Closed-Loop Insulin Therapy Exercise Adaptation
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Solution Overview
Problem
Closed-loop insulin delivery systems face challenges in accurately managing blood glucose levels during exercise, as they tend to increase insulin delivery in response to rising glucose levels, leading to potentially dangerous drops in glucose levels during physical activity.
Innovation Solution
The system reduces the target insulin on board (IOB) during exercise, responding less aggressively to pre-exercise food intake and avoiding the buildup of insulin that could cause low glucose levels, by modifying the IOB algorithm to account for exercise intensity through adjustments such as reducing the IOB target, lengthening insulin duration time, and introducing a temporary basal rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the closed-loop system increases insulin delivery in response to rising glucose levels after exercise, then glucose control is improved, but severe hypoglycemia occurs due to excessive insulin combined with exercise-induced glucose lowering
Solution Approach 1:
The system applies preliminary anti-action by detecting exercise parameters (heart rate, activity level) before glucose levels drop, and preemptively adjusting insulin delivery downward to counteract the combined effect of exercise-induced glucose lowering and insulin action. This prevents hypoglycemia before it occurs rather than reacting after glucose levels fall.
Solution Approach 2:
The system implements dynamics by continuously adjusting insulin delivery based on real-time exercise intensity measurements. As exercise intensity changes, the insulin delivery rate dynamically adapts, allowing higher delivery during low-intensity phases and reduced delivery during high-intensity phases when glucose consumption increases.
2Measurement precision
If the system responds aggressively to pre-exercise food intake by increasing insulin delivery, then post-meal glucose control is improved, but insulin buildup occurs that causes dangerous glucose drops during subsequent exercise
Solution Approach 1:
The system performs preliminary action by detecting the start of exercise and immediately modifying insulin delivery parameters before glucose levels have time to drop. This preemptive adjustment prevents the insulin-glucose mismatch that would otherwise occur with standard aggressive insulin delivery protocols.
Solution Approach 2:
The system applies parameter changes by modifying insulin delivery parameters (rate, duration, timing) based on detected exercise intensity. The control algorithm adjusts key parameters such as insulin sensitivity factors and target glucose levels to account for exercise-induced physiological changes.
3Measurement precision
If the closed-loop algorithm increases insulin delivery upon detecting rising glucose levels, then glucose normalization is achieved, but the combination with aerobics exercise causes severe glucose drop
Solution Approach 1:
The system implements feedback by continuously monitoring multiple parameters (glucose levels, heart rate, activity intensity) and using this feedback to dynamically adjust insulin delivery. The feedback loop detects exercise onset through physiological parameter changes and responds by modulating insulin delivery to prevent hypoglycemia.
Data Source
Figure 1
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Figure 3A~3B
AI summary
Disclosed herein are apparatuses and methods that account for exercise in closed loop insulin delivery systems. Rather than increasing a target insulin on board (IOB) as glucose levels rise, which would increase insulin delivery to address the raised glucose levels, when a user indicates that the user will be exercising raised glucose levels are addressed by reducing the target IOB within the closed loop algorithm. By reducing the target IOB, the algorithm responds less aggressively to pre-exercise food, and does not build up the IOB that can cause dangerously low glucose levels once the exercise also begins lowering glucose levels.