How to run an ultra marathon with diabetes

Published by Ultra X
on July 30, 2020


Written by Katie Hickling

Katie is an amateur ultra runner (emphasis on the word amateur — her words, not ours!) who, when not running, tries to fit in a career in financial services technology. Other interests are also known to include dogs, cricket, and writing Ultra X articles.

I have been living with type 1 diabetes for 18 years. I was diagnosed at the age of 7 so I can’t really remember life without it. Type 1 diabetes is an autoimmune condition where the body attacks and destroys the cells in the pancreas that produce insulin. In a normal person, the body is able to maintain blood glucose within a safe margin (typically 5–7 g/mmol).

However, without insulin, type 1 diabetics are unable to control their blood glucose levels exposing them to the dangers of high and low blood sugar. The experience of having a high blood sugar can be described as simultaneously having the flu and a bad hangover. With low blood sugar, the analogy I like to compare it with is when your iPhone runs out of battery and starts to switch off power to non-essential apps. The same scenario occurs with the human body. As a result, diabetics have to try as best they can to control blood glucose by balancing carbohydrate intake, activity levels and taking manufactured synthetic insulin either by injection or infused through an insulin pump.

Running with diabetes

I took up ultra-running about 2.5 years ago. I came from a sporting background having represented my university at triathlon and playing competitive tennis since the age of 10. Although I was used to a busy training schedule managing diabetes, something as demanding as ultra running was always going to be a challenge. However, I remember reading about a type 1 diabetic who summited Everest, so I thought well if they can get someone up there in one piece then I might be able to do this. The past couple of years have been a steep learning curve but I have now learnt to control my diabetes well enough so I am able to take part in these events as any “normal” person would be able to. Diabetes shouldn’t be a hindrance but it is safe to say I am always learning something new.


Some of the extra considerations I have to take into account when training and racing are mainly around carrying enough carbohydrates and back-up medical supplies. For a long run, I will take enough food to make sure I can have a carbohydrate-based snack every 15 mins if I need it, as well as a surplus in case of emergencies. I will also carry back-ups of all my medical supplies so in the event that anything fails I am still able to carry on. This sometimes makes it look like you are setting off for a 100 miler when you are only going out for a 2-hour training run, but after several occasions where I have eaten through all my food supplies within the first hour, it is always better to be over-prepared.


Different types of training also vary in the ways they impact blood glucose levels. A hard tempo or hills session can send blood glucose skyrocketing as it causes large amounts of the stress hormone cortisol to be produced. Whereas a long steady state run can cause blood sugars to drop as it raises your metabolic rate, meaning you burn through glucose a lot quicker than normal. When racing I will look at the course map beforehand and try to predict where certain sections (eg a hard downhill or a sustained climb) might have an impact on my sugar levels, so I know when to take extra fuel or increase insulin.


For any diabetics who are considering taking part in ultra marathons, I suggest seeking the advice of a professional and just going for it. It doesn’t take me to say this, but the NHS is amazing and the teams I have worked with have been very supportive in helping me achieve everything I have wanted to. However, one thing I have realised is that often this is as much a learning experience for them as it is for me. Funnily enough, I don’t think ultramarathons and diabetes are a key topic on the medical school curriculum and most doctors I have worked with haven’t had many patients who have done these types of challenges. So, it is important to develop a good partnership where you can work well together and learn from one another.

Final thoughts

On a final note, I would like to think that the experience of living with diabetes also gives some competitive advantages over “normal” ultra-runners. Firstly, it gets you very well-practiced at fuelling correctly when running and makes you more in tune as to when you need to eat during a race — something which is very important when running long distances.

A lot of ultra-running events also operate on the principle of self-sufficiency and being able to successfully manage yourself well. Having to replicate the job of a failed organ every day does a pretty good of preparing you for this! I have quite a big challenge coming up at the start of 2021 and my experiences of managing type 1 diabetes will be very helpful in the psychological preparation for this.

Last but no means least, it may just get you free race entry. The Lakes in the Day 50-mile ultra held in the Lake District offers free race entry to diabetics. The race director is himself a type 1 diabetic, so uses this as a way to encourage diabetics into the sport. A pretty good incentive if ever you needed one!


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Published by Ultra X
on July 30, 2020

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