Wearable vibrating gadgets are being hailed on TikTok as a cure for chronic stress. The devices \u2014 bracelets, pendants, neck collars and ear pieces \u2014 perform \u201cvagus nerve stimulation\u201d (VNS), which, TikTokers claim, is the secret to switching your nervous system to calm. It sounds quite a lot like wellness claptrap. Is it?<\/p>\n
The vagus is the longest cranial nerve in the body, connecting the brain with all the main organs \u2014 the heart, lungs, stomach, intestines, liver \u2014 and conveying information in both directions. Imagine it as a bit like a tree, with two nerves running down both sides of your neck, each with 100,000 fibres, branching out into almost every part of your body. It influences functions from our heart rate to our mood, sexual arousal and digestive health.<\/p>\n
One of its biggest jobs is to help regulate our stress response. The vagus nerve is part of our autonomic nervous system, which has two parts: the sympathetic nervous system (SNS) \u2014 responsible for the heightened anxiety of \u201cfight or flight mode\u201d \u2014 and the parasympathetic nervous system (PNS) \u2014 associated with \u201crest and digest\u201d when we\u2019re calm. The two should be in balance, like a set of scales. But in our relentless modern lives the SNS can dominate, locking us in a stress loop, our brains not having evolved to separate the perceived threat of an irate WhatsApp message from being attacked by a lion. <\/p>\n
\u2022 Julia Bradbury: I\u2019ve tried every health hack \u2014 here\u2019s what works<\/a><\/p>\n That\u2019s where vagus nerve stimulation comes in. If our SNS is heightened, the brain reduces the number of signals going through the vagus. Once we feel more relaxed, the vagus is turned back up. \u201cIt\u2019s thought that if we enhance its activity, then we may well be able to enhance the parasympathetic side and tilt the scales in that more relaxing direction,\u201d says Hamish McAllister-Williams, professor of affective disorders at Newcastle University. <\/p>\n Surgically implanted VNS devices can help people with treatment-resistant depression. One study by Washington University School of Medicine found the devices had a significant impact on symptoms and quality of life. But what about VNS devices that offer non-invasive stimulation through the skin? These include gadgets such as the Nurosym (\u00a3599), which clips on to the ear, or the Pulsetto (from \u00a3542), which sits around the neck, both of which release gentle electric pulses. \u201cWe have much less evidence for their effectiveness,\u201d McAllister-Williams says. The same goes for exercises such as deep breathing or humming, which are often promoted online as having the ability to stimulate the vagus nerve, but for which there is limited science. <\/p>\n