Vagus ECG smartwatch

A scientific project that turned into a product

There is broad consensus from scientists that the vagus nerve is one of our most important nerves for immunity and health problems such as anxiety and depression.  Vagal tone is a measurement of the state of the vagus nerve.  Our watch is using unique methods to calculate this vagal tone.

This is the first watch ever that measures breathing. We can therefore correlate breathing to heart rate variations. This correlation is a key component when establishing how well the vagus nerve is functioning.

Our vagus nerve stimulation therapies aim to reduce anxiety and relieve symptoms in a number of currently untreatable neurological diseases such as Chronic Fatigue, Depression, Migraine and Multiple Sclerosis. In Cambridge(UK) and Jinan (China) we are also cooperating with scientists to help autists and speeding up post stroke recovery.


We have now however decided to move ‘step-by-step’ to the consumer market and learn from our first clients, starting with a consumer trial during which we only sell 100 watches. As part of this trial the first 100 who purchase a Vagus ECG Watch will be invited to join the Nerve Explorer initiative. 

THE NERVE EXPLORER - This is where you come in.

The Nerve Explorer is premium analytics and health coaching package for the Vagus Watch.  

We know that each user has personal health-, immune- and nerve-related issues and interests.  With the ‘Nerve Explorer’ concept, we want to work together with our ‘explorers’ to learn and help more people.   The autonomic and central nervous system is the biggest single ‘unknown’ in current scientific research.  Neither we – nor anyone else – can give definite answers for many of its health-related questions.   We though currently live in the golden era of exploration into this ‘white area’ on the map of science.    We hope that together with our ‘explorers’, we can find out more.   Join us in this exciting adventure by collecting data with our Vagus Watch – and let us together learn and enjoy the discovery some of life’s mysteries.

For the 1st 100 Nerve Explorers, our team will personally analyse each users test-data (after 2 months use so that we can see trends), send the conclusions by email and communicate if we find irregularities or special cases which need more ‘exploration’.  We hope that these first 100 explorers will be the arrowhead for a greater movement of crowdsourced science on the autonomic nervous system and specifically the vagus nerve.

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VAGUS NERVE - the heart and breathing

The – ‘Rest & Digest’  – Vagus nerve is the most important nerve you have.  It is more than 10km long and forms the main part of the parasymphatetic nervous system.  It for instance controls the ‘resting-phases’ of the heart and lungs.    The vagus nerves are responsible for the lowering of the heart rate and in the lungs the vagus nerve causes bronchoconstriction to enable efficient oxygenization. A person usually dies quite quickly if the vagus nerve remains in full shutdown.  

When the autonomic nervous system is working normally, the vagus nerve is speeding up the heart rate during inhalation and decreasing heart rate during exhalation. This variation is critically important for optimal oxygenization.  One traditional way to see this vagal tone is by measuring Heart Rate Variability (HRV) but for it to be accurate the measurement should be done for longer times and not by optical heart rate sensors which are inherently inaccurate.    Currently there are also many other indirect forms to quantify this oxygenization with wearable sports- and health devices. 

Finally a watch that measures breathing

The Vagus ECG Watch is the first wearable that can make a much a quick, direct, precise and detailed diagnosis of this interaction between the heart rate and breathing.   Our algorithms can detect breathing from the ECG data by using the Cardiac Brody Effect (1) and with it we then calculate the Respiratory Sinus Arrythmia (RSA) which is considered the best current scientific measurement of vagal tone.   Based on our own scientific research  we have in addition to this RSA, developed a method to detect and diagnose the periodicity of heart rate increases and decreases in relation to each inhale and exhale from hand-to-hand ECG (2).  We call these values the Respiratory Sinus Arrythmia Synchronization (RSAsync, pat.pend).   A person can measure these abovementioned vagal tone values by doing the Vagus Test on our smartwatch.  The test lasts only 90 seconds and it is consider very easy to do since it only involves sitting still while doing some controlled breathing as instructed on the watch screen and holding the right hand thumb on the watch ECG electrode.

(1) ‘The Brody Effect to detect hypovolemia in clinical practice’,  Giraud et al, 2012

(2) ‘Vagal Tone Diagnostics with hand-to-hand ECG’, Study presented by Gustaf Kranck in April 2019 at the BFE conference in Wales. 



The Vagus is tracking most normal sports-watch data such as movement(steps), calories consumed, heart rate(optical sensor), sleep and standing-time.

In addition to these, our ECG-based unique Vagus Heart-Lung AI-Diagnostics gives much additional information for people doing amateur- and professional sports. The Vagus Test is done in only 90 seconds and its prompt analysis of RSA, RSA sync and personalised health indicators are much more exact and up-to-date than traditional HRV. The data is highly correlated with the state of the autonomic nervous system and it gives advice on the person’s ability to sustain longer physical stress and exercise. In our research we have found that 10-15% of the general population have a sub-functioning RSAsync levels and hence a lower than normal oxygenation at time of doing the Vagus Test. These diagnostics parameters should be used by both amateurs and professionals to determine their fitness for prolonged exercise and participation in professional sports.


We believe in open data.   Currently no other smartwatch producer are allowing users to get access to their own ECG measurements as raw data.   For ‘nerve explorer’ clients we will provide this in EDF-format.  Medical professionals can make in-depth analysis of this data.

For clinical trials we provide full data-support in order for the trials to get raw-data access to all data.  In addition to normal database services we can provide blochchain secured data setups.

We are naturally GDPR-compliant and national medical data compliant for hospitals-, pharma- and research clients


The Vagus Smartwatch ECG based unique Vagus Test is a fast and detailed non-invasive and individual health diagnostics.  No other smartwatch has similar features.   The Vagus Test is done in only 90 seconds and its prompt analysis of RSA, RSAsync and personalized health indicators are new types of health indicators.  The data is highly correlated with the state of the autonomic nervous system and it gives advice on the person’s ability to sustain for instance longer physical stress and exercise.   We are currently in the process of applying for EU permission to provide cardiac arrythmia diagnostics. 

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