For these many months, I may have been operating under a misunderstanding of basic concepts!
Some questions:
(1) Am I correct that RSA (Respiratory Sinus Arrhythmia) and HRV (Heart Rate Variability) are more or less interchangeable concepts?
(2) Where I may have been going wrong is misunderstanding the nature of "smoothness" ("coherence" in HeartMath jargon). I have been treating "smoothness" and HRV as if they are more or less interchangeable. However, it has come to my attention that they are measuring different things. Is that correct? If so,
a) I understand the concept of HRV, but I guess I don't understand "smoothness." What is smoothness
measuring? What is it's relationship, if any, to HRV? What is the significance of "smoothness"? Why is it
useful as distinguished from HRV?
b) HeartMath says that "coherence" is most strongly produced by adopting feelings of gratitude, appreciation
and heart-felt emotions. However, my personal experience with adopting appreciation does not produce
much smoothness or HRV, and that breath-lengthening seems the more direct driver.
c) Does this "heart-felt emotions stuff have clinical validity, or is it just "New Agey" stuff masquerading in
scientific jargon?
I welcome any disucssino of this interesting and important topic.
As we exhale our heart rate lowers, as we inhale it rises. This is due to the activation of the vagus nerve. This vagal nerve activity is a sort of relaxation response. So as we exhale we get at least some aspects of relaxation physiologically. Respiratory Sinus Arrhythmia is exactly this, the correlation of the breathing and heart rate.
The words heart rate variability are unfortunately very general. Basically this refers to any variability in heart rate, which can include changes for many different reasons, both sort term and over longer term cycles that can last for hours. People use the words heart rate variability, when referring to heart rate feedback on a computer, in a specific way that doesn't really include all of the variations. People often say they are "training heart rate variability" when they work to basically to synchronize the heart rate changes with the breathing, or create a sine like pattern in the heart rate, that is within a somewhat slow but reasonable breathing speed, even if the person is not breathing at the exact same speed.
The way HeartMath measures coherence is through frequency analysis of the heart rate. This is hard to explain without pictures, but basically when the heart rate shows a nice smooth sine wave, this is a single frequency, whereas a chaotic wave is many frequencies combined together.
Although Somatic Vision's smoothness is also derived from frequency, we try to make it visually simpler for people by calling it smoothness. When you are breathing in a slow and steady manner your heart rate is naturally driven up as you breathe in and down as you breathe out. Stressful or negative thoughts can further impact the heart rate, generally by causing it to rise, which would create spikes within an otherwise smooth pattern (assuming your breathing is steady). When the heart rate looks smooth, you are both breathing in a relaxing way and are not overly stressed (there are numerous studies showing the positive effects of breathing on relaxation, and even common folk wisdom when you are angry, stop and take a deep breath). We call this smoothness, as you can see the line showing your heart rate is smooth. We don't call this HRV, even though others do, as it is both ambiguous (which heart rate variations?) as well as complicated for the average user.
If you are in a stressful state, whether that be mental stress, or physical stress, simply controlling your breathing will not be sufficient to achieve high smoothness / coherence. A positive emotional state is required for smoothness / coherence (physical health can also be important, disclaimer: we are not offering medical advice, for medical advice see a doctor). If you are feeling depressed, angry, scared, or are very hungry, thirsty, have to go to the bathroom, have recently had caffeine, etc., you will have a hard time smoothing your heart rate changes. Your heat rate changes are strongly affected by your nervous system changes, which are strongly affected by your emotional state, so yes, feelings of appreciation will definitely impact your heart rate, and overall will help you achieve smoothness. If, on the other hand, your emotional state is basically ok, then breathing speed will be a primary factor. Regardless, training of breathing is immensely important, and the heart rate training reflects both breathing as well as emotional state. I really like this sort of training personally, and find it to be very useful and an excellent indicator of my own stress. Finally, yes, there are many studies showing the correlation between various types of heart rate variability and stress (try a google search "hrv and stress").
Best,
Ryan
Disclaimer for this post: I am not a doctor and neither I, nor Somatic Vision, is offering any sort of medical advice.
