How did blues music influence heavy metal bands such as Led Zeppelin and AC/DC?

Heavy metal is deeply rooted in blues music, which provided the foundational sound for bands like Led Zeppelin and AC/DC. The genre evolved largely by simplifying the loud, distorted riffing characteristic of British blues guitarists.12

Led Zeppelin
Formed from the remnants of the Yardbirds, Led Zeppelin blended blues with other genres to create a powerful, bottom-heavy electric style that served as a precursor to heavy metal. Their influence from the blues was profound:34
* Guitar: Jimmy Page’s solos were primarily based on melodic ideas derived from the blues scale.4
* Vocals: Robert Plant exaggerated the expressive palette of blues singers like Muddy Waters and Howlin’ Wolf, establishing the high-range, distorted, and emotionally charged vocal style that defined hard rock and heavy metal.4

AC/DC
AC/DC’s music is also solidly grounded in the blues tradition. The band’s early records and live performances, which established them as favorites in Australia before their international success, were explicitly blues-based. This foundation remained central to their "tight, clean metal punch" throughout their career.25