What counts as a heart beat? usually throughout the day i just hear lup, lup lup. but at night i hear lup dup, lup dup, why is that?

A bit more complex: Remember that your heartbeat is best monitored at your heart. What you hear may be distorted by external factors. Without a stethoscope, it would be hard for you to monitor your actual heartbeat, but if you put your index finger lightly on the inside of your wrist at the base of your thumb, you can feel your radial pulse. Move around till you get it. Each pulsation is your heartbeat.