For everyday stress, breathing exercises are the simplest place to start; heart-rate variability (HRV) biofeedback adds a device-guided feedback signal. Vagus nerve stimulation (VNS) is different: it is a medical intervention, and noninvasive transcutaneous VNS (tVNS) remains experimental for mental health treatment according to the National Institute of Mental Health (NIMH). The evidence summarized here is indirect—no suitable head-to-head trial comparing all three approaches for general stress was identified.
How the three approaches differ
| Approach | What it involves | Equipment or clinical involvement |
|---|---|---|
| Breathing exercises | Deliberately changing the pace or pattern of breathing as a behavioral practice. | Can be practiced without a device; instruction or a guide may be helpful. |
| HRV biofeedback | Using heart-rate information as feedback while practicing breathing, with the aim of changing the heart-rate pattern. | A sensor or other device supplies feedback. The evidence does not show that a particular consumer wearable is effective or necessary. |
| VNS or tVNS | Electrical stimulation of the vagus nerve, either with an implanted device or noninvasively through the skin. | Implanted VNS involves surgery. tVNS is under study; it is not the same as slow breathing or a general wellness “vagus nerve reset.” |
NCCIH describes biofeedback as a process in which a device provides information such as heart rate that a person can use while practicing breathing. That differs from stimulation: breathing and HRV biofeedback train a person’s response, while VNS applies electrical stimulation. NCCIH’s relaxation-technique overview and NIMH’s brain stimulation information describe these distinct contexts.
What the evidence says about breathing for stress
A systematic review by Morgan, Lengacher, and Seo included 19 studies of breathing interventions in adults. Twelve studies reported significant improvements in anxiety and nine reported significant improvements in stress. No adverse events were reported in the included studies, but the authors cautioned that evidence—including large randomized controlled trials—remains limited. The article appeared online on August 16, 2024, and in a December 2025 journal issue. Read the review on PubMed.
A separate 2024 systematic review covered 58 studies and assessed 72 interventions. Its authors found that 54 interventions were effective and associated better outcomes with practices that avoided fast-only pacing and sessions shorter than five minutes, included human-guided training, used multiple sessions, and continued over time. These are patterns found in that review, not a guaranteed formula or universal prescription. Read the review in PubMed Central.
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What the evidence says about HRV biofeedback
A 2017 meta-analysis by Goessl, Curtiss, and Hofmann included 24 studies and 484 participants. It reported Hedges’ g of 0.81 for within-group change from before to after training and 0.83 compared with a control condition. The authors described HRV biofeedback as promising and called for more well-controlled studies. These pooled results describe group-level research; they do not predict an individual person’s response. Read the meta-analysis on PubMed.
For a reader deciding whether to buy equipment, the key distinction is that a heart-rate variability sensor can provide feedback during practice, but a device is not required to try breathing exercises. The cited meta-analysis evaluates HRV biofeedback training, not every consumer wearable marketed for stress or vagus-nerve stimulation.
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What the evidence says about VNS and tVNS
NIMH describes tVNS as experimental for mental health treatment and says questions remain about stimulation sites, parameters, and protocols. It also reports that implanted VNS is FDA-approved for certain adults with severe or recurrent depression lasting at least two years after at least four other treatments, while noting mixed findings about effectiveness. That specific medical use is not an approval for everyday stress. NIMH says tVNS is not currently FDA-authorized as a depression treatment; research is ongoing. See NIMH’s current overview of brain stimulation therapies.
Evidence from other settings should not be overextended. For example, a 2022-issue systematic review of auricular stimulation for preoperative anxiety included 15 studies and 1,603 patients. In eight sham-controlled trials with 701 patients, the authors found lower anxiety scores with stimulation (standardized mean difference −0.72; 95% confidence interval −1.09 to −0.36; moderate certainty), while concluding that more research was needed. Preoperative anxiety is a specific clinical setting, not proof that VNS treats everyday stress. Read the review on PubMed.
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Which option makes sense for everyday stress?
- Start with breathing if you want a low-equipment practice. Adult studies are promising, though the evidence base has limitations.
- Consider HRV biofeedback if a live heart-rate signal would help you follow or refine breathing practice. Treat a device as optional feedback, not as proof that a particular wearable works.
- Do not treat tVNS as an established stress remedy. NIMH characterizes it as experimental for mental health treatment; implanted VNS is a separate medical intervention for specific circumstances.
- Compare evidence for the outcome you care about. The studies discuss different interventions and settings, and there is no direct comparison here showing that one is best for general stress.
Safety and when to stop
NCCIH says relaxation techniques are generally considered safe for healthy people, but some people experience increased anxiety, intrusive thoughts, or fear of losing control. Rare worsening has been reported in people with epilepsy, certain psychiatric conditions, or a history of trauma. If a breathing or relaxation exercise increases distress, stop and seek appropriate support. NCCIH explains potential risks.
Implanted VNS requires surgery. NIMH lists possible issues including infection, device movement or malfunction, voice changes, cough, breathing problems, difficulty swallowing, nausea, and other effects. Reported mild tVNS effects include tingling, pain or itching at the stimulation site, nausea or vomiting, and dizziness. Long-term side effects of VNS forms are unknown. This general information is not a personalized assessment of risk; discuss medical devices and symptoms with a qualified clinician. NIMH provides further safety context.
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