Kox · Proceedings of the National Academy of Sciences of the United States of America 2014 · randomized controlled trial · n=24

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

Cited 280 times in the scientific literature.

Level 2 - randomized trial

Individual randomized controlled trial

PubMed 24799686 · doi:10.1073/pnas.1322174111 · record verified 2026-08-30

What was done

Twenty-four healthy volunteers were randomized to either an intervention group (n = 12) or an untrained control group (n = 12). The intervention group underwent 10 days of training in meditation (third eye meditation), breathing techniques (cyclic hyperventilation followed by breath retention), and cold exposure (immersions in ice-cold water). All participants subsequently received an intravenous administration of 2 ng/kg Escherichia coli endotoxin to induce experimental endotoxemia while the intervention group practiced the learned techniques.

What was found

The abstract reports directional findings without numerical values. In the intervention group, the techniques produced intermittent respiratory alkalosis, hypoxia, and profoundly increased plasma epinephrine levels. After endotoxin administration, anti-inflammatory cytokine IL-10 levels rose more rapidly, were higher, and correlated strongly with preceding epinephrine levels in the intervention group. Levels of proinflammatory cytokines TNF-alpha, IL-6, and IL-8 were lower and correlated negatively with IL-10. Flu-like symptoms were also lower in the intervention group compared to controls.

Why it matters

This study provides proof-of-concept evidence in humans that autonomic and innate immune responses can be voluntarily modulated, challenging the paradigm that these physiological systems operate entirely outside conscious control.

Limits

The sample size was small (n = 24 total; 12 per arm) and restricted to healthy volunteers under an acute endotoxemia model rather than clinical populations with chronic inflammatory or autoimmune disease. The multi-component design (meditation, breathing, cold exposure) makes it impossible to isolate which element drove the observed effects. The abstract provides no point estimates, confidence intervals, or p-values.

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