Type 1 diabetes

Advice on carbs and insulin to reduce hypo risk during exercise

A new position statement highlights the complexity of glucose management for exercise in people with type 1 diabetes using CGM and intermittently scanned CGM (isCGM).

The statement, from the European Association for the Study of Diabetes (EASD) and the International Society for Pediatric and Adolescent Diabetes (ISPAD), covers advice for children, adolescents and adults before, during and after exercise.

Decisions around carbohydrate intake, insulin correction or exercise timing are based on an assessment of the patient’s habitual physical activity, risk of hypoglycaemia and health status along with the type, intensity and duration of exercise, and data from sensor glucose values and trend arrows.

“In this position statement, we detailed the use of sensor glucose values accompanied by trend arrows for CGM and isCGM systems for different groups of people with type 1 diabetes and for different sensor glucose responses to exercise,” the statement said.

“Of note, in this position statement, recommendations for carbohydrate consumption were stratified with respect to the rate of change in glucose for the pre-exercise phase, during exercise, post- exercise and the nocturnal post-exercise phase.”

The recommendations represent initial guidance only and should be tailored for individual patients, the authors said.

Co-author Dr Carmel Smart, from the Department of Paediatric Diabetes and Endocrinology at John Hunter Children’s Hospital in Newcastle, told the limbic that the statement was complicated – which put the onus on health professionals to translate for their patients.

“From a practical point of view, there are a lot of people who have totally unplanned exercise and I think part of the problem with this paper is it is a mismatch between elite [exercise] people versus everyday people.”

For example, the recommendations for sensor glucose targets during exercise were probably not as relevant for most people compared to the recommendations for before and after exercise.

“Of those three timings, certainly if you are doing exercise for an hour and you are a kid who is relatively stable, then we would probably say pay attention to the ‘before exercise’. Are you trending down? If the glucose is 5 mmol/L and you are trending down, then you definitely need to have 15 grams of carbs.”

“But if the arrow is going straight down, we might say you need to be up around the 20 gram mark [for carbohydrate ingestion] … if the arrow is flat, all good, just have your 10 grams.”

“And then at the end of exercise, most people don’t look at it straight afterwards because it still tends to trend down. When they might look at it is going to bed. And if it is still trending down, we need to make sure we drop the [insulin] dose or have some additional carbohydrate then.”

Dr Smart said clinical practice in Europe, where the position statement was written, was much more arrows based than in Australia.

“The feeling in our clinic is we achieve really good outcomes yet we don’t use arrows all the time.”

However she said the overall experience at John Hunter Children’s Hospital during COVID, was that more children were using CGM.

“We’re asking them a lot more because when you do telehealth, you need data and that is the best way to get data.”

She said the key message to patients with type 1 diabetes who were active was that CGM data can help them improve their glycaemia around exercise.

“Put it on. Keep it on. It’s fantastic to enable you to get the trends about what happens with blood glucose levels around exercise. If you are doing very high intensity exercise like sprinting or competition, you usually go high then go low later. Expect that. That’s normal. And CGM will show you that.”

The position statement has been endorsed by JDRF and supported by the American Diabetes Association.

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