Respiratory Symptoms

1 Dyspnea and Air Hunger

Clinical Presentation.

  • Shortness of breath at rest or with minimal exertion
  • Sensation of not getting a β€œsatisfying” breath
  • Need to consciously focus on breathing
  • Air hunger not relieved by deep breathing
  • Normal oxygen saturation (SpO2) during symptoms

Mechanism. Dyspnea in ME/CFS typically reflects problems with oxygen delivery and utilization rather than oxygen intake. Contributing factors include:

  • Autonomic dysfunction (vagus nerve signaling errors)
  • Microcirculatory failure (oxygen cannot reach tissues)
  • Preload failure (blood pooling prevents adequate cardiac output)
  • Respiratory muscle weakness
  • Dysfunctional breathing patterns (loss of diaphragm-chest synchrony)

2 Dysfunctional Breathing Patterns

Clinical Presentation.

  • Loss of synchrony between chest and abdominal breathing
  • Overuse of accessory muscles (neck, shoulders)
  • Shallow, rapid breathing
  • Breath-holding or irregular breathing rhythm
  • Exertional breathlessness disproportionate to activity

Mechanism. A 2025 study found 71% of ME/CFS patients have β€œhidden” breathing abnormalities. Using accessory muscles instead of the diaphragm consumes 3\(\\times\) more energy, worsening fatigue.

3 Chronic Cough

Clinical Presentation.

  • Persistent dry cough without infection
  • Throat irritation or tickle sensation
  • Cough worsening with exertion, talking, or breathing cold air
  • May be related to GERD, postnasal drip, or airway hypersensitivity