MEDICAL MATTERS:Do you sneeze after sex? No, not snooze, but sneeze. It sounds most odd but there is a growing amount of medical literature linking sneezing with orgasm and even with thinking about sex.
Researchers are quick to point out that there is no link between post orgasmic sneezing and any form of psychiatric illness.
They say the phenomenon is much more common than expected and speculate it may be caused by stimulation of the parasympathetic nervous system.
Reflex
Sneezing is a reflex that has developed to clear the nasal passages of particles, infectious material and other irritants. Despite being a widespread phenomenon, comparatively little is known of the neurological pathways involved in the reflex.
In the human brain the lateral medulla, located close to the spinal trigeminal tract, is thought to be the likely location of the sneezing centre.
Apparently, eyebrow plucking, which involves the stimulation of non-nasal branches of the trigeminal nerve, can trigger sneezing.
There have also been reports of two families who reflexly sneeze after meals. And I am one of about 25 per cent of the population who sneeze after looking at sunlight.
However, this phenomenon cannot be linked with trigeminal nerve stimulation and is known as a photic sneeze reflex. Of course some bright medic couldn’t resist coming up with a suitable acronym for this and so we have the Achoo syndrome: the autosomal dominant compelling helio-ophthalmic outburst syndrome (autosomal dominant is a reference to the apparent genetic inheritance of the trait).
The link
But what could be linking the nasal and genital areas in humans? In the late 1800s a Dr Fleiss, a close friend of Freud, developed his theory of “nasal reflex neurosis”. He suggested the existence of erectile tissue in both the nasal and genital membranes. But he was never able to explain how the erectile tissue of these distant sites was linked.
After he developed a somewhat fanciful theory linking the nose with menstruation, his ideas were discredited.
Stimulation of the body’s parasympathetic system seems the most likely explanation for the phenomenon. All of the reported triggers of sneezing that arise independent of a nasal trigger have parasympathetic outflow as a common variable.
For the photic sneeze response, there is parasympathetic activity that leads to constriction of the pupil in response to light. When the stomach is full, there is parasympathetic activity to stimulate movement through the stomach and acid secretion.
When there is sexual ideation, there is parasympathetic outflow to cause venous dilation leading to penile erection or clitoral tumescence. At orgasm there is also parasympathetic activity to bring about secretion from glands producing components of male or female ejaculate.
As yet there is no anatomical explanation showing how nerves in the nose are linked to nerves in the penis or clitoris.
The best scientists can come up with is some genetically induced fault in the development of the parasympathetic nervous system in the embryo.
As various researchers point out, the phenomenon of sneezing after sex does not cause disease and so there is no need for those who experience it to see a doctor.
In addition it is socially embarrassing which is another reason why it is probably under-reported.
One group carried out a search of internet chat rooms in 2007 and found 17 people of both sexes who experienced sneezing after thinking about sex and three people after orgasm.
While acknowledging the non-scientific basis for their research, they said: “It appears the sneezing occurs immediately upon sexual ideation, or very soon after orgasm. It also seems that the two phenomena do not occur in the same person, ie that these are two distinct entities: sneezing with sexual ideation or sneezing with orgasm.”
Sneezing after sex opens up the possibility of a whole new post-coital dialogue. Although it has to be said that “bless you” sounds a lot less seductive than “how was it for you, darling?”
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mhouston@irishtimes.com