10. Exercise and Diabetes

Exercise and Diabetes

Keeping active is an important part of a healthy lifestyle for all children, including children and young people with diabetes. After a new diagnosis of diabetes, children are able to return to usual sports and activities once blood glucose levels have stabilised and families have learnt about managing diabetes and sports and other physical activities.

Low blood glucose levels and exercise

Increased activity levels can reduce blood glucose levels. This happens because the muscles used during exercise need more glucose for energy but also because exercising can make the body more sensitive to the effects of insulin (i.e. the same dose of insulin works more effectively).

Hypoglycaemia, or a low blood glucose level, can happen during exercise but can also happen after exercise has occurred, sometimes up to 12-24 hours later.

High blood glucose levels and exercise

Sometimes exercise can make the glucose levels rise. This can happen during or soon after exercising. This is most often related to excitement or nervousness around competitive sports that leads to a surge of adrenaline and other hormones that increase the amount of glucose being released from the liver. These high glucose levels will generally fall without any intervention.

Exercise and illness

It is important that children with diabetes do not participate in exercise if unwell, as exercise can result in raised blood glucose levels,.

If blood glucose levels are above 15mmol/L before exercising, it is recommended that a test for ketones is undertaken. If blood or urine ketones are present (see module on sick day management), exercise is not recommended.

Monitoring and exercise

Testing the blood glucose levels more frequently (before, during and after sporting or social activities) is essential to establish an understanding of how different types of exercise affect the blood glucose levels. Every child responds differently to exercise. The diabetes team work together with families to establish individualised exercise plans based on accurate records of blood glucose levels around specific sports activities.

You can read a transcript of this video here.

It is important that children with diabetes are supervised during exercise or undertake exercise with an adult that is diabetes-aware and has the knowledge of how to manage hypoglycaemia.

It is important that children with diabetes have access to hypoglycaemia treatment during exercise.

Because hypoglycaemia can happen for up to 24hours following significant exercising it is a good idea in addition to undertaking regular daytime blood glucose testing to undertake an additional blood glucose test in the late evening (10-11pm) and overnight (1-3am) on days where activity levels have been high.

Adjusting diabetes management for exercise

Most sporting activities lasting more than 30minutes will need some adjustment to the usual doses of insulin and the usual amounts of food eaten. The type of adjustments will depend on many things such as, usual activity levels, the level of exercise intensity, the type of insulin regimen being used and whether or not the exercise is planned or unplanned.

Adjustments for exercise might include:

  • Reducing the dose of insulin that is working during the period of exercise

  • Reducing the dose of insulin that falls after the period of exercise

  • Additional carbohydrate before and sometimes during exercise

  • A combination of both reductions to insulin doses and additional carbohydrates

For younger children where activity levels are unpredictable (i.e. at preschool) and unplanned; additional carbohydrate will be the easiest way to manage blood glucose levels and prevent hypoglycaemia.

For older children where exercise is scheduled, plans to make reductions to insulin doses and/or additional carbohydrate to prevent hypoglycaemia can be discussed in advance with the diabetes team. Many older children prefer to adjust insulin in preference to taking additional carbohydrate to avoid increased food or drinks before sport which may cause a "stitch" or as part of a healthy weight management plan.

The amount of additional carbohydrate taken before and sometimes during exercise will vary between children and will be related to individual response to exercise. When children with diabetes are first diagnosed it is generally recommended that for every 30minutes of moderate intensity exercise (i.e. swimming, soccer, basketball, rugby etc) an additional carbohydrate snack (approximately 15gms) is taken prior to the activity. If the carbohydrate snack is "fast-acting" carbohydrate such as juice, this needs to be taken immediately before exercise. If the carbohydrate snack is more "long-acting" such as a banana or museli bar, this will need to be taken 20-30minutes before exercise.

In older children (teenagers) 1-1.5grams of carbohydrate per kg of body weight can be taken each hour during strenuous exercise or long duration exercise where pre-exercise insulin has not been reduced.

It is important that children with diabetes also have adequate carbohydrate intake at the scheduled meal or snack after exercising.

During exercise children should be drinking water. In most cases sports drinks (i.e. Powerade, Gatorade etc) are not required unless they are part of an individualised sports plan provided by your diabetes team.

Let's go over the main points. Read this factsheet to make sure you understand the main points about diabetes and exercise.

Think you've got it sorted now?

If you and your parent/carer have read through the information above and watched the videos, and you feel confident that you understand this topic, print off and fill in the evaluation form below (you might need to ask someone to print this off for you) and return to the nurse on your ward. If you have any questions, note them down on this form and your diabetes nurse specialist will discuss them with you.

Exercise and Diabetes: Evaluation

After reading this module, I:

Understand that exercise is an essential part of a healthy lifestyle for all children including those children with diabetes  
Understand the importance of monitoring the blood glucose levels before, during and after exercise  
Understand that blood glucose levels can go down with exercise but can also rise for a short period  
Understand that reductions to insulin doses and/ or additional carbohydrate may be part of an individualised exercise plan  
Understand that delayed hypoglycaemia can occur up to 24hours following exercise  
Understand that if the blood glucose levels are above 15mmol/L and ketones are present that it is dangerous to exercise