8 Surprising Things You Might Be Doing While Asleep


As important as sleep is, scientists don't fully understand exactly how it works or why we have to do so much of it (one-third of our lives is spent sleeping!). It's likely there's a lot going on at night that you don't even know about since sleep is actually quite a busy time for your body. Here are eight things you might be doing without knowing it. 


You might be asleep but your hypothalamus is not. It's carefully keeping time for you as part of your circadian rhythm. This not only helps you feel tired so that you go to sleep with the release of melatonin, but a protein called PER is released in the morning that gradually wakes you up, often right before your alarm clock is set to go off.


What do you have to say when you're asleep? Sleep-talking or somniloquy can range from random noises to complete sentences. About 5 percent of adults do it (it's slightly more common in children), and it can happen during any stage of sleep. It's most common in men and kids, and can be brought on by fever, sleep deprivation, stress, anxiety, or depression. Don't worry though—there's no evidence people tell their deepest, darkest secrets while asleep. The biggest concern may be that you're keeping your sleep partner awake.


Most people grind their teeth while they are asleep, at least sometimes. This habit, called bruxism, can be caused by emotional or psychological states like stress or anxiety, from an abnormal bite (misalignment of your teeth), or even from sleep apnea. Most people are unaware they do this until their dentist notices evidence of unusual wear. If you're damaging your teeth at night, your dentist can give you a mouth guard to prevent it.


You might be having more fun than you realize while you are asleep. A small number of people—about 8 percent, according to one Canadian study—suffer from sexsomnia, which is basically the sex version of sleepwalking. Sexsomnia can not only cause you to have sex with someone without consciously realizing it (and you'll only know if they tell you about it when you're awake), but it can also cause masturbation while sleeping. Men are more likely to experience this than women. Stress, medications, alcohol, and sleep deprivation are risk factors.


Every calorie counts, even those you eat while asleep. Some people experience sleep eating, where they sleepwalk and eat and drink without waking up. People who do this tend to do it once a night, and they eat things that are high-calorie or high in fat and are items they might not normally eat. It can actually be dangerous if you eat non-food items, eat or drink excessive amounts, or injure yourself while cooking. 


You think you're resting, but your brain is doing some serious housekeeping every single night. While you are asleep your brain clears out some memories and cements and reorganizes others. The brain also physically cleans itself with a flood of cerebrospinal fluid, which removes unnecessary proteins that can act as toxins.


Your muscles are frozen for part of every night. It's actually normal and healthy to be paralyzed during sleep. During rapid eye movement (REM) sleep your brain is busy dreaming, but to protect yourself from responding to the dreams (for example, screaming when something scary happens or waving your arms to push away an oncoming danger in your dream), your body's muscles are paralyzed. It's possible to actually wake up during the tail end of this cycle and be awake but unable to move, which can be upsetting or even terrifying. It's also relatively common, having occurred to about 40 percent of people. These episodes usually pass quickly.


You might be conked out at night, but it turns out your body is still working hard. Each night you lose about a pound due to the water vapor you expel while breathing. You also lose weight since you're expelling carbon atoms with each exhalation. Because of this, the best number on your scale will be first thing in the morning, so take advantage of it!

Here's What Actually Happens When You're Electrocuted

Benjamin Franklin was a genius, but not so smart when it came to safely handling electricity, according to legend. As SciShow explains in its latest video, varying degrees of electric current passing through the body can result in burns, seizures, cessation of breathing, and even a stopped heart. Our skin is pretty good at resisting electric current, but its protective properties are diminished when it gets wet—so if Franklin actually conducted his famous kite-and-key experiment in the pouring rain, he was essentially flirting with death.

That's right, death: Had Franklin actually been electrocuted, he wouldn't have had only sparks radiating from his body and fried hair. The difference between experiencing an electric shock and an electrocution depends on the amount of current involved, the voltage (the difference in the electrical potential that's driving the current), and your body's resistance to the current. Once the line is crossed, the fallout isn't pretty, which you can thankfully learn about secondhand by watching the video below.

Big Questions
Does Einstein's Theory of Relativity Imply That Interstellar Space Travel is Impossible?

Does Einstein's theory of relativity imply that interstellar space travel is impossible?

Paul Mainwood:

The opposite. It makes interstellar travel possible—or at least possible within human lifetimes.

The reason is acceleration. Humans are fairly puny creatures, and we can’t stand much acceleration. Impose much more than 1 g of acceleration onto a human for an extended period of time, and we will experience all kinds of health problems. (Impose much more than 10 g and these health problems will include immediate unconsciousness and a rapid death.)

To travel anywhere significant, we need to accelerate up to your travel speed, and then decelerate again at the other end. If we’re limited to, say, 1.5 g for extended periods, then in a non-relativistic, Newtonian world, this gives us a major problem: Everyone’s going to die before we get there. The only way of getting the time down is to apply stronger accelerations, so we need to send robots, or at least something much tougher than we delicate bags of mostly water.

But relativity helps a lot. As soon as we get anywhere near the speed of light, then the local time on the spaceship dilates, and we can get to places in much less (spaceship) time than it would take in a Newtonian universe. (Or, looking at it from the point of view of someone on the spaceship: they will see the distances contract as they accelerate up to near light-speed—the effect is the same, they will get there quicker.)

Here’s a quick table I knocked together on the assumption that we can’t accelerate any faster than 1.5 g. We accelerate up at that rate for half the journey, and then decelerate at the same rate in the second half to stop just beside wherever we are visiting.

You can see that to get to destinations much beyond 50 light years away, we are receiving massive advantages from relativity. And beyond 1000 light years, it’s only thanks to relativistic effects that we’re getting there within a human lifetime.

Indeed, if we continue the table, we’ll find that we can get across the entire visible universe (47 billion light-years or so) within a human lifetime (28 years or so) by exploiting relativistic effects.

So, by using relativity, it seems we can get anywhere we like!

Well ... not quite.

Two problems.

First, the effect is only available to the travelers. The Earth times will be much much longer. (Rough rule to obtain the Earth-time for a return journey [is to] double the number of light years in the table and add 0.25 to get the time in years). So if they return, they will find many thousand years have elapsed on earth: their families will live and die without them. So, even we did send explorers, we on Earth would never find out what they had discovered. Though perhaps for some explorers, even this would be a positive: “Take a trip to Betelgeuse! For only an 18 year round-trip, you get an interstellar adventure and a bonus: time-travel to 1300 years in the Earth’s future!”

Second, a more immediate and practical problem: The amount of energy it takes to accelerate something up to the relativistic speeds we are using here is—quite literally—astronomical. Taking the journey to the Crab Nebula as an example, we’d need to provide about 7 x 1020 J of kinetic energy per kilogram of spaceship to get up to the top speed we’re using.

That is a lot. But it’s available: the Sun puts out 3X1026 W, so in theory, you’d only need a few seconds of Solar output (plus a Dyson Sphere) to collect enough energy to get a reasonably sized ship up to that speed. This also assumes you can transfer this energy to the ship without increasing its mass: e.g., via a laser anchored to a large planet or star; if our ship needs to carry its chemical or matter/anti-matter fuel and accelerate that too, then you run into the “tyranny of the rocket equation” and we’re lost. Many orders of magnitude more fuel will be needed.

But I’m just going to airily treat all that as an engineering issue (albeit one far beyond anything we can attack with currently imaginable technology). Assuming we can get our spaceships up to those speeds, we can see how relativity helps interstellar travel. Counter-intuitive, but true.

This post originally appeared on Quora. Click here to view.