We breathe in accordance with our ever-changing metabolic needs. Our need for breath, for oxygen, changes in response to our activity level, our emotions, our posture, our environment, and other factors. And the breath adapts itself instantly and with uncanny accuracy to these changes—even in the course of a single breath.
For example, begin inhaling and in the middle of the inhalation, hold one nostril shut. You reflexively do one of two things—but not both—to make up for the resulting deficit of breath: either prolong the phase of inspiration, or inhale with greater force. Or, try this: intentionally prolong your expiration. This induces mild, momentary hypoxia (oxygen deprivation). As a result the subsequent inspiration is spontaneously deeper than the one before it.
Reflexes like these ensure that we receive exactly the right amount of oxygen for each moment of our lives. But ask yourself, exactly how much oxygen do we need for any given moment? The answer is not available to introspection; the wisdom of the breath is of the body, not the mind. All of that, and more, makes the breath one of life's great mysteries.
One of several mechanisms that the body uses to adjust oxygen consumption is the expiratory pause. This is a period at end of exhalation during which respiratory movement spontaneously ceases for a time. This expiratory pause is neither "holding the breath," nor "waiting." (A hat tip to my colleagues on the FeldyForum discussion group for their insightful speculations in this regard.) Rather, it is an effortless, involuntary, reflexive mechanism necessary for health, vitality, and life itself.
Some expiratory pauses are longer, others are shorter. When there is a surplus of oxygen in the body, as often occurs during periods of physical stillness or deep relaxation, the expiratory pause may become longer to allow surplus oxygen to be expended. A very long expiratory pause can last as long as one complete breath cycle, or even longer, as if we had skipped a breath entirely. When our oxygen requirement is greater, for example during vigorous activity, the expiratory pause may become very short, even imperceptible, to allow the instantaneous inflow of fresh oxygen.
In Zen and the Brain, James H. Austin, M.D., writes eloquently of the expiratory pause. "Which of our basic human emotions shows an increase during this pause?" he asks. "Only tenderness. In contrast, fear lengthens the phase of inspiration and increases the amplitude of breathing."
The breath is an exquisitely delicate mechanism, vulnerable to all sorts of insults and disturbances from the stress of life. Let us relinquish manipulation and control of the breath, instead honoring it as something truly, deeply unknowable, yet wondrous and all to the good.
May we treat the breath with that same tenderness with which the breath treats us.