Lack of sleep has the same cognitive impact as drunkenness

In one study from the University of Pennsylvania, researchers split a test group of people up into three categories; for 14 days, one group slept for eight hours a night, the second group slept for six hours a night, and the third group slept just four hours a night. Cognitive tests after the fortnight period showed those that had had six hours sleep a night showed a similar reaction time as people whose blood alcohol content was at 0.1 percent - in other words, the equivalent of being legally drunk.

The four hour sleep group showed even more dramatic symptoms of sleep loss, occasionally even falling asleep during their cognitive tests.

Sleep deprived people aren't aware of how sleep deprived they are

While short-term sleep deprivation can be addressed by a few good night's sleep, if the period of deprivation lasts over a period of months or years, it's unknown whether brain function can be fully repaired or whether it is permanently impacted. But with chronic sleep deprivation, researchers have found that how sleepy you feel does eventually level off, meaning that, alarmingly, you become less and less aware of your own impairment through sleep deprivation over time.

Less than seven hours a night leads to a 12% higher risk of death

Apart from cognitive issues, individuals who consistently sleep less than seven hours a night have an increased risk of heart disease, obesity and diabetes - not to mention a 12% higher risk of death. On the other hand, studies have shown that while sleeping more than eight hours a night does not impair brain function, it also carries an increased risk of heart disease, obesity and diabetes and a shocking 30% increased risk of mortality. So, needless to say, too much sleep can be unhealthy too.

However, the video also noted that genetics play a role in how much sleep your body needs per night, with some people able to thrive on six hours' sleep thanks to a mutation of a specific gene.

Find out more out the importance of sleep and how many hours you need per night by watching the video, below:

How much sleep do you really need? Terrifying video highlights the effects of sleep deprivation on brain function