Investigating Physiological Wellbeing In Patients With Functional Disorders


Clinical investigations like CT, MRI, ultrasound, blood and urine tests, are organ focused, but in the usual cross specialty clinical case-mix, there are many patients in whom “hardware” examination like this fails to explain symptoms.

Prime examples include chronic fatigue, long Covid, brain-fog, functional dyspepsia, IBS, micturition urgency and frequency, fibromyalgia, hyperventilation, functional tachycardia, headache and a range of “functional” gynaecological symptoms.

The vagus nerve is the body’s information highway, with 80% of its fibres carrying afferent information and only 20% relaying efferent instruction. Connected to all the major viscera, this neural network asserts a braking effect on the always loaded sympathetic nervous system and, with specialised sensing of end organs, constantly monitors inner wellbeing (interoception). While the sympathetic system mediates flight or fight, the parasympathetic network oversees rest, restore and digest.

Wellbeing is associated with appropriately modulated autonomic balance. There is considerable evidence that loss of vagus tone and abnormal afferent signalling contributes to a spectrum of “functional” disorders, and it is now possible to assess vagus tone by monitoring heart rate variability (HRV) providing a window to visualise autonomic balance and physiological wellbeing.

Taking investigations one step further

Across primary and secondary care, investigating HRV takes clinicians beyond “hardware”, into the patient’s “software” domain. When hardware investigation fails to explain the patient’s symptom complex, demonstration of impaired autonomic balance may provide further understanding of previously unexplained symptoms.


Our HRV Assessment test

Bodyguard2, a lightweight wearable device, provides a well validated measure of HRV and vagus tone over a 72-hour assessment period. The output and report is presented as a clear, colour-coded graphical display, to illustrate:

  • The brain-visceral axis
  • The state of physiological stress and wellbeing
  • Physical fitness (VMaxO2 can be accurately derived from HRV)


  • Bodyguard2 is easy for patients to fit and easily worn.
  • The device can be delivered direct to patient’s home and returned by post.
  • Continuous HRV monitoring takes investigation a step beyond visceral “hardware” providing clinicians and patients with diagnostic insights into the spectrum of functional “software” disorders often encountered in clinical practice.
  • Assessing the body’s information superhighway opens a new window for diagnosis and management.

For more details or to arrange a Bodyguard2 HRV investigation, please contact us via


If the result is abnormal, we can advise targeted treatment options, including:

  • Non-invasive transcutaneous vagus nerve stimulation (nVNS)
  • Autonomic focused medical hypnosis
  • Counselling

Watch the videos

HRV and assessing physiological well-being HRV

nVNS and IBS

Our survival software

(Photos and videos courtesy of Firstbeat and MIGe Diagnostics Lab)

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