A system for measuring a patient's inspiration volume and for enhancing patient compliance with a predetermined breathing pattern during inspiration volume measurements. A flexible conductive loop adapted for being wrapped around, and conforming to the patient's chest is coupled to an amplifier circuit including a signal generator and an exclusive-OR gate. The signal generator generates a square-wave signal for coupling to a first terminal of the conductive loop and the exclusive-OR gate is responsive to the applied square-wave signal and to a signal at the second terminal of the loop for measuring the delay between the signals. The output signal of the amplifier circuit is indicative of the inductance of the loop, which varies with the patient's inspiration volume. The measured inspiration volume is displayed on a first display and a target inspiration volume is displayed on a second display, preferably, disposed adjacent to the first display. The patient is instructed to breathe in a manner that causes the measured inspiration volume display to match the target inspiration volume display. In one embodiment, a measure of the patient's compliance with the predetermined breathing pattern is provided.