Friday Q&A: Hyperventilation and pH

Calla Lilies by Melina Meza

Two readers pointed out some inaccuracies in a post we re-ran in March 9/11 Anxiety and Yoga regarding pH changes that occur with hyperventilation, or, more specifically for this post, CO2 levels in the brain:

"I believe you are mixing up higher acid and higher pH. If CO2 or lactic acid is high, then the pH will be lower. More acidic is lower pH. And relaxation, which lowers the acid content, will raise the pH."

"I am so glad someone else noticed this contradiction with the CO2 levels and pH, as well. Yes, meditation, and especially deep breathing, will reduce excess CO2 in the system, thus making it more alkaline. People experiencing extreme anxiety tend to have more shallow breaths, which increases the CO2 concentration. This, in turn, increases the anxiety. It is a cycle that is remedied quite effectively with the practice of slow and deep breathing practices."

While we have since made appropriate corrections to our post (both the rerun and the original), I thought that today I’d address the issues that our readers raised.

Before I clarify the pH info from our 3/27/2014 post, I wanted to define what hyperventilation is. According the NIH website: 

“Hyperventilation is rapid or deep breathing that can occur with anxiety or panic (I would add Pranayama, also). It is also called overbreathing, and may leave you feeling breathless.” 

The bold is also my addition to remind everyone reading that you can hyperventilate by breathing too rapidly OR too deeply, or with a combination of both. In all scenarios, the person ends up blowing off too much CO2 via the lungs, thus lowering the amount of CO2 in the blood steam.

However, in my post, I was actually not talking about hyperventilation, but was looking at a study that said that when the brain gets more acidic (lower pH) due to higher concentrations of CO2 in the brain and lactic acid builds up, it could trigger panic attacks. The one change in wording I would make is the following sentence: 

“So if an increase in pH in the brain could be a trigger for anxiety and panic attacks…”

To be more accurate to the study mentioned, this should read (and now does): “So if a decrease in pH in the brain…”

But I also want to clarify what happens in the bloodstream during hyperventilation: as CO2 levels decrease, it actually leads to the blood becoming more alkaline or the pH increasing. “Respiratory” alkalosis can develop as a result of a yoga practitioner hyperventilating while doing yoga, for instance. On the chemical level, hyperventilation is accompanied by too great a loss of carbon dioxide, CO2, from the blood stream and consequent decreases in two other substances, carbonic acid and hydrogen ion concentrations (for you closet chemists out there!) 

There are certain situations in which hyperventilation is more likely to arise, such as in anxious situations, at higher altitude, or in some wind instrument players who play long sustained notes and therefore breathe out and in in an unusual pattern (tuba players are a good example). If you are hyperventilating, you may start to experience dizziness, light-headedness, nausea, dry mouth, numbness and tingling in the arms or around the mouth, shortness of breath, confusion and weakness, to name a few symptoms. And if you are yoga teacher and your student complains of any of those symptoms, this may indicate the student is hyperventilating. (These same symptoms may indicate something more serious, but you can address them as I suggest below while getting help if you deem it necessary.)

In my experience, if I identify someone I think might be hyperventilating, I ask them to sit comfortably and focus on slowing the breath if it is rapid, or even allowing the breath to return to a more normal depth if it is really deep and fast. The student’s symptoms often resolve quickly. One possibility of the effect of slowing the breath down is that you don’t blow off CO2 from the lungs so quickly, and you end up retaining more CO2 in the blood stream, gradually lowering the alkaline blood pH closer to normal. So try these techniques if you think you (or your student) may have been hyperventilating.

The physiology and biochemistry of all of this is somewhat complex and beyond the interest of many of our readers, but for those wanting to dive more deeply into it, Shelly Prosko, our physical therapist/yoga teacher contributor, recommends the book Applied Anatomy & Physiology of Yoga by Simon Borg-Olivier and Bianca Machliss. 

—Baxter

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