kilogram body weight per hour
  • It is best not to take all the carbohydrates in one go, but to take some extra carbohydrates every 20 minutes during exercise

To calculate the number of carbohydrates you should take per hour during exercise you can do the following calculation:

How to calculate grams per hour of carbs during exercise:

weight in kilograms x minimum carb intake = carbs g per hour

For a 70kg person:

70kg x 0.25g = 17.5g/hour

After exercise

Bolus insulin

It’s a good idea to reduce your bolus insulin after exercise and keep monitoring your blood glucose levels to try and keep your blood glucose levels stable. General guidance is to:

  • 50% reduction in boluses for the two meals after exercise, for example, if you exercise in the afternoon, reduce your quick-acting insulin with both your evening meal and your breakfast the following day
  • 50% reduction in correction boluses for 12 hours after exercise

Basal insulin

At the end of your activity, return to your normal basal rate. At bedtime, you can reduce it by 20% if you:

  • Have exercised after 4 pm
  • Completed over 2 hours of exercise
  • Did a High-intensity interval training (HIIT) workout at any time of the day
  • Took part in a new form of exercise for you

Putting it all together

The following examples illustrate how you can put the above advice into practice. These are places to start and you may well need to make changes based on your experience. Your diabetes team can support you if you need any further advice.

Morning exercise

If you do your usual exercise in the morning and exercise for less than 2 hours:

Bolus insulin

Basal insulin

Afternoon/Evening exercise

If you exercise after 4 pm but before your evening meal:

Bolus insulin

Basal insulin

General tips

Pre-exercise hyperglycaemia

Some people find that their blood glucose level runs high just before exercise. This is particularly true before competitive matches or big events. There are a number of ways you can manage your blood glucose levels if this is the case:

  • Drink plenty of water: good hydration will help with reducing blood glucose levels
  • Low-intensity warm-up: doing some low-intensity aerobic exercise will help to control glucose levels
  • Correction boluses:
    • Use with caution as there is a risk of hypoglycaemia once you start exercising
    • Reduce your correction bolus by 70%
    • Don’t give more than one correction as the insulin will stack up

Pump removal

Generally, it is better to keep the pump on and reduce the insulin as above rather than taking the pump off altogether when you do exercise. However, there are some sports (e.g. watersports, contact sports, martial arts) for which you will have to take the pump off.

If you do have to remove your insulin pump then:

  • Don’t remove the pump for more than 1 hour
  • Missed basal insulin (i.e. the basal insulin that you would have had during the time the pump is off) can be given as a bolus dose either before activity if you are doing an anaerobic activity, or after putting the pump back on if you are doing aerobic exercise.

Be aware that if you have done aerobic activity, you will need to reduce the bolus:

  • Calculate the amount of basal insulin you would have had during the activity
  • Reduce that amount by 50 – 80%
  • Give the amount as a bolus dose

Example: If you would have had 4 units of basal insulin during the activity, give a bolus of 2 – 3 units at the end (50 – 80% of 4 units).

Closed loop systems

If you use a closed loop system you can find some helpful advice on the beyondtype1 website.


  1. Comment by alex- 82 on 28/07/2022 at 11:24 AM

    “The best strategy is a combination of REDUCED BASAL RATE (following the guidance above) and taking EXTRA CARBOHYDRATE” – this is what I put in the first draft, but then I changed it to either / or (as per MDI) when I contacted the EXTOD people

    It was really confusing because when I watched the EXTOD webinar they said do both which is why I contacted them for clarification.

  2. Comment by alex- 82 on 28/07/2022 at 11:25 AM

    Typo – “Some people find that their blood glucose levels runs high just before exercise” should be “Some people find that their blood glucose level runs high just before exercise”

  3. Comment by alex- 82 on 28/07/2022 at 11:26 AM

    Typo – “Don’t remove oy for more than 1 hour” should be “Don’t remove the pump for more than 1 hour”

  4. Comment by alex- 82 on 28/07/2022 at 11:27 AM

    Typo – “…as a bolus dose eithe before activity… ” should be “…as a bolus dose either before activity, …”

  5. Comment by Kirsten. C. on 01/08/2022 at 11:44 AM

    Fixed all typos

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