An infusion system comprising: an actuation arrangement operable to deliver insulin to a user; a glucose sensing arrangement to obtain a measured glucose value for the user; one or more additional sensing arrangements (506, 508) to obtain measurement data indicative of exercise by the user; and a control system coupled to the actuation arrangement, the glucose sensing arrangement, and the one or more additional sensing arrangements to: classify the exercise by the user as one of a plurality of levels of exercise intensity including aerobic exercise and anaerobic exercise based on the measurement data; determine a trend associated with a glucose level of the user based on the measured glucose value and one or more preceding measurements indicative of the glucose level; decrease a time constant associated with the derivative term of a proportional-integral-derivative closed-loop control of the actuation arrangement to decrease responsiveness of the PID control when the trend is positive and the exercise is classified as aerobic; maintain the time constant when the trend is negative and the exercise is classified as aerobic; increase the time constant to increase responsiveness of the PID closed-loop control when the exercise is classified as anaerobic; and operate the actuation arrangement to deliver the insulin to the user by determining a command for operating the actuation arrangement based on a difference between the measured glucose value and a target glucose value using the PID closed-loop control. an actuation arrangement operable to deliver insulin to a user; a glucose sensing arrangement to obtain a measured glucose value for the user; one or more additional sensing arrangements (506, 508) to obtain measurement data indicative of exercise by the user; and a control system coupled to the actuation arrangement, the glucose sensing arrangement, and the one or more additional sensing arrangements to: classify the exercise by the user as one of a plurality of levels of exercise intensity including aerobic exercise and anaerobic exercise based on the measurement data; determine a trend associated with a glucose level of the user based on the measured glucose value and one or more preceding measurements indicative of the glucose level; decrease a time constant associated with the derivative term of a proportional-integral-derivative closed-loop control of the actuation arrangement to decrease responsiveness of the PID control when the trend is positive and the exercise is classified as aerobic; maintain the time constant when the trend is negative and the exercise is classified as aerobic; increase the time constant to increase responsiveness of the PID closed-loop control when the exercise is classified as anaerobic; and operate the actuation arrangement to deliver the insulin to the user by determining a command for operating the actuation arrangement based on a difference between the measured glucose value and a target glucose value using the PID closed-loop control. classify the exercise by the user as one of a plurality of levels of exercise intensity including aerobic exercise and anaerobic exercise based on the measurement data; determine a trend associated with a glucose level of the user based on the measured glucose value and one or more preceding measurements indicative of the glucose level; decrease a time constant associated with the derivative term of a proportional-integral-derivative closed-loop control of the actuation arrangement to decrease responsiveness of the PID control when the trend is positive and the exercise is classified as aerobic; maintain the time constant when the trend is negative and the exercise is classified as aerobic; increase the time constant to increase responsiveness of the PID closed-loop control when the exercise is classified as anaerobic; and operate the actuation arrangement to deliver the insulin to the user by determining a command for operating the actuation arrangement based on a difference between the measured glucose value and a target glucose value using the PID closed-loop control.