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Can You Hear While Sleeping?

It has been a long day and you are ready to go to sleep. Most of us think that when we go to sleep, we are unconscious of the world around us. However, depending on the stage of sleep we are in, we may be more aware of what is going on around us than we may suspect. Sleep is a fascinating and mystifying world, where we dream and drift out of this world and into others. This is what is actually what is happening to our hearing while we sleep.

Sleep Stages

Sleeping is a journey, which is classified by different sleep stages. Sleep stages are important because they allow the brain and body to recuperate and develop.

Four sleep stages ideally cycle each night, several times. In fact, on an ideal night, you will have around four to six sleep cycles. Failure to obtain all stages of sleep can cause many of the dangerous consequences of insomnia such as cognitive, emotional, and physical impacts.

  • Stage 1: This is the stage where you enter sleep. You are starting to relax as you transition into rest and you are easy to stir awake in this stage.
  • Stage 2: As you enter the second stage of sleep your heart rate, breathing, and temperature begin to drop. Your brain waves slow, and it is less likely that outside factors will wake you.
  • Stage 3: This is the stage of deep sleep. Breathing and heart rate continue to slow. This stage is essential for regeneration, boosting your immune system health, and healing. This is also when your brain consolidates memories.
  • Stage 4:  REM sleep occurs during Stage 4 and while your body rests, your brain becomes incredibly active. Your brain is almost as active as when you’re awake. This part of sleep is when you have vivid dreams and is important for cognitive functions, learning, and creativity. 

Past Ideas Around Sleep

In the past it was believed that when you fell asleep you were not aware of the world around you, however, these views on sleeping have since been revised. Have you ever been dreaming only to have the alarm clock infiltrate your dream? Has a loud burst of thunder ever woken you out of sleep? Many parents will find that no matter how tired they are they will still wake to the sound of their child crying in the other room. Depending on the stage of sleep you are in you can hear the outside world.

Hearing and Sleep

2019 study in the Human Nature Behavior Journal examined how the brain interacts with the outside world while sleeping. The study determined that the brain is still processing sound around us as we sleep and that the brain noticed some sounds over others.

The study mimicked a party where there were many conversations and sounds happening at once. When you are listening in a crowded room, the brain has to prioritize the conversation you want to hear over others. Have you ever been in the middle of a conversation, only to home in on an adjacent conversation that has a topic which concerns you? This is your brain prioritizing some sounds and topics over others. 

During this sleep study, researchers focused on just two voices: one voice which was saying sentences and phrases, while the other voice was speaking unintelligible gibberish. While the participants started to fall asleep, both these sounds were simultaneously played on headphones. They monitored brain activity using EEG, and the researchers observed more brain activity directed towards the language they understood, over the gibberish.

Hearing in Your Sleep

The study found that you can hear when sleeping particularly during most during Stage 1 and Stage 2. We are only beginning to understand all the amazing things our brains can do, but what we do know is that hearing is important to the quality of our cognitive functioning. Hearing helps us stay connected to the world around us when we sleep and when we are awake. If you have a hearing loss, it is important to have it addressed as soon as possible. Healthy hearing ensures a healthy and nimble brain to connect you to the amazing world around you, 24/7. Schedule a hearing test today, to find out how well you hear.