Relief for long COVID fatigue: Resetting the vagus nerve

In January 2023, the number of people in the U.S. currently experiencing long COVID symptoms declined to 11 percent from 19 percent six months earlier. The drop-off is good news, but that’s still a significant number of people suffering from what can be a debilitating condition.

People with long COVID often experience persistent fatigue that’s so profound, in one study, almost half of patients reported it decreased their quality of life. And another study found that even if a person’s case of COVID had been relatively mild, they could still develop chronic fatigue syndrome.

Investigators are striving to figure out what exactly it is about COVID that leads to this type of long-range fatigue — and most importantly, how to relieve it. A research team in the U.K. may have hit a nerve…

Underactivity in the central nervous system

The Newcastle University researchers conducted behavioral and neurophysiological tests on a group of 37 volunteers with post-COVID fatigue. Then, they compared the results with those of 52 control subjects. The tests included a startle reaction time test, an electrocardiogram and transcranial magnetic stimulation.

What they found in patients with post-COVID fatigue was eye-opening:

• There was underactivity in certain cortical circuits that caused a slower reaction in specific areas of the brain.
• There was also impairment in the autonomic nervous system, the network of nerves that regulates unconscious bodily functions such as blood pressure and breathing rate. This impairment can have wide-ranging effects on several different body processes.
• There were abnormalities in muscle fibers that caused them to become more easily fatigued after exercise.

This breakthrough has given them a lead on a possible therapy…

Research Assistant Natalie Maffitt, co-author on the paper, said: “Following on from these findings, we are beginning testing at Newcastle University on whether the autonomic nervous system can be modulated to improve symptoms in post-covid fatigue.”

And to do that, their focus is on stimulating the vagus nerve, an integral part of the autonomic nervous system…

Resetting the vagus nerve to treat Long COVID fatigue

Based on previous research into chronic fatigue conditions, the Newcastle team believes stimulating the vagus nerve might relieve the fatigue of long-COVID.

But there’s another connection as well: upper respiratory viral infections have been known to trigger dysfunction of the vagus nerve.

The vagus nerve is a cranial nerve that begins in the part of the brain that connects to the spinal cord, but it splits off into many “branches,” first extending down either side of the neck, then through the heart, around the lungs, through the abdomen and into the intestines.

The far-reaching nerve provides nerve signals to various parts of the body — and one of those is the ears.

“We’re examining a non-invasive method which involves clipping an earpiece to the tragus on the ear and delivering small electrical currents to the vagus nerve using a TENS machine…,” says Maffitt.

Stimulating the vagus nerve

Researchers have previously turned to stimulation of the vagus nerve to relieve symptoms of numerous conditions including epilepsy, inflammatory bowel disease, gastroparesis, vasovagal syncope (fainting) and treatment-resistant depression.

And because the nerve affects multiple body systems, many symptoms can indicate vagal nerve dysfunction, including acid reflux, abdominal pain and bloating, dizziness, hoarseness, unexplained weight loss, chronic mood disorders and more.

If I had to guess, I’d say the Newcastle team is on the right track. In 2019 researchers at the University of Leeds recruited volunteers, aged 55 and up, and gave each of them tVNS (transcutaneous vagus nerve stimulation) therapy via the ear for 15 minutes a day for two weeks.

Participants not only showed an increase in parasympathetic activity and a decrease in sympathetic activity, which demonstrated a rebalancing of their autonomic nervous systems, but also reported improvements in their mental health and sleeping patterns.

It’s not sure when tVNS might be widely available as an official therapy for long COVID. But portable TENS units are safe and affordable for home use and rather low-priced on sites like Amazon.com.

If a little ear tickle is not your preferred method to improve fatigue that could be related to long COVID, there are other ways the nerve might be stimulated.

Also, a previous study found that long COVID patients given a combination of L-arginine and liposomal vitamin C experienced less fatigue.

Sources:

Unlocking the secrets of long Covid — Newcastle University

Neural dysregulation in post-COVID fatigue — Brain Communications

Long COVID: What Do the Latest Data Show? — KFF

Global prevalence of chronic fatigue syndrome among long COVID-19 patients: A systematic review and meta-analysis — BioPsychoSocial Medicine

TENS (transcutaneous electrical nerve stimulation) — NHS