Information alert

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To manage activity and sports it is good to know what usually happens to your glucose levels to help you plan. Remember different types of activities can have different effects on your glucose levels. There is a feature on your pump called Exercise Activity that is designed to help you prevent low glucose levels (hypos) when you are being active.

  • Sprint, strength and power sports usually make glucose levels rise. they are all anaerobic activities.
  • Running, swimming, cycling and walking are all activities that usually lower glucose levels. They are aerobic activities.
  • Team sports may cause glucose levels to rise or fall as they are mixed activity.
  • Training usually lowers glucose levels, matches and competition will push glucose levels up.

Watch this video about how exercise and activity lowers glucose levels during and after sports.

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Being active can mean everyday activities like walking to school, playing football in the park, going shopping or it can be planned sports and exercise.

The Tandem T Slim pump with Control IQ is a hybrid closed loop system that makes adjustments to your insulin delivery based on your glucose levels.

For sports, activities and exercise that usually lower glucose levels (aerobic activities) use the ‘exercise activity’ setting on the pump. This will raise the glucose target and change the alert level for a low glucose level.

We recommend starting exercise with a glucose level between 5-10mmol/L, using the exercise activity setting will help to keep the glucose level at the higher end of the target range to avoid low glucose (hypo) during exercise.

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If you are going to have a meal with insulin in the two hours before exercise, switch to exercise activity mode before you eat.
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To manage activity, you need to check your pump to help you to know what you need to do. sometimes you will need to help the pump prevent low or high glucose levels during sports/activity. If the pump has already suspended insulin then you will need snacks to prevent low glucose levels.

Below is a reminder of the pump icons.

Control-IQ Technology Pump Icons

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Try and switch to the exercise activity setting 60-90 minutes before any sports or exercise that usually lower your glucose levels during the exercise.

Before exercise and sports

  • With exercise activity on, you will get a low glucose alert when your glucose is predicted to hit 4.4mmol/L in the next 30minutes, take a hypo treatment before starting activity if you have a low glucose alert.

Use this link to watch a video on the Exercise Activity feature.

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*When an Exercise Activity is enabled

Check your glucose level, your sensor arrow and the pump insulin delivery at the start and during activity.

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Using exercise snacks

Extra carbohydrate snacks can be used to help prevent low glucose levels during activity/sports. The amount of carbohydrate needs to be carefully monitored. If extra carbohydrate starts to push the glucose level up so it is predicted to rise above 8.9mmol/L the system will start to increase the basal insulin delivery.

We recommend using smaller exercise snacks through activity if you need them. Use your sensor arrows as a guide.

  • Lower glucose levels and falling glucose usually means you will need to snack.
  • Higher glucose levels and rising glucose levels usually mean you won’t need snacks.
  • Remember to check to see if your pump has suspended – if your glucose levels are falling and the pump is suspended you will need a bigger exercise snack. You can use the table below as a starting guide.

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When to stop exercise activity setting

You can switch off the exercise activity setting at the end of exercise or leave it on, depending on your usual glucose responses to the sports.

If your glucose levels usually fall after the activity leave the exercise setting on. If your levels usually go up after being active switch it off.

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Remember that you cannot use the ‘sleep’ function if exercise activity is running so if your sport is at the end of the day remember to switch the exercise activity off before bed.

Reducing the insulin bolus with the pre-exercise meal

Big reductions in your insulin dose with meals before exercise may cause your glucose levels to start to rise after eating. If this happens then the system will start to increase your insulin. This can cause hypos. Only make small reductions to mealtime insulin before exercise.

If you need to reduce insulin with your meal try using 20 - 25% less insulin (reduce by one fifth or one quarter, you can do this by entering fewer carbs into the pump).

If you are eating a meal in the hour before exercise reduce your food bolus and start exercise activity before the meal.

If you are eating between 90 minutes and two hours before activity, try the exercise activity setting before the meal. This will change the glucose target after the meal and help to Reduce hypo risk during exercise.

Using additional pump profiles

Control IQ uses the programmed basal rate in the pump. This means that you can use different basal profiles to lower insulin delivery.

For very active days try setting up lower basal profile with 30 - 50% less basal insulin and reduce carb ratios and insulin sensitivity by 50%.

Stop the system giving automatic correction boluses

If automatic correction boluses during exercise cause hypos you can stop them by giving a 0.05 unit manual correction 15 - 45 minutes before activity. The system will not give an automatic correction bolus for the next 60 minutes.

Managing exercise that causes high glucose levels

For sports and exercise that usually increase glucose levels, you may not need to use the exercise activity setting during the sport. If your sport causes high glucose levels that are not managed by basal adjustments and automatic corrections you may need a different pump profile that gives more insulin during the exercise. Exercise activity setting may be needed after sports that usually push glucose levels up to help prevent hypoglycaemia after exercise.

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High glucose levels at the end of exercise can be helped by doing a 'cool down' 15 minutes of gentle aerobic activity that will lower glucose levels.


Managing sports with the pump off

For some activities you will need to remove your pump.

It is important that you stop Control IQ if the pump is off during exercise.

You can still use the exercise activity setting in the hour before the sport to help you start at the higher end of your glucose target range and reduce the amount of insulin in the body when the exercise begins.

  • If you leave the pump running this will affect the insulin delivery when the pump is reconnected.
  • If the pump needs to be stopped for longer than 30minutes, toggle Control IQ off and then stop the pump, this will stop the pump alarming after 30minutes.
  • Remember to toggle Control IQ on as soon as you reconnect and restart the pump.

If the pump is off for exercise/sports use the Dexcom trend arrows to guide when to and how much extra carbohydrate to take.

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When you reconnect the pump, if your glucose levels are in range and falling/stable or you are worried about post exercise low glucose levels you can use the exercise setting to aim for a higher glucose target.

Some sports with the pump off can cause high glucose levels. If this happens put the pump back on at the end of the sport and do a 15-minute cool down to help lower your glucose levels. Using a cool down will help glucose move into the muscles.

Understanding 'the cool down'

When we exercise we have to make ATP for our muscles to work. As well as ATP we produce lactate or lactic acid which we need to get rid of at the end of exercise. Lactate can cause sore and stiff muscles. If we do a cool down the lactate will be removed from the body. Without a cool down the liver gets rid of lactate by converting into glucose which then enters the blood causing high glucose levels.

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Lactate converted to glucose in the liver through the Cori cycle.

Different exercise types will have different impacts on your glucose levels. You may need to try different ways of managing diabetes for different types of activity. One way to learn about your glucose responses to exercise and what works for you is to keep an activity diary. Sometimes you will need to try a few different strategies to find what works.

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When an activity is new it is more likely to lower your glucose levels.

The weather can change your glucose responses to exercise if it is very hot or cold.

When you are being competitive you are more likely to have high glucose levels than low levels.

When you are doing a fitness session you are more likely to have low glucose levels. Activities like climbing, high ropes courses or anything that causes a bit of fear or excitement may push your glucose levels up a bit because you are making adrenaline.

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Contact us for help and advice managing activity and exercise.

You can email us for advice or you can book into an exercise and diabetes clinic. The clinic takes place on a Friday morning and we have virtual and in person clinics.

If you would like an appointment send us an email or ask when you are in clinic. You will find general information about managing activity and diabetes at

My exercise management plan