Ok this is weird but honestly the sound of a heart beating helps me sleep because it's soo calming. It helps me sleep better and like when hear someone's heart beating it makes me feel all weak and just sleepy but in a safe feeling way. Like im secured forever in their arms. So yea heartbeats help me sleep :) I like to lay on a man's chest and just hear the beating in my ear and I fall asleep and it's like their heart is gonna pop out of their chest or something cuz it's at a steady beat. And it's music to my ears.