Quieting The Body: The Bedrock Of Meditation

Most people would agree that meditation is calming. How does that work? The basic state of the body—whether you feel excited or calm—is regulated by what is called the autonomic nervous system. This system controls the visceral functions of the body—for instance, it regulates how fast your heart beats, the depth and frequency of your breathing, how strongly your pupils react to changes in lighting, how your sexual arousal fluctuates, the progress of your digestion, when you blink your eyes, when you swallow the food you are chewing, or how much to salivate or sweat.

The system is called autonomic because it typically operates in an involuntary way, that is, outside your awareness or your conscious control. (This is a good thing—imagine you’d have to actually remember to blink your eyes, to swallow your saliva when you chew gum, or to consciously initiate each breath.) That doesn’t mean that certain aspects of the system cannot be
hijacked by conscious control—you can certainly slow down your breathing or hold your breath for a while, or you can take a swallow on command, but most of the time your breathing just happens and you do just the right amount of swallowing for what you’re chewing. Other parts of this system are not under your control: Your stomach and guts just churn away, you can’t directly control your heart rate, and you can’t stop yourself from sweating when you’re hot or nervous.

The autonomic nervous system comes in two flavors—the sympathetic system and the parasympathetic system.
The sympathetic system deals with emergencies. It preps you for fight or flight by readying the bodily systems that might need to spring into action.

Do not panic, keep it calm always

Thus, when something bad happens to you, the sympathetic system increases your heart rate and your breathing rate and it opens up the bronchioles in the lungs so that your muscles and brain can receive more oxygen; it will also release glucose—extra fuel—into the blood stream. At the same time, it shuts down the bodily systems that aren’t necessary for the fight-or-flight response—they would just sap much-needed energy away from the action.
For instance, in times of excitement, blood flow to the stomach and gut is largely cut off, so digestion stops. You’ll also try to dump all the extra weight you can—you might need to make a run for the bathroom.
The parasympathetic system, in contrast, maintains our natural state of relaxation. It calms the body down and keeps its basic functions going. The parasympathetic response has been labeled as “rest and digest” or “feed and breed”: Heart rate and breathing rate slow down, digestion proceeds apace, and, if you feel amorous, go for it.

These two systems work in opposition: When one is active, the other is suppressed. You cannot be angry and cool and collected at the same time; it’s hard to be at peace with yourself while you’re at war with the world. It will come as no surprise that meditation is primarily an exercise in parasympathetic activation. The first thing you do when you meditate is settle down, often literally in a space of calm—low light, shielded from noise, pleasant smells. You shut out most of the external world and turn to a calming stimulus, often the breath. This settling down can be nicely seen in a set of parasympathetic effects.

 You will get pass the ups and down

First, heart and breathing rate slow down. In the four studies I was able to find that provide actual numbers, heart rate went down from, on average,
70.5 beats per minute before meditation—when the meditators were simply sitting relaxed and quietly on the cushion—to, on average, 64.7 beats per minute during actual meditation. Likewise, breathing frequency decreased from 14.3 breath cycles (one in-breath, one out-breath) per minute to 10.7 cycles per minute. Put differently, during quiet rest, one breath cycle takes you, on average, 4.2 seconds; during meditation, one breath takes about 5.6 seconds. There is also a tendency to shift from chest breathing to more diaphragmic breathing (i.e., belly breathing, or deep breathing). The combined effect of these changes is a decrease in oxygen uptake, as well as a decrease in carbon dioxide elimination. This is not a reason to worry—this effect is really small, comparable to what happens during sleep or simple rest.

In the one study that reported this, there was a strong negative correlation (r = –.57) between the number of years of meditation practice and how much breathing rate slowed down—people who have been meditating longer settle more easily into this state of meditative calm. Second, heart rate and breathing rate are synchronized. For instance, Cysarz and Büssing asked five inexperienced meditators to simply rest, perform mental calculations, or do sitting or walking meditation. There was little coordination between heart rhythm and breathing frequency during rest or math but almost perfect synchronization during either form of meditation (not one on one, of course: There are typically multiple heartbeats per breath).

The sense of calmness

This is likely a natural byproduct of low breathing frequency slow breathing makes it easier for the heart to get in synch with the breathing pattern.
Interestingly, one study found that the heart–breath coupling is strongest at a breathing rate of 10 breaths per minute, which, as we just saw, is the average breathing frequency in meditation. This synchronization is stronger in more experienced meditators and also more regular: For experienced meditators,
a ratio of four or five heartbeats per breath was most common (incidentally, this is also the synchronization pattern that occurs during deep sleep); inexperienced meditators do not show a preference for any specific ratio.

The end result of heart–breath synchronization is a pervading sense of calm.
There are other parasympathetic effects as well, such as an increase in galvanic skin resistance, which is a technical term indicating that during meditation you produce less sweat. There is also an increase in slow brain waves (i.e., alpha waves), also typical of your brain going into relaxation mode. When this state of calm and relaxation endures for a while during a retreat, for instance—there can be a decreased need for sleep and food. One study noted a 25% average decrease in sleep duration in participants in a threemonth retreat; the kitchen reported a decrease of one-third in food consumption.11 These changes were particularly conspicuous in those retreatants who reported periods of very strong concentration and mindfulness. One reason may be that long-term meditation, as a relaxed, parasympathetic state, takes over some of the role of non-REM sleep—I’ll say a little more about that in other post. Another reason is that long-term, frequent meditation is likely to lower your metabolic rate, thus reducing your body’s nutritional needs.