Eight hours has long been touted as the gold standard of sleep time, but this number is an average: Most people need seven to nine hours. Some can get by on four hours a night, but others need as many as 12. The majority of people who claim to need next to no sleep seem to have a lack of self-awareness rather than a superior ability to function.
There's very few people who can consistently get less than four hours of sleep and function during the day.
When many people who claim not to sleep during the night are observed in a sleep lab, parts of their brain shut down, so although they are no longer fully conscious, they might believe they are.
There remains some controversy over whether people need less sleep as they get older. What is clear is that they tend to get less sleep with age. It's not that people need less sleep as they age, but they have difficulty sustaining sleep for as long as they did when they were younger.
The number of hours of sleep may decline some in old age only because sleep fragments with more awakenings at night and begins to intrude into catnaps during the day. The total hours in 24 is still the same.
The weekends can be (and typically are) used to help catch up on sleep lost during the week, but catching up needs to be done in a specific way to avoid disrupting sleep patterns. Using the weekends to sleep in an extra hour or two might be a good way to catch up on lost sleep, assuming one isn't too far behind on sleep to begin with.
The problem, however, is that typically people stay up later on the weekends and then sleep in, which throws off the entire rhythm of the sleep cycle.
Sunday night insomnia results from oversleeping Sunday morning, so you are trying to fall asleep at too early an hour that night.
Does having sex before bed allow people to destress and fall asleep easier, or does it simply make them more alert and less able to sleep? Researchers had a number of explanations for how sex might affect sleep. Sex may help some sleep by calming them down before bedtime. Alternately, it may keep them awake, particularly if it is not enjoyable. Surprisingly there’s not a lot of evidence to answer this question well. As with exercise, people just have to experiment on their own.
Scientific literature on sleep does not show any evidence that Freddy Krueger can kill you by invading your dreams. However, the idea for the film seems to come from a real-life phenomenon linked to a real-life murderous villain.
In the 1970s, millions of Cambodians were killed by Pol Pot's Khmer Rouge regime. Some refugees fled to the United States, and it was observed that some young men were reluctant to sleep -- and some died from heart attacks while sleeping.
Originally attributed to nightmares because of what they'd experienced, the deaths were not restricted to Cambodian refugees. Since that time, evidence has accumulated that sleep deaths resulted from a genetic heart condition called Brugada syndrome.