Clinical Autonomic Research

, Volume 6, Issue 4, pp 237–239 | Cite as

Inhibition of muscle sympathetic nerve activity during yawning

  • J. J. M. Askenasy
  • N. Askenasy
Case Report


Yawning is a complex event that depends largely on the autonomic nervous system. Microneurographic techniques were used to study the mechanism involved in yawning. A series of spontaneous yawns displayed by a healthy 39-year-old male offered us the opportunity to study the muscle sympathetic nerve activity (MSNA) during this phenomenon. It was found that 2 s of yawning inhibited the MSNA recorded at the right peroneal nerve in the lateral knee area, while 3 s of slow expiration succeeding a yawn provoked an MSNA discharge. Blood pressure decreased with each slow expiration by 5–6 mmHg, and increased again with the renewed MSNA discharge. We conclude that yawning is associated with a sympathetic suppression that favours a parasympathetic dominance, as indicated by the MSNA and the decrease in blood pressure. The slow expiration following a yawn is associated with a sympathetic activation marked by an MSNA discharge and an increase in blood pressure.


yawning auronomic nervous system microneurography parasympathetic reaction sympathetic discharge 


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Copyright information

© Rapid Science Publishers 1996

Authors and Affiliations

  • J. J. M. Askenasy
    • 1
  • N. Askenasy
    • 2
  1. 1.Sleep Medicine InstituteSheba Medical Centre (affiliated to Sackler School of Medicine, Tel Aviv University)Israel
  2. 2.Department of Internal Medicine EAsaf Harofeh Medical CentreIsrael

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