3. Factors Affecting Blood Glucose Concentration and Challenges to AP Systems

An AP system is challenged by several factors such as meals, exercise, sleep and stress that may have significant effects on glucose dynamics in the body. In this chapter, the relationship between these factors and the glucose dynamics are discussed. Most AP systems are based only on glucose measurements. These systems usually require manual inputs or adjustments by the users about the occurrences of some of these factors such as meals and exercise. Alternatively, multivariable AP systems have been proposed that use biometric variables in addition to glucose measurements to indicate the presence of these factors without a need for manual user input. The effects of different types of insulin as well as use of glucagon in AP systems is also discussed. The chapter includes a discussion of time delays in glucose sensors that affect the performance of predictive hypoglycemia alarm systems and APs.