Understand Sleep: science, benefits, disorders, and tips.
Did you get enough sleep this past week? Do you remember the last time you woke up feeling refreshed without needing an alarm clock? You’re not alone if you answered “No” to either of those questions. Two-thirds of adults in developed nations don’t get the recommended eight hours of sleep each night.
Sleep is one of the most vital aspects of our health, yet it’s often overlooked in our busy lives. It plays a critical role in maintaining our physical well-being, enhancing memory, and improving mood. The benefits of quality sleep are immeasurable. However, many of us, including you, may struggle with getting enough restful sleep due to hectic schedules, stress, or poor habits.
Let’s dive into the fascinating world of sleep and explore a brief overview together.
The Science of Sleep
What is Sleep?
Sleep is a natural state of rest where you become less aware of your surroundings and respond less to what’s happening around you. It is crucial for life, happens as part of a daily cycle, and includes specific stages of brain activity. Unlike being unconscious, sleep is temporary, can regulate itself, and helps the body recover and recharge.
Sleep is defined on the basis of behavioral and physiological criteria dividing it into two states: rapid eye movement (REM) and non rapid eye movement (NREM) sleep.
Understand it easily, surely you must be watching, some people are in sleep but their eyes move rapidly back and forward. That’s the time the brain is active and they are in a dream. That means most of the dreams occur in this stage. This sleep is called REM (rapid eye movement).
On the other hand, people’s eyes do not move rapidly. This sleep is the quiet, restful phase. where our body repairs itself and grows, this sleep is subdivided into three stages (N1, N2, N3). This sleep is called NREM (non-rapid eye movement).
Muscle tone, brain wave patterns, and eye movements can differentiate each phase and stage of sleep. The body cycles through all stages approximately 4 to 6 times each night, averaging 90 minutes for each cycle. These two types of sleep are very big topics. We will discuss it more.
How Much Sleep Do You Need?
Nowadays, sleeping is a big problem in this modern age. Everyone from young to old faces this problem. Sometimes this sleep problem can also be genetic. There are different research studies on how much sleep a person needs according to his or her age.
Person Age
Sleeping Time
Newborns (Birth - 2 months)
16-18 hours per day
Infants (2-12 months)
14-15 hours per day
Toddlers (1-3 years)
11-13 hours per day
Children (3-9 years)
10-12 hours per day
Adolescents (10-18 years):
9-10 hours per night
Adults (18-64)
6-8 hours per night
65+ years
16-18 hours per night
Newborns (Birth – 2 months):
Key characteristics:
- Newborns sleep and wake up at random times, with no set schedule.
- Newborns sleep about 16-18 hours a day but in short periods of 2.5-4 hours.
- Newborns have three sleep stages: quiet sleep, active sleep, and indeterminate sleep.
- Newborns go straight into REM sleep from being awake, with each sleep cycle lasting only one or two rounds.
- Newborns have irregular sleep patterns because their bodies can’t tell day from night.
Key characteristics:
- Circadian rhythm development means sleeping more at night and staying awake longer during the day.
- Children’s bodies begin producing melatonin and cortisol at this stage, which helps regulate their sleep-wake cycles in a natural daily rhythm.
- sleep changes from mostly REM to more NREM, and their sleep cycles last about 50 minutes.
- As children grow, their sleep needs gradually decrease, with 5-year-olds typically requiring about 11 hours of sleep per night.
- By age 6, children begin to develop individual sleep timing preferences. Some children are early risers and others become night owls.
- Children have longer REM sleep latencies than adolescents, and spend more time on stage (N3).
Adolescents (10-18 years):
Key characteristics:
- Adolescents typically require more sleep than younger children, usually 9–10 hours per night.
- The onset of puberty leads to a decrease in slow-wave sleep and sleep latency. Additionally, there is an increase in stage N2 sleep.
- Daytime sleepiness occurs more frequently during mid-puberty.
- Adults usually go to bed and wake up earlier, with lighter and more interrupted sleep.
- People aged 65 and above sleep an hour earlier at night and wake up 1.5 hours earlier than those aged 20 to 30.
Circadian Rhythm and Sleep
Circadian rhythm is the natural, internal process in your body that regulates biological functions and behaviors in a 24-hour cycle. It is highly influenced by light and darkness, but also by your food intake, your body temperature, social environment, stress, and your physical activity.
It is most commonly associated with regulating your sleep-wake cycle, it also influences a wide range of biological processes like hormone production, body temperature, digestive system, mental alertness, and immune function.
During the day, when light enters your eyes, your brain reduces the production of melatonin, which helps you wake up. At night, your brain signals your pineal gland to produce more melatonin, which helps you feel sleepy. The suprachiasmatic nuclei (SCN) in the brain control your circadian rhythm. The SCN receives signals from your eyes about light levels, which helps it regulate your circadian rhythm. This ensures that you feel sleepy at night and awake during the day.
Sleep and the Brain
Sleep is essential for maintaining a healthy brain. During sleep, your brain works hard to store memories, repair itself, and remove harmful waste like amyloid proteins, which are linked to Alzheimer’s disease. Insufficient quality sleep disrupts these essential processes, increasing the risk of memory problems, cognitive decline, and other serious brain conditions.
Research shows that sleep disorders like obstructive sleep apnea (OSA) and insomnia significantly impact brain health. OSA, for instance, reduces oxygen supply to the brain, leading to inflammation and damage. Additionally, both insufficient sleep (less than 7 hours) and excessive sleep (more than 9 hours) are associated with an increased risk of stroke and dementia.
Understanding the connection between sleep and brain health helps you make better decisions for your overall well-being. By improving sleep habits and addressing disorders like insomnia or obstructive sleep apnea, you can take meaningful steps toward enhancing brain function and maintaining overall health.
The brain also controls processes like sleep cycles, hormone release, and the transitions between sleep stages. Several key areas of the brain work together to regulate sleep:
- Hypothalamus
- Brainstem
- Suprachiasmatic nucleus (SCN)
- Thalamus
- Pineal gland
- Basal forebrain
- Midbrain
- Amygdala
Asadullah Galib
I am studying for a bachelor of pharmacy degree, but I am also passionate about technology. This passion has helped me develop strong SEO skills, which help businesses grow organically. This combination helps me support the growth of health-focused businesses.
