How does the brain get the heart to constantly beat?
Interestingly, in the course of the day, your heart will beat somewhere around 100,000 times and over a calendar year might beat up to 35 million times. Over the course of a lifetime then, your brain and your heart have to work together to engineer 3 billion heartbeats.
The brain gets to take a little break here because the heart will actually beat all by itself. There’s something in the heart called automaticity.
Meaning that the heart, even if it’s disconnected from the brain, will continue to beat at a set rate. It’s called the intrinsic heart rate. And for different people that intrinsic heart rate can be slightly different, but usually sits somewhere around 90-110 beats per minute.
If you have a heart transplant and the heart is then transplanted into another human, it’s not connected to the brain, but that heart continues to beat at a set intrinsic rate.
In addition to the intrinsic heartbeat that the heart has all by itself, the autonomic nervous system is a separate part of the brain and the brain function that can either speed up or slow down your heart.
With that regulation, the rate then has a great deal of variability all throughout the day, depending on what your body needs.