Whether sleep deprivation can kill is somewhat debatable. That’s because people who forgo sleep for extended periods of time may also use a lot of stimulants from the benign coffee to the more dangerous types of drugs, such as cocaine and methamphetamine. So, it can be difficult to single out a person’s cause of death in fatalities that involve sleep deprivation.
…[However,] the detrimental effects of sleep deprivation appear after just 24 hours of no sleep, such as rising stress hormone levels, which raises blood pressure.
After two days of no sleep, the body’s ability to turn glucose into energy is diminished and the immune system stops working as well as it does when fully rested. The body’s internal temperature also begins to sink.
By day three, cognitive abilities are profoundly impaired, especially short-term memory and executive functions such as paying attention and multitasking.
While sleep deprivation may not kill you on the spot, it has been linked to a greater risk of diabetes, obesity, depression, heart conditions, and other health problems. Luckily, our bodies have pretty good defense mechanisms that help most people avoid insufficient slumber. By making us lack energy, feeling groggy, and generally miserable, the body sends a clear message: ‘please sleep!’