Ten runners with type 1 diabetes finished a marathon in a similar time to peers without diabetes

What the research found

Study (observational, small). Michał Kulecki, Andrzej Gawrecki, and colleagues at Poznan University report a field study of the 2025 Poznań Marathon, released ahead of the EASD meeting in Milan (EurekAlert 18 September 2026). Twenty amateur runners took part: 10 with type 1 diabetes for at least a year and 10 without diabetes. Mean ages were 35.4 and 39.7 years. Each group had 8 men and 2 women. In the diabetes group, median duration was 16.5 years and HbA1c was 6.4%. Finish times did not differ meaningfully: 228 minutes with diabetes and 248 minutes in the comparison group. Runners with diabetes took in a median 53.5 g of carbohydrate per hour. Finger-stick glucose medians were 183.5 mg/dL at the start, 119.5 at 10 km, 142.5 at 19 km, 121.5 at 30 km, and 108.5 at the finish. Two low readings occurred in one runner, who still finished; that runner had started below 140 mg/dL. Sensors were less accurate on the course. They differed from the finger-stick by about 43% (scanned) and 37% (real-time) and read higher by 32.2 and 50.4 mg/dL. The authors say a finger-stick is worth using when a sensor does not match how a runner feels, and that any insulin plan belongs with a clinician before a race. One small race is not a training plan. Educational notes.

Evidence level: Human study. A study in people, but an association isn't proof of cause.

Read the original at Poznan University of Medical Sciences / EurekAlert