Why can't we hear when we sleep?

Although the ears continue to work normally, the brain then acts as a filtering device and decides whether we respond to that sound and wake up or sleep again.

If we wake up then we can remember hearing the sound, but if we do not wake up, we will never hear it.

This is a special tool because it protects sleep so that we are not awakened by whatever happens around us during sleep.

But that does not mean that the body is completely 'closed' to the outside world, because it is very dangerous.

The brain decides to wake you up or let you sleep again when sounds are heard around you.

The brain responds to loud noises

Loud noises are more likely to wake us up than small noises. For example, the sound of someone dropping a hard object on the floor during the night can startle and wake us up, but we still sleep without knowing the sound of mosquitoes buzzing around us.

An alarm bell that sounds loud makes you wake up more than a whisper right in your ear.

Awakening or not depends on the type of noise anymore

Unusual or important sounds can easily wake us up.

The brain identifies abnormal sounds as a threat and warns us of that danger. This helps us to decide whether we need to defend or to run away when it is deemed necessary.

Just imagine how important and protective it is to our ancestors when they were sleeping in the wild, when there were no houses now, surrounded by many species. predators like tigers, threats from lions.

Luckily today we no longer have to worry as much as our ancestors did, but that defense mechanism is still useful when there are loud or strange noises while we're sleeping, so we have know if something needs to be done or not.

The brain also has the ability to wake up the body when there are sounds that it thinks are important , such as our name. We are more likely to be awakened when someone calls our name than another's.

You are more likely to wake up if your brain thinks that sound is important, such as someone calling your name.

What about deep sleep?

Our sleep consists of shallow sleep cycles followed by deep sleep. Each night, we experience about 5 to 6 such sleep cycles, depending on how long the sleep duration is.

When we are in the deep sleep phase, we are more likely to wake up when we sleep deeply. Usually, we sleep deeper in the first half of the night and sleep deeper in the second half. So we can immediately wake up by the crowing of the rooster when it's just dawn, and before that we still fall asleep because the brain skipped that crunch just before we were sleeping. deep.

Everyone's body is different

Each person has different sensitivity level to the sound.

The conversation of everyone in the house while you are sleeping may not wake you up if you are not sensitive to noise. But for people who are very sensitive to noise, they will find it very uncomfortable and unable to sleep when people are chatting around.

If you are sensitive to sound, your brain is also very easy to make a decision to wake you up.