A wristop heart rate monitor comprising a dial, which comprises a current heart rate indicator, which is responsive to a heart rate signal measured from a user of the wristop heart rate monitor and functionally connected to a heart rate scale, and a reference indicator defining a visually identifiable reference heart rate range. At least one of the indicators is rotatably adjustable relative to the dial, and the heart rate scale and the reference heart rate range are adjustable relative to each other. A method is also described for monitoring the heart rate of a sportsman. The wristop heart rate monitor provides a quickly perceivable and adjustable heart rate monitor structure.