An implantable lead has an inner core, a plurality of coiled conductor guides, and a plurality of conductors. The inner core defines a plurality of lumens. Each coiled conductor guide defines a plurality of helical lumens. Each coiled conductor guide is disposed in a coiled arrangement over a portion of the inner core. Each of the conductors electrically couples at least one electrode to at least one terminal. At least one of the conductors includes a plurality of units. Each unit includes a first conductor segment extending along the inner core from a beginning point to a first position, a coiled conductor segment disposed at least partially in one of the lumens of the coiled conductor guides and extending from the first position to the second position, and a second conductor segment extending along the inner core from the second position to an endpoint.