Straining at stool initiates the Straining at stool initiates the .
maneuver that results in a potentially dangerous increase in BP.
maneuver that results in a potentially dangerous increase in BP.

valsalva

Explanation:

Straining at stool initiates the Straining at stool initiates the valsalva maneuver that results in a potentially dangerous increase in BP. This maneuver is a particular way of breathing which increases pressure in the chest. Due to this, there are enormous effects in the body which includes the changes the blood pressure and heart rate.

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permafrost layer, it exists beneath a layer of soil, rock or sediment.