Why do you wake up in the middle of the night with a sleeping arm

It is one of the sensations most unpleasant that exist in the world. You wake up in the middle of the night and you notice that your arm has become a cactus, as if thousands of needles will prick your skin and when trying to move your fingers that impression It accentuates. Little by little, your sleeping arm wakes up, and you can hug again Morpheus.

As children, the first times that happens to us we panic, thinking that we will never recover again our precious member. As we become adults we discover that the arm always comes back, although we may worry about the fact if it happens to us often. In general we think it is because we fail the blood flow, But the reality is different.

The nerves

James Dyck, neurology researcher of the Mayo Clinic, says in 'Vox' that it is a very common phenomenon: "It is a good example of how the body tries to protect itself from sleep paralysis." He said that the belief that the numbness or the feeling of pins has to do with lack of blood flow in the nerves it is typical but in reality it is completely wrong. "Most likely due to the nervous understanding The nerves are being pressed and crushed and that causes the symptoms", Explain.

One reason is that during REM sleep the brain sends a signal to cause paralysis. Another, that during that phase you were in bad posture

In the arm we have several nerves, each of them fulfills a function: the axillary Raise your arm by the shoulder the musculocutaneous bend your elbow, the radial straighten your arm and lift your wrist and fingers and the ulnar extend the latter. Dyck explains that the exact physiology is not fully understood, but that the effect that occurs when compressing these nerves during sleep is something like stepping on a hose.

But why does the arm feel paralyzed upon waking up? Dyck suggests two reasons: the first is that he is temporarily paralyzed because during REM sleep the brain has sent a signal to cause paralysis. The purpose of this is to prevent you from acting and ultimately moving while you sleep, but the problem is that if you wake up during this phase you will be aware but you will not have regained control of your limbs, which can cause you true terror. To this state where you are caught between sleep and wakefulness It is known as sleep paralysis, and in ancient times it was known as "ascent of the dead."

If you fall asleep after drinking alcohol in bad posture you could have problems, because your body's ability to wake up and protect you will be less

The second reason it could be because your arm was in a bad position during the REM phase. This way the nerves are compressed, and that can damage them, but the good thing is that the body wakes up when this happens, as protection mechanism. When you open your eyes and try to relieve the pressure, the nerves work again and that's when you experience that unpleasant sensation of pins on your skin, but, contrary to what you might think, it is a good sign. It is a temporary phase that means your nerves are coming back to life.

In general, your nerves are unlikely to be damaged by falling asleep in a bad position. Although Dyck emphasizes that: "If you pass out in a drunken state, you may have more problems, because alcohol impairs your body's ability to wake up and protect you. There is also hereditary neuropathy with risk of pressure paralysis, a genetic condition that makes people more susceptible to injuries from nervous understanding, so these people would have to be more careful and avoid falling asleep in bad postures"But in general, he says, it is a temporary nuisance and you don't have to worry much about it.