25 Things Your Body Does While You Sleep

As most of our muscles became inactive during sleep, the body burns fewer calories than during the day, so body temperatures drop. Scientists have figured out that your body temperature is usually lowest at around 2:30 am.

Though covered with lids, your eyes move in sleep. In fact, their movement even differs from the particular stages of sleep. First, they roll, and later on, when we get into a deeper sleep, they twitch and dart about. However, we usually don’t remember this.

Sudden twitches and hypnic jerks are mostly associated with the first stages of sleep. They are usually harmless, but they might be strong enough to actually wake you up.

There is a good reason why most of your muscles become paralyzed in sleep – if they were active, you would be able to act out your dreams, which would be, of course, extremely dangerous.

The top layer of the skin is made of closely packed dead cells which are constantly shed during the day. In sleep, the skin’s metabolic rate speeds up, and many of the body’s cells show increased production and reduced breakdown of proteins. As proteins are needed for cell growth and repair of damage from factors like UV rays, deep sleep may indeed be beauty sleep.

“We take in all this information all day long, and most of it is luckily forgotten,” says sleep specialist Christopher Colwell at UCLA School of Medicine. “If you remembered everything, it would fill up your brain, so a sorting process takes place during sleep.”

Unlike most other muscles, throat muscles do not become paralyzed during sleep as they are needed for us to breathe. However, they are more relaxed, causing the throat to narrow. This might also help contribute to snoring.

During slow-wave sleep, the human body secretes bursts of growth hormones that stimulate growth, cell reproduction, and cell regeneration. All sleep, even during the day, is associated with secretion of prolactin, an important regulator of the immune system.

It has been shown that sleep deprivation affects the immune system. One study showed that people who received flu shots and were sleep-deprived the next night did not create the antibodies required to protect against the flu. Therefore, if you notice the first signs of an infection, try to sleep as long as you can to give your immune system time to beat the illness.

While sleeping, you lose water through perspiring and breathing out humid air. This happens during the day too, but eating and drinking negates any weight loss. Therefore, having a good and long sleep is necessary for any diet to be successful.

As saliva is mostly needed for eating, and we don’t eat while sleeping, the salivary flow is reduced in the night. Consequently, you might have dry mouth and be thirsty when you wake up in the morning.

It is estimated that about 5% of people suffer from a bizarre condition known as sleep bruxism. This parafunctional activity manifests itself by excessive teeth grinding and may eventually lead to damage of the teeth. Scientists are not sure what exactly causes this condition, but they believe it might be a form of stress relieving.

It has been discovered that people can be up to several centimeters taller in the morning than they are in the evening. While sleeping in a horizontal position, your spine extends as the weight of your body doesn’t press down on it.

When sleeping, you experience what is known as “nocturnal dipping” of your blood pressure. If you’re otherwise fit, your blood pressure can drop by about 5 to 7 points with a good night’s sleep.

Scientifically known as parasomnias, sleepwalking and other mid-sleep activities include behaviors, emotions, perceptions, and dreams that usually occur during the transitions between some of the sleep stages. Parasomnias are mostly harmless, but there have been cases when people injured themselves while sleepwalking.

Both men and women might get sexually stimulated while sleeping. As your brain is more active during sleep, it requires more oxygen. As a result, blood flow all over the body increases, causing swelling of genitalia.   Interested in more cool sleep-facts? Take a look at our list of 25 Cool Facts About Sleep You Probably Didn’t Know.

The content and purpose of dreams are not fully understood, but it is known that an average person has 3 to 5 dreams per night. Dreams mainly occur in the first stage of sleep when your brain is the most active; however, most dreams are immediately or quickly forgotten.

A recent study has found that the brain can process information and prepare for actions during sleep, effectively making decisions while unconscious. In fact, your brain can even make important connections and discoveries while you are dozing.

You won’t be happy to hear this, but during the night, your anal sphincter muscles loosen slightly, making it easier for the gases in your intestines to go out. The good news is that your (and everyone else’s) sense of smell is reduced while sleeping, so your farts will probably go unnoticed during the night.

Getting rid of toxins allows your body and brain to rejuvenate. In people who don’t sleep well, the filtration isn’t as effective, so experts say that may help explain why people who are sleep-deprived can go a little crazy.

Scientific studies have found that people wake up many times while sleeping, but these awakenings are so brief that we don’t remember them. They usually occur during the transition periods between different sleep stages.

Millions of people all over the world suffer from a sleep disorder known as sleep apnea. The disorder is characterized by pauses in breathing or instances of shallow breathing during sleep. Each pause can last for a few seconds or even several minutes.

Exploding head syndrome is a rare benign condition in which a person hears loud imagined noises (such as a bomb exploding, a gunshot, or a cymbal crash) or experiences an explosive feeling when falling asleep or waking up. It is painless but frightening for the sufferer.

Sleep talking is a parasomnia that refers to talking aloud while asleep. It can be quite loud, ranging from simple mumbling sounds to loud shouts and long, frequently inarticulate speeches. It can occur many times during a sleep cycle.

When your body is totally relaxed to the point of being paralyzed, the nerves can’t receive pain signals and report those signals to the brain. This is also why we don’t hear, smell, see or feel well during sleep.