Take a moment to feel your pulse. You can find it at your wrist, or in your neck. For a few moments, close your eyes, breathe deeply, and notice the pattern of your heartbeat.
Did you notice how much it changed from one heartbeat to the next?
Many people assume that the heart beats at a fairly constant rate, whether fast or slow. But the heart is a little more complicated than that. When we're feeling relaxed (i.e., when the parasympathetic nervous system is dominant), there's a lot of variation in the amount of time between heartbeats. This is called heart rate variability, or HRV.
When we're feeling stressed, afraid, or nervous (i.e., when the sympathetic nervous system is dominant), this variation gets ironed out. The heart rate not only speeds up, but also becomes more consistent; the HRV goes down. The amount of time between heartbeats becomes predictable, staying almost exactly the same every time.
I see an analogy here to the way that stress affects our minds. When we're feeling relaxed, we're creative. We're open to change, adapting to the moment. With each heartbeat, the slate is fresh; anything could happen next.
But fear or stress locks us into a certain pattern. We feel that we can't change. We stick with the exact way that we're doing things. Creativity and adaption go out the window.
I love that feeling of variability. And the beautiful thing about the nervous system is that relaxation –and a higher HRV – is usually only a few deep breaths away.