Klarinet Archive - Posting 000402.txt from 1998/08

From: "Diane Karius, Ph.D." <dikarius@-----.edu>
Subj: Re: [kl] The Valsalva Maneuver and Heart Stoppage
Date: Fri, 14 Aug 1998 11:11:14 -0400

> >>Not to be too delicate about it, the Valsalva maneuver is the complex
> series of muscle contractions we use in defecating. <<
>
> Huh? When I was in the Air Force we had to perform the valsalva maneuver
> every year during our annual flight physical. You hold your nose and mouth
> closed and "blow" while the doctor looks in your ears.

They are the same thing in mechanics (degree is something else) -
both generate positive (i.e. greater than atmospheric) pressure in
the thorax and abdomen. The decrease in heart rate mentioned in the
original article is at least partly due to a vagal (vagus nerve)
reflex that is activated by the effect of the pressure on the return
of blood to the heart through the veins (Bainbridge reflex).
Diane R. Karius, Ph.D.
Department of Physiology
University of Health Sciences
1750 Independence Ave.
Kansas City, MO 641o6-1453
email: dikarius@-----.EDU

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