My Take: Breathing and Anxiety
Does breath control reduce anxiety? If it does, is it activation of the parasympathetic nervous system the mechanism or is this one of the most pervasive fallacies in medicine?
The nose is for breathing, the mouth is for eating. ~Proverb
Breath control helps reduces anxiety/panic - everybody knows that! Many also think they "know" how and why. I don’t.
Focusing on the breath can quell anxiety. I was taught that deep breathing?, slow breathing?, breath holding?, increased parasympathetic (PS) nervous system tone. This reduced or balanced the excess sympathetic tone (e.g. "fight or flight response") characteristic of anxiety, restoring the yin/yang of this pair. After an extensive review of the literature I’m not convinced. I found little, if any, evidence in controlled studies that any breathing pattern directly reduced anxiety in humans. Classically performed by Yogis, breath control (Sanskrit–Pranayama) can induce a state of profound relaxation. A regular, deep breathing pattern driven by the diaphragm during inhalation, pulling air through the nostrils (where it is filtered and humidified) into the lungs, with the abdomen and chest expanding is essentially "normal." The choppy, rapid, shallow breathing pattern of anxious patients is often dominated by chest > abdominal breathing. Hyperventilation can cause numbness and tingling around the mouth and extremities as well as lead to lightheadedness or fainting (producing more anxiety, fueling a vicious cycle). If one is able to control (normalize) breathing during a panic attack, is it any wonder this produces relaxation?
Many studies measuring activity in the vagus nerve (PS tone) during controlled breathing exercises performed by anxious subjects often reveal reduced anxiety without change in vagal tone. Pranayama comes in many flavors, all of which produce relaxation. Variations include inhalation through the mouth, inhalation through alternating nostrils, inhalation through the right nostril with exhalation through the left, exhalation that reproduces the humming sound of the black Indian bee, or breath holding before breathing out or at different times during exhalation, to name a few! Though a fan of Eastern medicine, as a scientist (and natural skeptic) knowledge requires factual belief, or justification. For me to accept an explanation, it has to "make sense." As I understand anatomy, it is not logical that alternate nostril breathing triggers a direct physiologic response!
Why does relaxed, controlled breathing in any form, result in a state of calm? The answer is not known but likely multifactorial;several explanations make sense to me.
Distraction – a"known"anxiolytic – clearly occurs as one shifts focus from a noxious stimulus to anything else. The more specific and complicated the technique is, the more distraction takes place. For instance, I suspect there is nothing magical about the well known "breath" or "4-7-8" breath espoused by Dr. Weil, where the panicked person shifts focus to adjust how long his inhalation, breath hold and exhalation take. I imagine if one becomes facile at inhaling through one nostril and exhaling through the other, he is less likely to dwell on the irrational fear that a perceived skipped heart beat is the beginning of a fatal heart attack.
A more "normal" breathing pattern feels reassuringly "normal" with the added benefit of eliminating the sensations produced by hyperventilation.
After 20-odd years in the ICU, I am always astonished at the tremendous power of the placebo effect. If you truly believe "4-7-8 breathing" will break a panic attack in 5 minutes, it’s got a very good shot.
Being able to "control" something about yourself when you are, by definition, feeling out of control can provide you with a mental "security blanket."
A study in mice, published in March by Mark Krasnow, MD in the Journal of Science, identified a cohort of cells deep in the brainstem, the "respiratory pacemaker" that connect breathing pattern to various states of mind.
Reported in the shared article (see above) - a publication in the Journal of Neuroscience entitled Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function (December, 2016) describes how the olfactory system (controls sense of smell) with millions of sensory nerve receptors in the upper posterior region of the nose ties nasal breathing rhythm to brain signals relating to memory and behavior. For the first time, this study, utilizing electroencephalograms (EEGs) in human subjects with severe seizure disorders, showed that breathing rhythm (when inhalation occurred through the nose affected brain activity in areas responsible for excitement, memory, emotion, etc.
My take: Mindfulness, practiced as meditation, breath control, Tai Chi, etc. can induce calm for a number of reasons. The classic explanation that specific breathing patterns can halt a panic attack in its tracks through its effect on the PS nervous system may be one of the most oft-quoted and well "known" myths in medical science (please comment if you are aware of high quality supportive data). The human brain does respond to breathing pattern, though the importance of specific findings (e.g., #5-6 above) is unclear. If you are one of the 15-20% of people that suffer from severe anxiety/panic attacks and seek a non-pharmaceutical “cure”, consult an expert. Controlled breathing techniques are tried and true. There are an unlimited number of techniques to try. For maximum benefit:
Use sooner rather than later
Focus
Believe
Experiment with techniques of varying complexity
“Normal” respiratory muscle activation using diaphragmatic breathing, allowing the belly to protrude as the chest expands makes sense.
Now there may be another reason to breathe in through the nose.
Buy stock in aromatherapy (joking or …)