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Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans

Landmark PNAS RCT (Kox et al., 2014): 10-day training in meditation, cyclic hyperventilation with breath retention, and cold immersion produced voluntary sympathetic activation so that during experimental endotoxemia trained volunteers showed higher epinephrine and IL-10 and lower TNF-α, IL-6, and IL-8 versus controls.

Design

  • N=24 healthy men randomized to 10-day instruction vs no training
  • Bundle: meditation + cyclic hyperventilation / breath-holds + cold water immersions (Wim Hof–style program)
  • Challenge: intravenous E. coli endotoxin (2 ng/kg) with intensive cardiorespiratory and cytokine sampling

Headline outcomes

  • Epinephrine: large acute increases tied to practiced hyperventilation / retention pattern
  • Cytokines: IL-10 rose faster and higher (correlated with epinephrine); TNF-α, IL-6, IL-8 AUCs lower in trained group
  • Symptoms: lower self-reported flu-like symptom scores during endotoxemia

Evidence hygiene

  • This is not the same stimulus as slow 6/min baroreflex training or cyclic sighing mood trials—compare to Balban 2023 (balban-2023-cyclic-sighing-cell-rep-med) and Blades 2024 WHM depression RCT.
  • Bundle confounds cold and meditation with forced hyperventilation; immune endpoints are experimental endotoxemia, not outpatient anxiety scales.

Outcomes

  • immune-modulation
    During endotoxemia, trained participants showed higher IL-10 responses and lower pro-inflammatory cytokine trajectories (TNF-α, IL-6, IL-8) versus untrained controls after the 10-day intervention.
  • other
    Profound voluntary increases in plasma epinephrine during practiced breathing cycles preceding LPS administration.
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