So if «vagus nerve techniques» don’t actually stimulate the vagus nerve…

As a follow-up to my post on polyvagal theory I feel the urge to elaborate. The mental health and wellness bubble is awash with “educational” posts, reels, even courses on “how to stimulate your vagus nerve”, always accompanied by countless anecdotes of healing and recovery.
And sure, the techniques may work for some, and if they worked for you, that’s brilliant and you should keep doing what you’re doing. I do wonder whether you’d consider the following before claiming that you are “stimulating your vagus nerve”:

When I hear the term “stimulation”, I assume that we are talking about an action that has direct, electrical or mechanical effects on a structure. Like strumming a guitar chord, or applying electrical pulses to a nerve, increasing its activity as a result. And this can be done on the vagus nerve: certainly with vagus nerve implants that work as pace makers and have shown promise in the treatment of e.g. epilepsy and treatment resistant depression, or through transcutaneous stimulation (though this is still in early stages – going to reserve judgement on that. And don’t buy a vagus nerve stimulator!!).

However, the term “vagus nerve stimulation” is big in the wellness space at the moment. From meditation to humming to yoga, to social interaction, even foot tapping – I have seen them all advertised as “stimulating the vagus nerve”. And if I wanted to be really lenient here, I could certainly say, ok – these techniques might have a calming effect, so they might increase parasympathetic activity, involving the vagus nerve, so I suppose we could kind of, sort of, say they stimulate the vagus nerve because it might be more active during or as a result of these techniques.

But I’m not that lenient and it feels to me like trickery to say it that way because that increase of the parasympathetic nervous system, on the basis of my training and expertise, is much more likely to be the result, not the driving mechanism of these techniques.

So here’s what I think is behind the potential effectiveness (whether clinical or anecdotal) behind these techniques.

Focus.

Here’s the thing about our brain. It can only ever consciously focus on one thing (that’s why multi-tasking is a myth (e.g. Kucyi et al., 2017)). When we find ourselves in unpleasant states, whether it be high arousal such as stress or anxiety, or low arousal such as depression (all “nervous system states” often targeted by “vagus nerve practitioners”), we tend to engage in something called “rumination” – repetitive thought cycles that feel like analysis and reflection but actually tend to confirm our beliefs and attitudes related to our internal state and therefore work to maintain it (e.g. Nolen-Hoeksema, 2000). That means, we are focussing intensely on these unhelpful thoughts.

Doing something that shifts our focus, then, might just help interrupt that cycle and bring momentary relief – and, with practice (and probably, in the case of psychological disorder, with help from a licensed professional), give us a chance to step back and try and evaluate our unhelpful cycles. Over time, these practices might also increase our ability to catch and disengage from unhelpful thoughts earlier, potentially facilitating recovery (but let me stress again - it is extremely unlikely that recovery will be the result of these practices by themselves).

So how do these techniques shift our focus, and how do they have the potential to hold it? I think there might be two main mechanisms – sensory perception and difficulty.

Most of the suggested techniques involve either or both of these components: Breathing techniques are just slightly difficult because we have to become aware of something we don’t usually pay any attention to, our breath, to then adjust it to certain parameters. This requires continuous focus so we don’t drift back into our habitual breathing. It’s also, in itself, a form of meditation, or at least mindfulness. Meditation, then, often combines this with a focus on the physical sensations of the breath and attempts to disengage from any thoughts that come up. Yoga adds postures that are difficult, often because they induce sensations of stretch or challenges to balance. Even tapping techniques involve focus because practitioners are urged to stick to certain repetitive patterns and often also repeat affirmations or mantras. All of this will shift our focus off the self-perpetuating cycle of unhelpful thoughts that helps to maintain how we feel and give us a break from it and, maybe become a little bit calmer or happier. And that has also been shown in studies

I can’t write about the widely advertised techniques of meditation, breathwork, yoga and the like without mentioning, however, that, although often advertised as such, they are not a one-stop-shop for “healing”, have been criticised, and although studies have been conducted, many of them come with limitations (see Sedlmeier et al., 2012). What wellness influencers often fail to mention is that they can have adverse effects, including a worsening of symptoms, depersonalisation or even hallucinations (Goldberg et al., 2022; Lambert et al., 2023; Taylor et al., 2022). So you might want to be aware of this before you try them and stop if you feel they are making you feel worse than you did before in any kind of way.

Goldberg, S. B., Lam, S. U., Britton, W. B., & Davidson, R. J. (2022). Prevalence of meditation-related adverse effects in a population-based sample in the United States. Psychotherapy Research, 32(3), 291–305. https://doi.org/10.1080/10503307.2021.1933646

Kucyi, A., Hove, M. J., Esterman, M., Hutchison, R. M., & Valera, E. M. (2017). Dynamic Brain Network Correlates of Spontaneous Fluctuations in Attention. Cerebral Cortex, 27(3), 1831–1840. https://doi.org/10.1093/cercor/bhw029

Lambert, D., van den Berg, N. H., & Mendrek, A. (2023). Adverse effects of meditation: A review of observational, experimental and case studies. Current Psychology, 42(2), 1112–1125. https://doi.org/10.1007/s12144-021-01503-2

Nolen-Hoeksema, S. (2000). The role of rumination in depressive disorders and mixed anxiety/depressive symptoms. Journal of Abnormal Psychology, 109(3), 504–511.

Sedlmeier, P., Eberth, J., Schwarz, M., Zimmermann, D., Haarig, F., Jaeger, S., & Kunze, S. (2012). The psychological effects of meditation: A meta-analysis. Psychological Bulletin, 138(6), 1139–1171. https://doi.org/10.1037/a0028168

Taylor, G. B., Vasquez, T. S., Kastrinos, A., Fisher, C. L., Puig, A., & Bylund, C. L. (2022). The Adverse Effects of Meditation-Interventions and Mind–Body Practices: A Systematic Review. Mindfulness, 13(8), 1839–1856. https://doi.org/10.1007/s12671-022-01915-6