The correct answer is informal
After 72 hours without sleep, most people experience an overwhelming urge to sleep. Many are unable to stay awake on their own. Going three days without sleep profoundly limits the ability to think, especially executive functions such as multitasking, remembering details, and paying attention.
why?
because it has set its self in survival mode.
7 days? idk but heres the effects
If you continue to operate without enough sleep, you may see more long-term and serious health problems. Some of the most serious potential problems associated with chronic sleep deprivation are high blood pressure, diabetes, heart attack, heart failure or stroke
If you have had sex you should get checked. but some peoples periods arent regular all the time
