Sleep is a state of altered consciousness in which we become less aware of what’s going on around us. Sleep can take different forms in different animals. Dolphins, for example, sleep just half a brain at a time, and can even continue to swim while asleep.
For humans, sleep involves four stages, called N1, N2, N3 and rapid eye movement (REM). N1 is the lightest stage of sleep. It usually occurs right after you fall asleep, and typically lasts less than 10 minutes. During N2, you sink deeper into sleep. This stage is characterised by brief, high-amplitude brainwaves called ‘K-complexes’ and bursts of lower amplitude waves called ‘sleep spindles’. The N3 stage is the deepest stage of sleep, and is characterised by slow brain waves called delta waves. Finally, during REM sleep your brain activity and breathing rate speed up, and your eyes move quickly in lots of directions. Our most vivid dreams tend to occur in REM sleep, and our brain paralyses our muscles so that we’re unable to act them out. During the night, we continually cycle through these four sleep stages, with a full cycle taking around 90 minutes in adults.
HOW MUCH SLEEP DO WE ACTUALLY NEED?
Bu hikaye BBC Focus - Science & Technology dergisinin October 2020 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
Already a subscriber ? Giriş Yap
Bu hikaye BBC Focus - Science & Technology dergisinin October 2020 sayısından alınmıştır.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
Already a subscriber? Giriş Yap
5 SIMPLE WAYS TO RECLAIM YOUR ATTENTION
Primed for constant interruptions, your brain is now distracting itself, says science. It's time to break the cycle and retrain your focus
GOING ROGUE
Some planets are stuck following the same orbital paths their entire lives. Others break free to wander alone through the vast, empty darkness of interstellar space and there's a lot more of them than you might think
BED BUGS VS THE WORLD
When bloodthirsty bed bugs made headlines for infesting Paris Fashion Week in 2023, it shone a spotlight on a problem that's been making experts itch for decades: the arms race going on between bed bugs and humans. Now, with the 2024 Summer Olympics fast approaching, the stakes are higher than ever
THE EYES THAT WATCH THE SKY
When it launches in 2026, the Copernicus programme's Anthropogenic Carbon Dioxide Monitoring satellite will give us a new window on to Earth's atmosphere... And how we're altering it
TIME-RESTRICTED EATING LINKED TO HIGHER RISK OF CARDIOVASCULAR DEATH
Skipping breakfast might not be so good for your health, after all
INSIDE THE PROJECT TO SCAN THOUSANDS OF RARE SPECIMENS
A major collaborative project has created 3D reconstructions of previously locked away museum specimens
VIDEO IS FIRST EVIDENCE OF AN ORCA KILLING A GREAT WHITE
Tourists sailing off the South African coast film a never-before-seen event: a lone orca attacking a 2.5m shark
AI REVEALS PROSTATE CANCER IS NOT JUST ONE DISEASE
DNA analysis carried out by artificial intelligence has helped scientists make a discovery that could revolutionise future treatment
MYSTERIOUS WAVES DETECTED IN JUPITER'S CORE
Scientists hope unusual fluctuations in the gas giant's magnetic field might reveal what's inside
MINI ORGANS GROWN FROM UNBORN BABIES MARK A BREAKTHROUGH IN PRENATAL MEDICINE
A new technique could allow congenital conditions to be diagnosed and treated before birth