Help! Last night as i was sleeping with my boyfriend his heart started pounding really hard and loud. Help! Last night as i was sleeping with my boyfriend his heart started pounding really hard and loud. I could actually see his pulse on his neck bobbing up down. It really terrifed me. His heartbeat was vibrating through my body! I hope nothing is wrong with him. Does anyone know what causes this? He also breathes heavily when he s sleeping. lol sorry I didn t check before posting. He was actually sleeping and I was awake. :-)