You can still hear when you sleep, but your brain acts as a filter, significantly reducing your awareness of sounds, especially during deep sleep, to allow for rest; it prioritizes important noises like alarms or cries but tunes out background sounds like a fridge hum, a process that helps protect you while you're vulnerable. This filtering becomes more intense in deeper sleep stages (slow-wave/REM), making you less likely to wake unless a sound is crucial or very loud.
Deep sleep – During deep sleep, or slow-wave sleep, the brain disconnects from the outside world. You are less likely to hear external sounds or be disturbed by noises in the environment. During this sleep stage your brain consolidates memories from the day, and stores memories in long term memory.
Can You Hear While You're Sleeping? The study concluded that people do hear while they're sleeping! And we even process the sound we hear, and decide which sounds to pay attention to. This happens the most during Stage 1 and Stage 2.
The 3-2-1 sleep rule is a simple wind-down routine: stop eating and drinking alcohol 3 hours before bed, stop working/mentally stimulating activities 2 hours before, and turn off screens (phones, TVs) 1 hour before sleep, helping you transition to rest by reducing stimulants and preparing your mind and body. It's often part of a larger 10-3-2-1-0 rule, which also adds no caffeine 10 hours prior and no hitting snooze (0) in the morning.
During light sleep stages, such as stage 1 and stage 2, we can still process and respond to sounds in our environment. While our auditory system remains active during sleep, the threshold for sound perception increases as we enter deeper sleep stages, such as slow-wave sleep (SWS) and rapid eye movement (REM) sleep.
These common behaviors and signs of sexsomnia include:
While everyone occasionally sleeps in, chronic oversleeping — needing 10, 11 or more hours regularly — can be linked to underlying health issues. “Conditions like thyroid disorders, anemia or sleep apnea can all lead to excessive fatigue and longer sleep durations,” says Dr. Namon.
The koala is the animal that sleeps approximately 90% of the day (20-22 hours), a necessity due to its low-energy eucalyptus diet requiring intensive digestion, making it the ultimate champion of sleep in the animal kingdom, followed closely by sloths and bats.
Gen Z stays up late due to a combination of technology (blue light, endless content), significant stress and anxiety (FOMO, financial/global worries), biological shifts (natural teenage circadian rhythm), and "revenge bedtime procrastination," where they sacrifice sleep for personal time, often in bed, scrolling social media. This digital-heavy, high-stress lifestyle creates overstimulation and a misalignment with natural sleep patterns, leading to chronic sleep deprivation, notes the American Academy of Sleep Medicine and the Sleep Health Foundation.
Talking in your sleep is a kind of parasomnia, or a disruptive sleep-related disorder that happens while you're sleeping. Unlike other parasomnias like sleepwalking or sleep-related eating disorder that can carry significant risks to your health and well-being, sleep talking usually has little to no risk.
People may be confused or disoriented if you wake them while they're sleepwalking. In rare instances, they might respond out of fear or anger to whatever — or whomever — woke them up. If you have to wake a sleepwalker, do it gently and try not to scare or startle them.
The Brain Takes Over
What changes during sleep isn't our ears' ability to detect sound, but how our brain processes it. As we move through different sleep stages, especially deep sleep, our brain becomes less responsive to external sounds.
However, there are still some common signs that should prompt you to get checked and seek treatment for sleep apnea:
Sleep paralysis is scary because you're conscious but temporarily unable to move or speak, combined with vivid, terrifying hallucinations (like shadowy figures or intruders), intense pressure on the chest (feeling of suffocation), and overwhelming panic, making you feel trapped in a living nightmare that feels real. These frightening sensory experiences occur because your brain is partly awake during REM sleep (when muscles are naturally paralyzed) and dream elements bleed into your waking perception, often interpreted as supernatural threats.
The answer is “probably.” Research has shown that many animals experience a sleep phase similar to humans known as REM (Rapid Eye Movement) sleep, which is closely associated with dreaming. This phase is characterized by increased brain activity and is when most vivid dreams occur.
The longest time a human being has gone without sleep is 11 days and 25 minutes. The world record was set by American 17-year-old Randy Gardner in 1963. When the experiment ended, Gardner had been awake for 264 hours and 25 minutes.
🐌 Did You Know this amazing animal fact? A snail can sleep for up to 3 years! Yes, some snails can hibernate or go into deep sleep to survive harsh weather.
Own Your 3-Foot Space In Navy SEAL training, there's a simple but profound principle: Own your 3-foot space. It means focusing on what's directly within your control—your actions, your attitude, your effort—no matter how chaotic the environment around you becomes.
A prime example is the box breathing technique, famously used by the Navy Seals, known as the 4-4-4-4 method. This simple yet effective method involves a cycle of inhaling for 4 seconds, holding the breath for 4 seconds, exhaling for 4 seconds, and then pausing for 4 seconds before the next inhalation.
10 hours before bed: No more caffeine. 3 hours before bed: No more food or alcohol. 2 hours before bed: No more work. 1 hour before bed: No more screen time (shut off all phones, TVs and computers).
On average, Japanese sleep about 7 hours and 20 minutes a night, - the least among 33 OECD member countries. And the number of insomniacs is growing. But even as more people suffer from insomnia, help can be hard to find.
Signs of poor core sleep (deep, restorative sleep) include waking up foggy, daytime fatigue/energy crashes, poor concentration, irritability, frequent illness, memory issues, and mood swings, indicating your brain and body aren't fully repairing and consolidating memories. You might also experience increased sugar cravings, slow muscle recovery, and a weakened immune system.
Musk goes to bed around 3 a.m. and gets about 6 hours of sleep every night. Although he's not getting eight hours a night, Musk has upped his sleeping schedule from being nearly nonexistent in the past. In May 2023, Musk told CNBC that he's no longer pulling all-nighters.