Are Athletes With T1D Putting Themselves at Risk for Recurrent Hypoglycemia?

CHICAGO – Nearly three-fourths of people with type 1 diabetes (T1D) who engaged in aerobic activity failed to follow guidelines for preventing hypoglycemia, according to a survey-based study.

Guidelines state that if a person with T1D experiences severe hypoglycemia, they should not exercise for 24 hours, but 73% of those surveyed (n=102 adults) reported exercising even if they were experiencing severe hypoglycemia <50mg/dL in the last 24 hours, reported Joseph Henske, MD, of the University of Arkansas for Medical Sciences in Little Rock.

And despite guidance that patients with T1D should check for ketones if there is unexplained hyperglycemia pre-exercise, 74% said they did not do so, even if glucose levels exceeded 250 mg/dl prior to the workout, he stated in a presentation at ENDO 2023, the annual meeting of the Endocrine Society.

Henske and colleagues also found that 11% said they still exercised when ketones were present, while 10% reported experiencing diabetic ketoacidosis after exercise, and 49% said they did not wear guideline-mandated diabetes identification while exercising.

Also, 86% said they experienced the need to stop exercise due to hypoglycemia, while 18% said they had experienced severe hypoglycemic events that required assistance from another party.

Henske reported at a press conference that less than a third of respondents said healthcare providers were their go-to sources for information on hypoglycemia and exercise. Instead, 80% said they got information from personal trial and error. Other sources included social media, Google searches, and YouTube videos.

"Hypoglycemia unawareness and hypoglycemia management remain significant concerns for athletes with type 1 diabetes," he noted. "Implementation science efforts and development of educational tools to increase awareness of current guidelines surrounding type 1 diabetes and exercise may improve outcomes."

In the survey, 19% of respondents reported a diagnosis of hypoglycemia unawareness. Henske and colleagues explained that "[n]ormal awareness requires feeling symptoms of hypoglycemia above 70mg/dL," but only 11% said they felt symptoms appropriately at >70mg/dL.

Maria Stamou, MD, of Mass General Brigham/Harvard Medical School in Boston, told MedPage Today that "addressing how to handle insulin therapy, and how to respond to hyperglycemia and hypoglycemia around exercise, is a very important topic that needs to be addressed during each patient visit with their providers."

"Talking with each patient about how to prevent, recognize, and treat significant fluctuations in their blood sugar levels during their everyday life has been, and should continue to be, a top priority for the medical teams," said Stamou, who was not involved in the study.

Consensus guidelines on exercise management in T1D came out in 2017. In 2020, the European Association for the Study of Diabetes and the International Society for Pediatric and Adolescent Diabetes released a position statement for glucose management for exercise in T1D that was supported by the American Diabetes Association. In a 2022 Diabetologia review, experts noted that "[m]any competing athletes [with T1D] deal with additional factors that can affect performance. Poor recognition of hypoglycaemia, travelling, optimisation of body weight and/or menstrual cycle variations in insulin sensitivity are a few factors that may have an impact on glucose control and performance."

While they may not have been in line with guidelines, respondents were up to speed with T1D technology, Henske said, with 97% saying they wore continuous glucose monitors and 75% reporting they wore insulin pumps. Many also used a hybrid closed loop system, he stated.

"People with type 1 diabetes who want to exercise and enjoy exercise do struggle with hypoglycemia," Henske told MedPage Today. His group also found that more than a quarter of respondents cited "fear of hypoglycemia" as a major barrier to exercising more frequently, and 41% reported difficulty with overnight hypoglycemia post-exercise.

Henske's group posted the 96-question survey in social media groups for athletes with T1D, including runners and ultra-endurance athletes. Respondents' average duration of T1D was 20 years, and the average reported HbA1c was 7.1%. The goal is to keep HbA1c below 7%, he noted. Mean respondent age was 42. The majority were female, white, and living in the U.S. Finally, 68% reported performing aerobic exercise ≥4 days per week, averaging 23 miles per week walking or running.

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