A wrist-worn device comprising a display for showing a heart rate parameter value, such as a heart rate measured from a person's body or a heart rate variable derived from the heart rate. The display comprises at least two display areas which display areas the wrist-worn device is arranged to employ to show that a heart rate parameter momentarily belongs to a heart rate parameter value range corresponding to the display area and which wrist-worn device comprises at least one sliding means for selecting a desired heart rate parameter value range by mechanically sliding the sliding means to cover at least one display area at a time.
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