The Invisible Shake: Internal Tremors May Signal More Severe Long COVID, Study Finds

For many long COVID patients, the road to recovery is filled with fatigue, brain fog, and shortness of breath. But for some, there’s a strange and deeply unsettling symptom that’s often misunderstood, even by doctors: internal tremors.

Now, a new study published in the American Journal of Medicine confirms what many patients have been saying for years. These invisible vibrations are real and may indicate a more severe form of long COVID.

What Are Internal Tremors?

Internal tremors feel like a buzzing, shaking, or vibrating sensation inside the body. Unlike classic tremors, they’re not visible from the outside, and they don’t always involve muscle spasms or involuntary movement.

These sensations may be felt in the chest, back, limbs, head, or throughout the body, and can be persistent or come and go. While not life-threatening, they can be terrifying, disruptive, and exhausting.

What the New Study Found

In the study, researchers surveyed 423 adults with long COVID between May 2022 and June 2023. Of these, 37% (158 people) reported experiencing internal tremors or vibrations. The majority were female (74%) and White (87%), with a median age of 46.

The findings? People who experienced internal tremors had:

• A lower quality of life, with a median score of 40 vs. 50 (out of 100) on the Euro-QoL scale

• Higher rates of new-onset neurologic conditions (22% vs. 8.3%)

• More mast cell activation disorders (11% vs. 2.6%)

“These symptoms may reflect a particularly severe phenotype of long COVID,” the researchers concluded. They called on clinicians to be more aware of internal tremors when evaluating long COVID patients.

What Could Be Causing This?

While researchers haven’t pinpointed a single cause, they suggest possible links to:

• Dysautonomia – dysfunction of the autonomic nervous system

• Peripheral nerve damage or inflammation

• A connection to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), which shares overlapping symptoms with long COVID

Previous studies have described internal tremors mainly in people with Parkinson’s disease or essential tremor. But, only a handful have looked at this symptom in the context of long COVID until now.

Why This Matters

Internal tremors can severely affect a person’s daily life, even if they can’t be seen. They’re often accompanied by:

• Trouble sleeping

• Increased anxiety

• Difficulty concentrating or performing tasks

• Physical discomfort and fatigue

And yet, many doctors have dismissed or misdiagnosed patients.

The study’s authors say it’s time for the medical community to treat internal tremors as a serious long COVID symptom, not just a side note or psychological complaint.

What You Can Do

If you’re experiencing internal tremors or buzzing sensations after a COVID-19 infection, here’s what you can do:

Track your symptoms – Note frequency, triggers, and how it feels

Describe it clearly to your doctor – Even if it sounds “weird”

Ask for a referral to a neurologist or specialist familiar with long COVID

Look into dysautonomia screening if symptoms involve heart rate, dizziness, or fainting

Join a support group – Sharing with others helps validate your experience

You are not imagining things, and you’re not alone.

Looking Ahead

As researchers uncover more about the long-term effects of COVID-19, this study validates patients whose symptoms doctors have long overlooked. While internal tremors remain poorly understood, this research begins to shift how the medical community recognizes and investigates their impact.

The takeaway? Invisible doesn’t mean insignificant. And with more awareness, we can move closer to understanding and treating this challenging condition.

References:

• Am J Med 2025;138:1010-1018.E14

• BMJ Open 2023;13:e077389

• Nat Med 2023;29:226–235

• Compr Physiol 2014;4:805–826

• Neurology 1995;45:565–568