Fibromyalgia and POTS showing up together is far more common than most clinicians realize. In fact, many researchers now think the overlap is not accidental — both conditions involve dysregulation of the nervous system, particularly the autonomic system and pain-processing pathways.

Let’s walk through the biology in plain language.

1. Both Conditions Involve the Nervous System

Fibromyalgia
Postural Orthostatic Tachycardia Syndrome

Fibromyalgia is primarily a pain-processing disorder of the central nervous system, while POTS is a circulation-regulation disorder of the autonomic nervous system.

But these two systems are not separate.

The brain areas that regulate:

• pain perception
  
  
• heart rate
  
  
• blood pressure
  
  
• stress response
  
  

are deeply interconnected.

So when one system becomes dysregulated, the other often follows.

2. Autonomic Nervous System Overactivation

People with fibromyalgia often show excess sympathetic nervous system activity.

That means their bodies stay in a constant “fight-or-flight” state.

Researchers have measured this through:

• elevated resting heart rate
  
  
• reduced heart rate variability
  
  
• abnormal stress responses
  
  

POTS is also largely driven by sympathetic overactivation when standing.

So both disorders often share:

• adrenaline surges
  
  
• poor circulation control
  
  
• fatigue
  
  
• sleep disruption
  
  

One review found autonomic dysfunction in up to 50–70% of fibromyalgia patients.

3. Small Fiber Nerve Damage

Another connection involves small fiber neuropathy.

Small Fiber Neuropathy

Small fibers control:

• pain sensation
  
  
• temperature sensing
  
  
• autonomic circulation control
  
  

Studies have found that 40–50% of fibromyalgia patients show small fiber nerve damage on skin biopsy.

If those nerves are damaged, the body can develop:

• abnormal pain signaling (fibromyalgia)
  
  
• circulation instability (POTS)
  
  

So one type of nerve injury can produce both conditions simultaneously.

4. Poor Blood Flow to Muscles

POTS can reduce blood flow to muscles when standing.

Reduced oxygen delivery can contribute to:

• muscle pain
  
  
• fatigue
  
  
• exercise intolerance
  
  

Those symptoms overlap strongly with fibromyalgia.

Some researchers believe chronic poor microcirculation may contribute to fibromyalgia pain in some patients.

5. Sleep Disruption

Sleep architecture in fibromyalgia is often abnormal.

Researchers see:

• reduced deep sleep
  
  
• abnormal alpha-wave intrusion into sleep cycles
  
  

Sleep deprivation worsens:

• autonomic stability
  
  
• pain sensitivity
  
  
• inflammation
  
  

Which then worsens both fibromyalgia and POTS symptoms.

It becomes a feedback loop.

6. Mitochondrial Stress

Many studies show people with fibromyalgia have reduced cellular energy production.

Mitochondria

Low mitochondrial output can cause:

• fatigue
  
  
• muscle pain
  
  
• nervous system dysfunction
  
  

Autonomic nerves are very energy dependent, so mitochondrial stress can worsen dysautonomia.

7. Inflammation and Immune Activation

Low-grade inflammation is common in fibromyalgia.

Elevated markers have been observed including:

• IL-6
  
  
• IL-8
  
  
• TNF-alpha
  
  

These inflammatory signals can affect:

• nerve sensitivity
  
  
• autonomic signaling
  
  
• pain thresholds
  
  

Some POTS cases also appear to involve autoimmune activity affecting autonomic receptors.

8. Why It Often Appears After Stress or Illness

Both conditions frequently appear after:

• viral illness
  
  
• surgery
  
  
• trauma
  
  
• chronic stress
  
  
• long-term sleep disruption
  
  

Those events can destabilize the autonomic nervous system and pain signaling pathways simultaneously.

What This Means Practically

For someone like Marie who has:

• fibromyalgia
  
  
• POTS
  
  
• poor sleep
  
  
• past surgeries
  
  
• long dieting history
  
  

the goal is not chasing symptoms individually.

Instead, the strategy is stabilizing the systems that affect both:

Key targets

• nervous system balance
  • circulation
  • sleep quality
  • mitochondrial energy
  • inflammation
  • muscle strength

When those systems improve, both fibromyalgia and POTS symptoms often improve together.

Encouraging Reality

These conditions can feel overwhelming, but the nervous system is plastic.

With consistent support through:

• proper nutrition
  
  
• gradual movement
  
  
• sleep repair
  
  
• stress regulation
  
  

the body can often regain significant stability over time.

References

Clauw DJ. Fibromyalgia: A clinical review. JAMA. 2014.
Oaklander AL et al. Objective evidence that small-fiber polyneuropathy underlies some illnesses currently labeled as fibromyalgia. Pain. 2013.
Raj SR. Postural tachycardia syndrome (POTS). Circulation. 2013.
Martínez-Lavín M. Fibromyalgia and the sympathetic nervous system. Arthritis Research & Therapy. 2012.