Inhibition of muscle sympathetic nerve activity during yawning

Clin Auton Res. 1996 Aug;6(4):237-9. doi: 10.1007/BF02291140.


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.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Blood Pressure / physiology
  • Humans
  • Male
  • Microelectrodes
  • Muscle, Skeletal / innervation*
  • Muscle, Skeletal / physiology
  • Parasympathetic Nervous System / physiology
  • Respiratory Mechanics / physiology
  • Supine Position / physiology
  • Sympathetic Nervous System / physiology*
  • Yawning / physiology*