Mr. Sandman, bring me a dream.

It’s a popular song from the mid-20th century that you’ve probably heard in various films or television shows, and is based on a European mythical character who puts people to sleep and encourages them to dream by sprinkling sand in their eyes. 

Sleep, long regarded as a necessary human function, has snuck its way into our popular media and culture, jokes, dialogue and song, but we still believe in many falsehoods and myths about it. By doing away with these 10 misconceptions about sleep, you’ll rest much better.

You can pull an all-nighter to study and do just as well as you would have otherwise

False. You’ve probably heard this one before, but research studies have found that with sleep deprivation, performance actually suffers, especially with the more all-nighters you pull. You would actually be better off studying consistently than all in one night and losing sleep. In addition, the brain requires sleep to consolidate new memories after learning. Sleep spindles, a pattern of brain activity that occurs during the second stage of nondreaming sleep, refresh the ability for new learning each night. So if you stay up all night reading your textbook and expect to remember facts for your midterm, you’d be better off studying daily than in one night.

Alcohol makes you sleep better

Not necessarily true. Yes, alcohol can make you sleepier, but it can also disrupt sleep later in your sleep cycle. Alcohol also causes really weird dreams, as some of you may have experienced. Because alcohol suppresses rapid eye movement, or REM, sleep — the sleep stage where humans dream — drinking alcohol before bed can also cause memories to not be processed by sleep or retained, even several nights later. That’s why your memories of the night can just … black out after a certain number of shots.

Getting six to seven hours of sleep is enough

No, six to seven hours of sleep is not enough, unfortunately. There’s a reason doctors recommend that you get seven to nine hours. Losing out on one to two hours of sleep can be as bad as not sleeping at all in terms of attentional lapses and performance. Between getting seven hours of sleep and getting nine, you may not feel any different, but there is definitely a marked difference in your work and results.

Older adults sleep more

This is, once again, actually false. The older you get — especially as you approach 75 years of age or older — the less sleep you have that is slow-wave, or part of the first two stages of the sleep cycle. You will also have an increased number of awakenings through the night and less REM sleep, meaning your overall quality of sleep will go down. So really, older adults sleep less, not more. Enjoy the amount of sleep you have now and take advantage of being young.

Your brain will catch up on sleep later

You might have stayed up one night thinking that you’ll just get good sleep the following night, but sadly, it doesn’t work that way. You don’t really ever get back the sleep you’ve lost. Studies have shown that people don’t recover from partial, chronic sleep deprivation even after several nights of recovery sleep.

It doesn’t matter when you sleep

It actually does matter when you sleep, because chronic disruptions in the circadian rhythm, the kind experienced by flight attendants frequently flying through many different time zones, can lead to cognitive deficits. The World Health Organization now classifies shift-work — any work that falls outside of a traditional 7 a.m. to 6 p.m. schedule — as a possible carcinogen to humans. Thus, it’s probably better that you have a regular sleeping schedule for yourself.

Not sleeping won’t hurt anyone

Lies. We’ve already established that sleep deprivation impacts overall performance, but depending on the job, this can actually affect people in dire ways. For example, medical interns pulling 30-hour shifts, usually without much sleep, are 460% more likely to make diagnostic errors in the intensive care unit and have an 170% increased risk of making a major surgical error. Even worse, one in five medical interns will cause a patient serious harm from a fatigue related error, and one in 20 will kill a patient due to fatigue-related error. Moral of the story? Ask your doctor if they’ve had enough sleep before they operate on you.

Melatonin supplements help you sleep better

Not necessarily. Although the misconception about melatonin pills is grounded in the science of how melatonin works to regulate the circadian rhythm, over-the-counter pills do not actually help you sleep better. Melatonin supplements work as a placebo effect, though they can actually be helpful in cases of jetlag, circadian rhythm dysfunction disorders or for older folks who can’t sleep well.

Human beings have always slept uninterrupted throughout the night

Currently, the “norm” is for human beings to sleep monophasically — we fall asleep once and then don’t wake up until the morning. But there is evidence that hundreds of years ago, human sleep used to be biphasic. Humans would sleep for shorter periods of time at night and nap at some point during the day, completing their work in between. This appears to still be a viable way to gain sleep and productivity.

Snoring is harmless

Actually, loud snoring can be indicative of sleep apnea, the disorder in which your breathing repeatedly starts and stops throughout sleep. People with sleep apnea are at higher risk of heart attacks, asthma, high blood pressure, cancer, cognitive and behavioral disorders and more. They often suffer from chronic fatigue from waking up over and over again. 

So hopefully, you’ve cleared up some of the myths or pseudosciences you might have heard about sleep and picked up some new tricks or tips to improve your rest!