Sleep is an important part of your daily routine – you spend about one-third of your time doing it. Quality sleep – and getting enough of it at the right times – is essential to survival as food and water. You can recognize sleep deprivation’s effects on your body and your physical and mental health. Without sleep, you can’t form or maintain the pathways in your brain that let you learn and create new memories, and it’s harder to concentrate and respond quickly.
Why do we need to sleep?
If you have ever felt foggy after a poor night’s sleep, I think you know sleep is necessary.
First, a healthy amount of sleep is vital for “brain plasticity,” or the brain’s ability to adapt to input. If we sleep too little, we become unable to process what we’ve learned during the day, and we have more trouble remembering it in the future.
Scientists have looked at how sleeping affects learning and memory. Each day, at work or school, we learn new things. But the ability to recall and use that information, later on, appears to rely on sleep. In one study, researchers gave two groups of teenagers the same information and told them they’d be tested on it. One group learned that information at 9 a.m. and took the test 12 hours later, at 9 p.m. that same night. The other group learned that information at 9 p.m., had a full night’s rest, and took the test at 9 a.m. the next morning. Even without additional studying time, the students who slept in between did 20% better on tests measuring their material knowledge.
Researchers also believe that sleep may promote the removal of waste products from brain cells, which seems to occur less efficiently when the brain is awake.
“Sleep is the golden chain that ties health and our bodies together. “- Thomas Dekker
Sleep is vital to the rest of the body too. When people don’t get enough sleep, their health risks rise. Symptoms of depression, seizures, high blood pressure, and migraines worsen. Your immune system stops working properly, increasing the likelihood of illness and infection. Sleep also plays a role in metabolism: even one night of missed sleep can create a prediabetic state in an otherwise healthy person.
Phases of human sleep
Human sleep patterns have been categorized into five recurring stages: four non-REM stages and the REM stage. REM and non-REM sleep alternate within one sleep cycle, which lasts about 90 minutes in adult humans.
Waking, a sixth stage often included in the sleep cycles, is the phase in which a person is falling asleep.
The quality of sleep changes with each transition from one sleep stage to another. Each stage is independent of one another, and subtle changes in body functions mark each one.
This stage is referred to as relaxed wakefulness; it is when your body is preparing for sleep. Initially, upon falling asleep, muscles are tense, and eyes move erratically. As you become sleepier, your body slows down, muscles begin to relax, and eye movement decreases.
The first is light sleep, and in this stage, you drift in and out of sleep. Your eyes move slowly, your muscle activity is slow, and you would easily wake up.
This is a light stage of sleep. Your body starts preparing for deep sleep. Eye movements and brain waves slow down, your body temperature drops, and your heart rate slows down. Spontaneous periods of muscle tightening mixed with periods of muscle relaxation are reported.
Stage 3 and 4
These are the deep sleep stages, with stage 4 being more intense than 3. These stages are known as slow-wave or delta sleep. Your breathing, heartbeat, body temperature, and brain waves reach their lowest levels during deep sleep. Your muscles are extremely relaxed, and you are most difficult to rouse.
Stage 5: REM Sleep
Intense dreaming occurs during the REM cycle. Your limbs become temporarily paralyzed during this stage to prevent you from physically acting out your dreams.
“The nicest thing for me is sleep, then at least I can dream.” – Marilyn Monroe
The first REM cycle of the night begins about 90 minutes after you fall asleep and recurs every 90 minutes. Your eyes move around quickly behind your eyelids, and your brainwaves look similar to those of someone awake. Your breathing, heart rate, and blood pressure rise to near-waking levels.
Sleep deprivation and sleep deprivation effects
No animal, including human beings, can survive without sleep.
As far back as 1894, Russian physician and scientist Marie de Manacéine found that when he kept puppies in constant activity with no sleep, they died after only a couple of days. As for us humans, scientists and citizen scientists alike have deprived either themselves or their research participants of sleep for prolonged periods of time, and all noted similar sleep deprivation effects: A decrease in mental functioning, a lack of awareness and attention to the world around them, a distorted sense of time, and immense fatigue.
According to the U.S. Centers for Disease Control and Prevention, more than 80 million American adults suffer from chronic sleep deprivation, meaning they sleep less than the recommended minimum of seven hours a night. Fatigue contributes to more than a million auto accidents each year and a significant number of medical errors. Even small adjustments in sleep can be problematic. The Monday after a daylight saving time change in the U.S., there’s a 24 percent increase in heart attacks, compared with other Mondays, and a jump in fatal car crashes too.
During our lifetimes, about a third of us will suffer from at least one diagnosable sleep disorder. They range from chronic insomnia to sleep apnea to restless leg syndrome to much rarer and stranger conditions.
Sleep is vital for your body.
There is still a lot that we don’t know about the potential benefits of sleep, but one thing is for sure: we can’t survive without it. And the closer we are to getting the optimal amount of sleep, the lesser sleep deprivation effects we will experience, and the healthier we might be.
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