Influence of breathing therapy on complaints, anxiety and breathing pattern in patients with hyperventilation syndrome and anxiety disorders - Han et al. (1996)

Key Points

  • Breathing training improved anxiety in patients with hyperventilation syndrome

  • Patients who responded best breathed slower and deeper after breathing therapy

  • CO2 levels were not significantly modified after therapy, suggesting that breathing frequency (slow breathing) and control had the greatest influence on anxiety

The Breathing Diabetic Summary

Breathing training is a common recommendation for hyperventilation and anxiety, both in the general public (how many times have you heard “just take a deep breath”) and in the scientific literature.  For example, we saw in a previous study that breathing retraining improved anxiety and panic attacks by slowing down the breath and increasing carbon dioxide (CO2) concentrations.  In the current study, they set out to examine if the benefits associated with breathing retraining result from modifying breathing behavior after the therapy is completed.  That is, does breathing training modify how patients breathe 24/7, and if so, can that explain its positive benefits with respect to hyperventilation and anxiety?

They studied 92 patients with a clinical diagnosis of hyperventilation syndrome (HVS).  As part of the protocol, they first suggested to the patients that HVS and anxiety were the result of bad breathing.  Then, with the aid of a physiotherapist, they taught the patients to breathe slower and deeper by extending their exhales.  On average, the patients attended 17 sessions lasting 45 min each over a 2.5-month period.  They recorded several parameters related to breathing, including inspiration time, expiration time, breathing volume, and end-tidal CO2.

The main result was that breathing therapy decreased complaints of anxiety.  Interestingly, one of the subjective parameters they measured was the feeling of “faster or deeper breathing.”  A majority of patients increased in this category, which would not be expected after being trained to breathe slowly.  However, this result could be due to the fact that the patients became aware of their breathing and therefore noticed themselves breathing faster and deeper more frequently.

The authors then looked at which breathing variables correlated with improvements in anxiety.  They found that patients who breathed slower, with increased tidal volume, after training had the best results.

Interestingly, CO2 did not appear to play a big role.  Looking at their figures, it does appear that CO2 slightly increased, but it was not significant.  This has important implications.  Because the patients suffered from HVS, if their CO2 did not increase significantly, that means that they were likely still hyperventilating.  Although breathing slower, they were compensating by taking bigger breaths.  However, they still showed significant improvements with respect to anxiety.  To me, this suggests that taking control of your breathing is what matters.  When you control your breath, you feel more in control of your emotions.  This would help reduce the feelings of anxiety that typically accompany hyperventilation.  This also might be why the Wim Hof Method seems to promote calmness even though it involves forced hyperventilation. 

Overall, these results suggest that slow, deep breathing improves anxiety in patients who suffer from HVS. Although we know from other studies that CO2 can play a key role, it might not be necessary to improve anxiety. Breathing slowly and with control (and I personally think control is the key word) appears to promote a sense of mastery and peace that overrides any feeling of anxiety that is produced by hyperventilation.

Abstract from Paper

The effect of breathing therapy was evaluated in patients with hyperventilation syndrome (HVS). The diagnosis of HVS was based on the presence of several suggestive complaints occurring in the context of stress, and reproduced by voluntary hyperventilation. Organic diseases as a cause of the symptoms were excluded. Most of these patients met the criteria for an anxiety disorder. The therapy was conducted in the following sequence: (1) brief, voluntary hyperventilation to reproduce the complaints in daily life: (2) reattribution of the cause of the symptoms to hyperventilation: (3) explaining the rationale of therapy-reduction of hyperventilation by acquiring an abdominal breathing pattern, with slowing down of expiration: and (4) breathing retraining for 2 to 3 months by a physiotherapist. After breathing therapy, the sum scores of the Nijmegen Questionnaire were markedly reduced. Improvements were registered in 10 of the 16 complaints of the questionnaire. The level of anxiety evaluated by means of the State-Trait Anxiety Inventory (STAI) decreased slightly. The breathing pattern was modified significantly after breathing retraining. Mean values of inspiration and expiration time and tidal volume increased, but end-tidal CO2 concentration (FETCO2) was not significantly modified except in the group of younger women (< or = 28 years). A canonical correlation analysis relating the changes of the various complaints to the modifications of breathing variables showed that the improvement of the complaints was correlated mainly with the slowing down of breathing frequency. The favorable influence of breathing retraining on complaints thus appeared to be a consequence of its influence primarily on breathing frequency, rather than on FETCO2.

Journal Reference:

Han JN, Stegen K, De Valck C, Clément J, and Van de Woestijne KP, (1996) Influence of breathing therapy on complaints, anxiety and breathing pattern in patients with hyperventilation syndrome and anxiety disorders, Journal of Psychosomatic Research, 41(5), 481 – 493.