This tender, vaudeville-style piano ballad is about singer Alison Mosshart's inability to "survive on a halfhearted love that will never be whole.'" It is possibly the most un-Kills-like track the duo has ever recorded. "It just sounds like it dropped out of the sky, like it's always been around," guitarist Jamie Hince told Billboard magazine: "It sounds like one of those classic songs. That's easily one of my favorites on the record, probably because it is so different."
The song finds Mosshart unleashing her inner cabaret singer. Blood Pressures was written and recording whilst the vocalist moonlighted with the Dead Weather. Hince told Spinner he felt that the vocalist's time with Jack White's outfit had given her, "a voice much stronger and more confidence vocally," that was a bit of a double-edged sword. "For me, I like the vulnerable side of her voice," he said. "I don't just like the loud rock voice. To me, using that is almost like cheating. I like the vulnerability in her voice, when it cracks and wavers on words. If anything, Dead Weather made me want to steer [the Kills' sound] away from rock. I didn't want this to be a straight rock record."
Hince said of the ballad's nostalgic piano sound to Nowness
: "I wanted to make it completely different from anything we'd normally do. I used an octagon keyboard from the '60s which takes flexi-discs with real bands playing and mixes them together."
Said Mosshart regarding the song's meaning to Nowness: "Life goes on. It starts off being the end of the world but then ends up alright."
The song's music video was directed by actress Samantha Morton (Minority Report, In America) and shot in monochrome on silvery 35mm. The Kills performed their first gig on February 14, 2002 in front of 70 people and the photo booth set clip, which features a series of touching camera poses reflecting the pair's longstanding friendship, celebrates ten years of the transatlantic duo. Said Hince of Mosshart to Nowness: "She's my best friend and has been in every aspect of my life."