Speculation--it may compress and therefor adversely affect the area postrema--the area postrema red button gets pushed, and ya wanna puke...
"due to compression of the area postrema cells, based upon a mechanism analogous to that of the muscle spindle fiber cells class 3.254beta 5, there is an upregulation of NaPUK2 receptors, which leads to an influx of antigraviton zeta ions, creating conditions favorable for a downregulation NaPUK3 receptors, which in turn causes increased transcription of forkulon gorko found on the third leg of chromosome 6..."