The Valsalva Maneuver - A Side Effect of Using Sitting Toilets
The Valsalva Maneuver is any attempt to exhale with the mouth and nose closed. Named after the Italian physician and anatomist, Antonio Maria Valsalva (1666-1723), it is also known as Valsalva's Test and Valsalva's Method.
The maneuver is commonly used during some activities:
- Straining to have a bowel movement
- Blowing a stuffy nose
- Certain medical tests or exams
- As a pressure equalization technique by scuba divers, sky divers and airplane passengers
The effect of the Valsalva Maneuver is a drastic increase in the pressure within the thoracic cavity.
The thoracic cavity is the airtight section inside the chest which houses the lungs and heart. In a Valsalva Maneuver, attempting to exhale with the mouth and nose closed increases the pressure in the thoracic cavity because the air cannot escape.
The place where the Valsalva Maneuver is carried out the most is the sitting toilet. It is difficult to evacuate properly on a sitting toilet because the colon is not supported and pressurised. There is also a
kink at the rectum and anus
which obstructs the flow of waste.
The poor user simply have no choice but to strain mightily for bowel movements. This takes the form of holding the breath, and straining and 'pushing downwards' with the diaphragm in an attempt to evacuate waste.
The diaphragm is a thin membrane below the lungs. In normal breathing, during exhalation, it relaxes and pushes upwards into the thoracic cavity to help force the air out of the lungs.
During a Valsalva Maneuver, with the holding of the breath and straining, the diaphragm is forced downwards by the increased pressure inside the thoracic cavity.
The Valsalva Maneuver is dangerous for two reasons. The increased pressure in the thoracic cavity reduces the amount of blood flowing into the thoracic cavity, especially in the veins leading to the right atrium of the heart. The maneuver can also cause cause blood clots to detach, bleeding, irregular heart rhythms and cardiac arrest.
Many of the heart attacks which occur in bathrooms have been linked to the Valsalva Maneuver, which in turn, is closely associated with sitting toilets...
In 1990, Dr B. A. Sikirov, an Israeli physician, wrote an article about the link between heart attacks and sitting toilets [Cardio-vascular Events at Defecation: Are They Unavoidable? - Medical Hypotheses, Jul 1990, 32(3):231-3]:
"Cardio-vascular events at defecation are to a considerable degree the consequence of an unnatural (for a human being) seated defecation posture on a common toilet bowl or bed pan.
Excessive straining, expressed in intensively repeated Valsalva Maneuvers, is needed for emptying the bowels in the sitting position.
The Valsalva Maneuver adversely affecting the cardio-vascular system is the causative factor of defecation syncope (fainting) and death. The cardio-vascular system of a healthy man withstands the intensive and repeated straining at defecation, while the compromised cardio-vascular system may fail, resulting in syncope or even death.
squatting defecation posture
is associated with reduced amounts of straining and may prevent many of these tragic cases."
Also, on a sitting toilet, the straining and pushing downwards with the diaphragm imposes great strains on the colon, pelvic floor, uterus (women), and also important nerves that control the bladder and prostate (men).
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