I always wondered what the link was. Between how you breathe and your heart rate. Have you even noticed how your heart rate increases as you pant? Or how you can slow down your heart rate by breathing slowly or deeply. I don’t know about you but I tried to check just how much. On my watch. I could see my heart rate slow down by up to 15 beats per minute. Just by breathing slowly. So what gives? Actually, your heart beat is linked to breathing. It’s called respiratory sinus arrhythmia or RSA. In fact when you breathe in your heart rate increases. It slows down when you exhale.
Your heart rate is controlled by what is known as your automated nervous system. It has two parts. The sympathetic nervous system (SNS) which speeds up your heart rate. It does this by releasing hormones and chemicals. Often this is a response to an emergency. Your parasympathetic nervous system (PNS) located in the stem of your brain slows down your heart rate. Research teams are yet to discover the precise linkage between your heart beating and your breathing. One theory is when you inhale, it exerts pressure on your rib cage. This makes your heart rate slow down.
Another interesting theory is that your heart rate slows down with an increase in carbon dioxide in your body. So if you breathe slowly and deeply, you are taking in more air, but as a result, you are also holding in carbon dioxide longer. This increase in carbon dioxide causes a corresponding relaxation of the heart. This is the reason why you are asked to breathe into a bag if you are hyperventilating. It increases the amount of carbon dioxide.
All my life, I thought we breathe to take in oxygen. It is a revelation that carbon dioxide is equally important.