Infusion systems, infusion devices, and related operating methods are provided. An exemplary method of operating an infusion device capable of delivering fluid to a user involves a control system associated with the infusion device obtaining a first measurement indicative of a physiological condition of the user from a first sensing arrangement, obtaining one or more measurements from a second sensing arrangement indicative of a second condition of the user. The control system classifies the second condition as corresponding to one of a plurality of intensity levels based at least in part on the one or more measurements, and thereafter operates the infusion device to deliver the fluid to the user based on the first measurement of the physiological condition in a manner that is influenced by the intensity level classification.