Man Chiara Dalla, Breton Marc D, Cobelli Claudio
Department of Information Engineering, University of Padova, Padova, Italy.
J Diabetes Sci Technol. 2009 Jan;3(1):56-67. doi: 10.1177/193229680900300107.
A simulation model of a glucose-insulin system accounting for physical activity is needed to reliably simulate normal life conditions, thus accelerating the development of an artificial pancreas. In fact, exercise causes a transient increase of insulin action and may lead to hypoglycemia. However, physical activity is difficult to model. In the past, it was described indirectly as a rise in insulin. Recently, a new parsimonious model of exercise effect on glucose homeostasis has been proposed that links the change in insulin action and glucose effectiveness to heart rate (HR). The aim of this study was to plug this exercise model into our recently proposed large-scale simulation model of glucose metabolism in type 1 diabetes to better describe normal life conditions.
The exercise model describes changes in glucose-insulin dynamics in two phases: a rapid on-and-off change in insulin-independent glucose clearance and a rapid-on/slow-off change in insulin sensitivity. Three candidate models of glucose effectiveness and insulin sensitivity as a function of HR have been considered, both during exercise and recovery after exercise. By incorporating these three models into the type 1 diabetes model, we simulated different levels (from mild to moderate) and duration of exercise (15 and 30 minutes), both in steady-state (e.g., during euglycemic-hyperinsulinemic clamp) and in nonsteady state (e.g., after a meal) conditions.
One candidate exercise model was selected as the most reliable.
A type 1 diabetes model also describing physical activity is proposed. The model represents a step forward to accurately describe glucose homeostasis in normal life conditions; however, further studies are needed to validate it against data.
需要一个考虑身体活动的葡萄糖-胰岛素系统模拟模型来可靠地模拟正常生活条件，从而加速人工胰腺的开发。事实上，运动可导致胰岛素作用短暂增强，并可能导致低血糖。然而，身体活动难以建模。过去，它被间接描述为胰岛素升高。最近，有人提出了一种新的、简约的运动对葡萄糖稳态影响的模型，该模型将胰岛素作用和葡萄糖有效性的变化与心率（HR）联系起来。本研究的目的是将这个运动模型插入我们最近提出的1型糖尿病葡萄糖代谢大规模模拟模型中，以更好地描述正常生活条件。
该运动模型描述了葡萄糖-胰岛素动力学在两个阶段的变化：胰岛素非依赖性葡萄糖清除率的快速开关变化和胰岛素敏感性的快速开启/缓慢关闭变化。在运动期间和运动后的恢复过程中，考虑了三种作为心率函数的葡萄糖有效性和胰岛素敏感性候选模型。通过将这三种模型纳入1型糖尿病模型，我们模拟了不同水平（从轻度到中度）和持续时间（15分钟和30分钟）的运动，包括稳态（例如，在正常血糖-高胰岛素钳夹期间）和非稳态（例如，饭后）条件。
选择了一种候选运动模型作为最可靠的模型。
提出了一种也描述身体活动的1型糖尿病模型。该模型朝着准确描述正常生活条件下的葡萄糖稳态迈出了一步；然而，需要进一步的研究根据数据对其进行验证。
