How Does the Heart Know How Fast or Slow To Beat?
Have you ever wondered how your heart knows exactly when to speed up or slow down? Whether you’re out for a run or taking a nap, your heart adjusts its pace every second. This happens through a complex electrical system that works quietly inside you to keep it (and your body) moving.
Understanding how this process works can help you stay in tune with your heart care and overall well-being. This article explains the different ways your body regulates your heart rate to be appropriate for the current situation.
How Your Heart Drives Your Pulse
Your heart’s rhythm begins in a small group of specialized cells in the top right chamber called the sinoatrial (SA) node. Often referred to as your heart’s natural pacemaker, it generates the electrical signal that starts each heartbeat.
Once the signal leaves the top of your heart, it reaches the atrioventricular node. This node is about the size of the tip of a light switch and acts like a gatekeeper. It purposefully delays the signal for a fraction of a second. This pause helps ensure your top chambers are completely empty before the bottom chambers start to squeeze.
After this short delay, the signal moves into the bundle of His and then out to the Purkinje fibers (both named for the people who discovered them). Together, these parts of the heart look like an upside-down tree.
The bundle of His acts like the trunk, while the Purkinje fibers spread out like a canopy into the walls of the bottom chambers. When the signal reaches these fibers, the bottom chambers contract. This creates the powerful beat that sends blood to your lungs and the rest of your body.
Instructions From Your Brain
While your heart has its own internal timer, your brain helps manage the speed. Your autonomic nervous system tells the heart when it’s time to work harder or rest. This system uses two main branches to control your heart rate: the sympathetic nervous system and the parasympathetic nervous system.
The sympathetic nervous system acts like the “gas pedal.” It releases hormones that make your heart beat faster when you’re active, excited or stressed.
On the other hand, the parasympathetic nervous system acts like the brake. It releases signals that slow your heart rate when you’re resting or sleeping. A normal resting heart rate for most people is 60 to 100 beats per minute.
When To See a Provider About Heart Rate Concerns
Many things can temporarily change your heart rate, such as caffeine, exercise or deep breathing. In those cases, the difference in rate isn’t cause for concern, especially if your heart returns to its normal resting rate after the effects wear off.
However, the electrical system sometimes glitches. This can lead to an irregular rhythm known as atrial fibrillation or to other arrhythmias. Some people may also experience an unusually slow rhythm called bradycardia.
You should reach out to a primary care provider or cadiologist if you experience symptoms such as chest pain, fainting or shortness of breath. They can use tools such as an EKG or an echocardiogram to evaluate your heart’s structure and electrical activity and help ensure your system is functioning properly.
Talking with your Baptist Health cardiologist can help determine whether further testing or treatment is needed. If you do not have a Baptist Health cardiologist, you can find one by visiting our provider directory.
