In a notable advancement, a recent study reveals that difficulties at the confluence of the air and food channels may 'overwhelm' the vagus nerve, resulting inPatients with throat difficulties are less able to regulate their blood pressure. 

The study, published in JAMA Otolaryngology recently, is the first to find diminished baroreflex sensitivity in patients with throat complaints. 

The baroreflex is an important component of the autonomic nervous system that detects variations in blood pressure and adjusts our heart rate and blood vessel tone accordingly to keep blood pressure steady. It prevents us from fainting when we stand up. 

Researchers from the University of Southampton and the University Hospitals of Dorset Foundation Trust believe the findings are explained by the Vagas nerve (which controls the autonomic nervous system) prioritising airway protection over less urgent functions like blood pressure regulation. 

"Our immediate survival depends on the throat being able to separate air and food passages each time we swallow," explains Reza Nouraei, Professor of Laryngology and Clinical Informatics at the University of Southampton. 

"The throat does this using delicate reflexes, but when these reflexes are disrupted, for example, by a viral infection like Covid or exposure to reflux affecting nerves in this region, the control of this critical junction is compromised, resulting in symptoms such as a lump in the throat, throat clearing, and coughing." 

"To compensate for a defective throat, the autonomic control system must waste a lot of energy to keep the airway safe. We discovered that in people with a defective throat, the heart, specifically the baroreflex, is less adequately controlled. This is one of the Peters who was robbed to pay Paul. 

"The problem with robbing this Peter is that it likely impacts long-term survival, as patients with reduced baroreflex function are more likely to die of a heart attack or stroke in years to come." 

The researchers compared the heart rates, blood pressure, and baroreflex sensitivity of 23 patients admitted to ear, nose, and throat (ENT) surgery with aerodigestive (laryngopharyngeal) symptoms and 30 patients admitted to gastroenterology with digestive (esophagogastric) symptoms at the University Hospitals of Dorset NHS Foundation Trust. 

Reflux was a significant cause of symptoms in both groups, accounting for the majority of digestive group cases. Other factors, such as vocal cord weakening, were observed in the aerodigestive group. 

The researchers discovered that patients in the aerodigestive group had a faster resting heart rate, lower resting blood pressure, and lower baroreflex sensitivity than those in the digestive group. 

"Now, and especially since Covid, which damages nerves, we are seeing more patients with throat symptoms," adds Prof. Nouraei. 

"Reduced baroreflex sensitivity impacts survival independent of other cardiovascular risks, so if the association we've discovered is confirmed by future studies, the need to make timely and accurate diagnoses and provide early and definitive treatments will become more pressing." 

The work contributes to the growing interest in the Vaus nerve and overall health. In addition to regulating blood pressure via the baroreflex, the vagus nerve regulates our heart rate, digestion, breathing, mood, and a variety of other biological activities that influence our health and well-being. 

Professor Nouraei says, "This study allows us to look at patients more holistically. As a clinician, if you can correct a condition in the throat that is potentially reducing bandwidth from the vagus nerve, you free up the nerve to supply the rest of the body. 

"If there is a chance that throat problems can affect functions like the baroreflex or have a wider impact on overall wellbeing, then they need more consideration," he adds.

The researchers say that they will now investigate the long-term effects of throat issues on autonomic health, as well as the outcomes of treatment.