A method for operating an implantable therapy system to conserve energy includes providing an implantable sensing device that generates a signal as a function of a physiological parameter of a patient during a treatment period. The signal is monitored during at least portions of the treatment period to detect a physiological event for use in controlling therapy of the patient during the treatment period. Energy consumption by the sensing device is terminated during the treatment period for at least portions of the treatment period when signal monitoring is not performed. Another method for operating an implantable therapy system for conserving energy includes providing an implantable component for performance of a function during a treatment period for the therapy system. The implantable component is operable in at least a first state during the treatment period and a second state outside of the treatment period; the first state using more energy than the second state. The implantable component is operated in the first state when performance of the function during a treatment period is required and operated in the second state when performance of the function is not required outside the treatment period. Another method of operating an implantable therapy system includes monitoring a periodic physiological parameter for controlling therapy of a patient during a treatment period. The measured physiological period for the parameter of the patient is compared to at least one predetermined period threshold to determine nonperiodic behavior of the monitored periodic physiological parameter and suspending therapy of the patient as a function thereof. Systems for use with such methods are also provided.