Acute Effects of Real-World Physical Activity on Glycemia in Adolescents With Type 1 Diabetes

Physical activity is not only a key component of overall health and well-being for all adults with diabetes, but is also important in youth and adolescents with type 1 diabetes. However, being active brings with it a whole host of diabetes regimen considerations, such as possible insulin adjustments, food intake, exercise timing, and more. A novel aspect of the T1DEXIP study is its collection of 3319 usable real-world physical activities undertaken by a cohort of 251 adolescents (aged 12–17 years) with type 1 diabetes and the analysis of the various impact of glycemic factors at individual- and event-levels. The authors of the study identified seven individual-level and four event-level factors that impacted glucose change during exercise, the most impactful of which were pre-exercise (baseline) glucose, glucose rate of change before the start of exercise, and estimated insulin on board, which together explained 31.4% of the variance in change in glucose during exercise. Given how many factors are potentially impactful around activities, this low result is not that surprising. The authors concluded that their findings collectively suggest an enhanced exercise sensitivity (ie, a greater glucose drop with activity) in physically active youth who are meeting and/or achieving current consensus guideline goals for glycemic management (HbA1c, <7.0%).

This trial is unique and directly relevant to youth with type 1 diabetes who strive to optimize their glycemic management and health while remaining physically active. Most exercise research for type 1 diabetes has been conducted in a research laboratory setting, which limits the findings of each study to a specific type and duration of activity done at a certain time of day under controlled conditions. Moreover, the results have been variable when it comes to acute and chronic glycemic control. The limited applicability afforded by most prior studies has been suboptimal for creating guidance for exercise-related blood glucose management given that, in reality, adolescents undertake a wide variety of sports and daily planned and spontaneous activities.

Moreover, many adolescents use both CGM and insulin pump therapy technologies, and this cohort was no exception; 98% of adolescent participants were current CGM users, 30% used a standard insulin pump therapy, 55% used a hybrid closed-loop system, and only 15% used multiple daily insulin injections. Studies such as this one will assist in better quantifying the primary influences on glycemic balance around a much wider range of physical activities. Given how challenging it currently is to fine-tune exercise management strategies and develop effective hybrid closed-loop algorithms specifically for exercise, this extensive real-world dataset will surely help many active adolescents with type 1 diabetes.