P-170: Retrospective investigation of biometric sensors during exercise in hikers with T1D (RISE-T1D)
L Norlander, K Kingston, R Kingman, D Zaharieva, A Kanow, R LalAbstract
Introduction
Physical activity is central to type 1 diabetes (T1D) management; however, glycemic responses to prolonged, multi-day exercise are not well described.
Objectives
To characterize glucose dynamics, insulin delivery, and activity patterns in youth with T1D during a high-altitude backpacking trek.
Methods
This retrospective observational study analyzed device- and log-based data from nine participants (ages 15–24) during a 10-day trek comparing it to data from the preceding four months. All used continuous glucose monitoring (CGM) and automated insulin delivery systems. Data were obtained from CGMs, insulin pumps, smartphones, and activity trackers; three participants also wore continuous ketone monitors (CKM). Altitude ranged from 2,926 to 4,421 meters and movement time was 2.5–13 hours/day.
Results
During the trek, time in range (70–180 mg/dL) increased to 76.3% compared with 69.9% pre-trip. Time below range remained low (<70 mg/dL: 1.0% vs 0.9%; <54 mg/dL: 0.2% vs 0.1%). Time above range decreased (>180 mg/dL: 18.7% vs 22.0%; >250 mg/dL: 3.9% vs 7.3%), and mean glucose declined (150 vs 159 mg/dL). Daily carbohydrate intake rose (192 vs 148g), as gathered from pump data, while total daily insulin fell to 61.5% of pre-trip levels. Additionally, participants consumed an average of 54 g/day of uncovered carbs, based on daily recall. Activity increased markedly, with steps rising from 8,198 to 22,660/day (+289%). CKM values ranged from 0 to 2.6 mmol/L; all ketone elevations were asymptomatic, and the mean glucose with ketones >1.0 mmol/L was 165 mg/dL.
Conclusions
High time in range can be maintained during prolonged exercise at altitude in T1D but requires substantial insulin reduction and increased carbohydrate intake. Elevated ketones were asymptomatic and more correlated with exertion than hyperglycemia. These findings highlight the importance of proactive planning for safe participation in multi-day endurance activities.