30 things you should know about sleep - Most of the things we know about sleep have only been discovered in the last 30 years. We continue to research what happens when we sleep, how we dream, and why we dream. Check out the following images and learn more about sleep!

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12% of people dream in black and white - According to a study at the University of Dundee, before color television was invented, only 15% of the population dreamed in color. Now the numbers are the opposite, and older people are much more likely to dream in black and white than younger people.

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Bed time - Humans spend a third of their lives sleeping.

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The longest time without sleep - The longest recorded period without sleep is 11 days. A Californian student named Randy Gardner went this long in 1964. He experienced hallucinations from the sleep deprivation.

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Deaf people and sign language - It's not uncommon for deaf people to use sign language in their dreams. There are several cases of people claiming to have seen their deaf partners use this form of communication while sleeping.

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Can't get up - Don't confuse the inability to get out of bed with laziness. There is actually a medical condition called clinomania that makes it extremely difficult for some people to get out of bed in the morning. Yes, it's hard for many people, but especially so for those who suffer from this condition.

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Parasomnia - Parasomnia is a term used to describe a variety of sleep disorders that cause abnormal behavior while sleeping. People with this condition have committed crimes such as driving while sleeping and even homicide.

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The animal that sleeps the least - The giraffe is among the animals that sleep least. They only go into deep sleep for 5 to 30 minutes per day. They are also able to sleep while standing.

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Herbivores and carnivores - Herbivorous animals sleep less than carnivores because they need to chew for longer periods and be on the lookout for possible predators.

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Sleeping times for humans - The age of a person affects how much they sleep on average. A newborn can sleep up to 17 hours a day, a teenager 11 hours, and an adult 6 to 8 hours.

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Conditions - There are more than 90 conditions directly related to sleep. Some of the most common ones are: insomnia, apnea, and restless leg syndrome.

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Types of insomnia - There are three types of different insomnia: waking up too early and not remembering sleeping at all, difficulty staying asleep, and difficulty getting to sleep.

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Night eating - Getting up in the middle of the night to eat is a fairly common problem but most people don't want to talk openly about it. It's a problem that mainly affects women and can contribute to obesity.

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Sleep deprivation - Sleep deprivation is very harmful to well-being and can lead to memory loss, lack of focus, difficulty in learning, obesity, and cardiovascular stress. The immune system is affected and leaves the sufferer more vulnerable to numerous diseases.

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Dreams - Dreams can range from seconds to an hour. On average, dreams last 10 to 40 minutes.

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World record - Lack of sleep is so dangerous that the record of hours without sleep is no longer in the Guinness Book of Records.

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Smell - Our sense of smell doesn't work while we're sleeping. When someone is subjected to strong odors, they will continue to sleep normally. That is why many people don't wake up when there's a fire, no matter how strong the smell of smoke.

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Sleepless nights - There are habits that can have a serious impact on your sleep. Doing intense exercise at night, drinking caffeine-based drinks, watching TV, and or eating greasy food are not recommended.

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Social media - Several studies indicate that people with the habit of checking social media before bed are more likely to suffer from insomnia and tiredness the following day.

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The sleepiest - Of all species in the world, Koalas sleep the most—up to 22 hours a day.

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Dolphins - Dolphins and whales turn off half of their brain when they sleep. The other half remains active to allow them to breathe.

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Dangers - It takes two weeks without eating for a person to die, but most people would die after approximately 10 days without sleep.

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Falling asleep - On average, a person falls asleep 10 to 15 minutes after going to bed. If this happens, it means that you are tired enough to sleep deeply.

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Babies - According to sonoquality.com.br, having a baby can result in parents losing 400 to 700 hours of sleep. This is one of the most common causes for the development of insomnia during adulthood.

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Sleep paralysis - Have you ever woken up without being able to move? This is sleep paralysis. It happens when the brain awakens during the REM state (the sleep phase where dreams are most vivid), but the body does not.

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Awake for 17 hours - If you stay awake for 17 hours, your cognitive performance will be the equivalent of that of a person with 0.05% alcohol in their blood.

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Women and sleep - According to research, women need an extra hour of sleep than men. Failure to keep up that extra hour may be one of the reasons why women are more susceptible to depression.

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Delaying sleep - The human being is the only mammal that voluntarily delays its own sleep.

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Forgotten dreams - After five minutes of being awake, 50% of what you've dreamed is completely forgotten. After these five minutes, more than 90% of the dream may disappear from your memory. Sigmund Freud believed that dreams are our repressed thoughts and that our brain worked fast to get rid of them. However, this probably happens because the activity of our brain increases greatly when we wake up and we eventually forget the dream.

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More money, more sleep - According to The Sleep Council, people who are better paid tend to sleep better. Cause and effect?

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Fear and nightmares - A study by the University of Montreal found that fear is not the only emotion that causes nightmares. While it also plays a role in them, sadness, guilt, and anxiety are far more conducive to this kind of dream.

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