Our bodies do vital work while we sleep. Yet few of us sleep enough. What’s more, the social connotations surrounding sleep seem to make sleep deprivation matters that much more prevalent. In contradiction to all the available research, many remain convinced that skimping on sleep is something of heroism, when—in fact—it wreaks havoc.

Adults need 7-9 hours of sleep each night to ensure that the body’s productivity, mood, and general health and wellbeing. But in a society where 5 hours of sleep (or less) is glorified—and even promoted—it can be difficult to decipher fact from fiction when it comes to optimal sleep habits.

Below, find some of the most common misconceptions about sleep and what the science actually says.

1. 5-6 hours of sleep is sufficient

A (very) small percentage of people—1%, to be precise—are short sleepers; they truly only need 5-6 hours of sleep per night to maintain good health. Increasingly, though, it appears that over half the population believes—incorrectly—that they belong to this group. The majority of people need 7-9 hours of sleep per night. Don’t think that needing sleep is a sign of weakness or laziness. Sleep makes us better at everything.

2. You can learn to get by on less

You can usually run on empty (or 0-6 hours of sleep) for a day or so. But after a few days, sleep deprivation kicks in and you won’t be able to hide the signs: irritable moods, voracious hunger, decreased productivity, and major metabolic disruption. These side effects will continue until you get the sleep your body needs; there is no way to train the body to reduce its sleep requirement. Lack of sleep entails such disruption to biological performance that enough of it results in death.

3. Alcohol ensures a sweeter slumber

The relaxing nightcap is a myth, regardless of whether it's a glass of red wine, hot buttered rum, or a crisp beer. Sedative effects of alcohol may help you fall asleep faster, but its harmful impact on sleep quality far outweighs any benefit. Not only does alcohol make you more likely to wake up during the night, but it also keeps you from achieving that deep, REM sleep that’s so imperative to everyday function.

4. Lying in bed with your eyes closed is as good as sleeping

Endocrine, cardiovascular, metabolic, and cognitive functions are considerably different during wakefulness versus non-rapid eye movement (REM) sleep. Brain activity during sleep, for example, takes on a very different pattern compared with activity in the awake brain. Sleep and awake regulatory centers in the brain function like an “on-off” switch, in which case you’re either sleeping or you’re not, with little overlap. There’s also a sharp nocturnal “dip” in core body temperature when individuals are asleep compared to when they’re lying awake in bed. Lying awake in bed rests your body on a surface level. But true, restorative therapy only comes with sleep.

5. You need less sleep as you get older

It may seem like older people don’t need as much sleep as other adults. In truth, they need just as much as other adults: 7-9 hours per night. They may, however, have more trouble getting it, due in part to comorbidities or simply the aging process: the older brain is simply unable to generate sleep. A number of independent studies concluded that older adults actually get less sleep than younger adults due to the aging process. But the total need for sleep does not decrease as we age.

6. Naps are good

Naps can provide great health benefits: they can stimulate the immune system, calm the cardiovascular system, and help with memory. But they can prevent a good sleep at night. Adenosine (a sleepiness chemical) builds up in your brain throughout the day. After about 16 hours of accumulation, you should feel tired enough to fall asleep and stay asleep. Then, sleeping at night clears away the chemical entirely, so that you wake up feeling refreshed. Taking a nap that’s too long or too late in the day means you may find it more difficult to fall and stay asleep at night. Bottom line? Find a nap routine—if you need one—that works for you.

7. You can make up for a sleep deficit by sleeping longer the next day

Sleep doesn’t work like a credit system. You can’t accumulate a sleep debt, then pay it off over the weekend. You can’t get back the sleep you lose one night with recovery sleep the next. Your body simply is not capable of regaining lost sleep. Your body expects sleep in each 24-hour period as part of a non-negotiable biological necessity.