don't strain too hard while pooping

Excerpted from my physiology syllabus:

Interestingly, the magnitude of intra-abdominal pressures that can be generated during defecation is quite large. This results in an increase in arterial pressure because of increased intra-thoracic pressure transmitted across the wall of the heart and aorta. This, in turn, can decrease venous return and increase peripheral venous pressure because of blockage of the large veins in the thorax. The result is a decrease in systemic arterial pressure by decreased stroke volume and cardiac output. These events can have deleterious consequences in patients with vascular disease. For example, strokes often result from increased pressures in cranial vessels generated by individuals straining to defecate. Heretics who believe that Elvis is dead claim that he died in this manner.

Yeah, the stuff in bold is pretty much all I care to take from that paragraph as well. Such useful things I've been learning.