What is the highest heart rate possible for the human heart?
In order to trigger a muscle cell to contract, an action potential has to be generated. As the electrical signal reaches each myocyte (the muscle cells in the heart) they are said to depolarise, meaning the cell goes from having a negative electrical balance across it’s membrane, to having a positive electrical balance, resulting in an action potential. The electrical balance is reglated by various channels that allow certain charged atoms (ions) through. There are different types of channels that open and close at different times, but once an action potential has been generated, there is what is called an absolute refractory period, whereby the channels need to be reset before another AP can occur. This lasts about 0.2 seconds, so in theory you could have a heartbeat every 0.2 seconds, meaning a heartbeat of 300 beats per minute (5 per second x 60 seconds). However, following the ARP, there is a relative refractory period – some cells have reset and can produce another action potentia
