The ability of organisms to regulate and thus maintain a relatively stable internal environment, despite external pressures, is called HOMEOSTASIS. This word comes from two Latin/Greek root words: "homeo" and "stasis".
"Homeo" means constant or unchanging. And "stasis" or "static" refers to stillness, non-movement. So, together, we can translate Homeostasis into a constant stillness inside, which makes sense for "maintaining normal internal states."
This is referred to as Sleep Apnea.