I was laying in bed the other day, with a throbbing headache. As I tried to nap against four pillows and bundle myself in the sheets and blankets, I could hear my heartbeat echoing in my ear, and could feel the blood rhythmically pounding in my temples.
As I tried to force myself to sleep, I started taking long deep breaths. I discovered that as I started to inhale, my heartbeat slowed down and the pounding in my temples went from very rapid to calm and slow. As soon as I began to exhale, however, the calm and slow quickly reverted to rapid pounding. I tried this several more times and realized that it was happening consistently. Inhale slow heartbeat; exhale rapid heartbeat.
Why was my heartbeat slowing down when I inhaled?
Before starting my research, I came up with a hypothesis of my own. I made the assumption that on inhale the body wants the blood to gather as much oxygen from the lungs as possible, so it slows the blood down to give it more time to gather. When exhaling the body wants to get rid of carbon dioxide as quickly as possible, so it rushes the blood through the lungs to get rid of the CO2. Anyway…that was my thought, not being a medical student myself, and really having insufficient knowledge about the process to know better.
Then I started the research…and discovered that I should apparently be experiencing exactly the opposite of what I did…namely, that my heartbeat should be increasing when I inhale and decreasing when I exhale.
It’s called sinus arrhythmia, from what I’ve found online (I did not feel it necessary to pay a co-pay at my doctor’s office in order to write this post), and it’s described as:
Sinus arrhythmia: The normal increase in heart rate that occurs during inspiration (when you breathe in). This is a natural response and is more accentuated in children than adults. [Reference: medicinenet.com]
Odd – exactly the opposite behaviour that my heart should have been exhibiting. However, on that same page I found this reference:
Sinus tachycardia refers to a fast heartbeat (tachycardia) because of rapid firing of the sinoatrial (sinus) node. This occurs in response to exercise, exertion, excitement, pain, fever, excessive thyroid hormone, low blood oxygen (hypoxia), stimulant drugs (such as caffeine), etc.
Perhaps this is what I was experiencing. I was indeed under the influence of caffeine, and was experiencing pain in the form of a migraine. Although, I’m not sure why this would explain why my heartbeat slowed down when inhaling, then resumed it’s “tachycardia” when exhaling.
Has anyone else ever done this little experiment of measuring your heartbeat during deep inhales and exhales? Are you arrhythmical or tachycardial? (I realize those are probably not actual words, but spell check didn’t seem to mind)
