Type 1 diabetes and extreme endurance sports: 25 marathons in 1 month.

Type 1 diabetes (T1D) is an autoimmune condition in which the pancreas stops producing the hormone insulin. Insulin has many functions, among them, regulating blood glucose levels and thus also the adequate utilization of liver glycogen and fatty acids. T1D usually occurs in children or young people and its main treatment is the application of insulin.

Because insulin also plays an important role in regulating the body energy when exercising, performing any type of physical activity can be challenging for a person living with this condition, if not instructed in how to modify their treatment and / or diet around physical exercise. For health professionals it is also an issue in which there are many gaps and lack of instruction so there are many cases of young people who want to perform sports disciplines and are not allowed by their doctors or health team. This should not be the case, since with an adequate education on this subject both from the health professional or even the physical trainer as well as from the person who lives with the condition, achieving any sporting goal is possible.

This was the case of the marathon runner Gavin Griffiths of London England. He is 27 years old and lives with T1D since he had 8 years of age. Gavin not only decided to run a marathon but 25 in just 1 month for reasons of fundraising and raise awareness about his condition throughout the United Kingdom and Ireland; facing different terrains, climates and foods. The biggest "danger" to perform a challenge of this type when living with T1D is hypoglycemia (low blood glucose levels) which can be dangerous if it is very severe and also affect performance during marathons. However, with an adequate nutritional, medical and technology approach, the risk of hypoglycemia can be minimized.

Gavin was accompanied by myself and instructed on adjustments in nutrition and treatment during the entire marathon period. He used a continuous glucose monitoring, which notified on his and my cell phone how his blood glucose levels were in real time and what its tendency was. Through this device we could prevent their levels from going too low or too high while running, this through adjusting with simple carbohydrates (gels, gummies, glucose tablets) and complex carbohydrates (bars, fruits, compotes, sandwich) according to their level and tendency. The insulin adjustments were made daily, needing less insulin than usual at the start of the marathons. While advancing in the month, the body was adapting to this daily marathon routine and required fewer adjustments of its dosage, almost reaching what would have been required in his day to day out of the marathon period. In addition to the blood glucose levels, weight, heart rate, marathon duration, race pace and distance traveled were also measured daily. Regarding blood glucose levels, 60% were in an adequate range during the month and there was no severe hypoglycemia. During the marathons he only had 4 mild hypoglycemia, which occurred on days with higher temperatures. We noticed that temperature, the terrain where he was running, the state of mind, the precision in the carbohydrate count before and during the marathons, the sleep and the insulin adjustments were the factors that most determined the blood sugar levels. Regarding his weight, there was no significant loss, only -1kg, which was recovered after 1 week of finishing the marathons. There were also no injuries, cramps or drastic changes in performance and also the calculation of body water percentage was maintained, so it is considered that there was no dehydration at any time.

How we achieved it?

• Adequate communication between professional and patient is extremely important. The patient has knowledge about his body and if he is an athlete, he also knows how his body reacts to exercise. In this case, Gavin had already made another similar challenge (30 miles in 30 days) without professional help and did not have good physical results. However, this previous experience can join the present professional experience and act in a more precise way for better results.

• Apply principles of sports nutrition and adjust them to the knowledge of sports physiology and T1D. Supplements and hydration protocols were included as well as a person without diabetes. The recommendations of general sports nutrition that varied the most were the grams of carbohydrates per hour. In a person with type 1 diabetes, it is difficult to tolerate high amounts of carbohydrates per hour when exercising because you are not injecting insulin for them. For this reason Gavin consumed 15-40 g of carbohydrates per hour according to the tendency of his blood glucose levels. Consuming more carbohydrates than necessary could increase blood glucose levels (hyperglycaemia). It is not good to exercise with hyperglycaemia because it affects performance and causes dehydration.

• Trial and error: some days we tried treatment and nutrition adjustments that worked and others don’t. We registered all those adjustments so that the next day was a more precise approach. Each marathon was different and the body reacted differently, so it is necessary to have a base plan, act accordingly and adjust as necessary.

No challenge is impossible for both health professionals and athletes living with a chronic condition. The key is in the adequate knowledge about the practiced sports characteristics, knowing about the specific condition and teamwork with the athlete to obtain success as a result.


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