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Sleep-Wake Cycle:
How Does Your Body Clock Work?
How Does Your Body Clock Work?
Want to sleep better? All you need to do is pay attention to the ticking of your inner clock by recognizing circadian rhythms and keeping the sleep-wake cycle on track. Reading this Habio article can help you learn about healthy sleeping schedules.
The sleep-wake cycle is one of the 24-hour cycles that are part of the body's internal clock. These cycles carry out essential functions and processes. The sleep-wake cycle is, as the name implies, related to sleep patterns (usually around 8 hours at night) and patterns of wakefulness (usually around 16 hours during the day). The purpose of the sleep-wake cycle is to regulate energy and rest. The body's functions that rely on 24-hour cycles are influenced by environmental cues, such as sunlight (or the lack thereof).
What are circadian rhythms?
Circadian rhythms are 24-hour cycles that are responsible for carrying out essential bodily processes and functions. You can think of these cycles as being synchronized by a master clock in the brain. This master clock works by receiving environmental cues, light being the most important one. This is why circadian rhythms are linked with day-night cycles. Circadian rhythms promote consistency and well-being in the body if appropriately aligned.
Stages of sleep
Rapid eye movement (REM) and non-rapid eye movement are the two basic types of sleep. Both of these types are linked with different brain waves and neural activity. During the night, we experience many REM and non-REM sleep cycles. REM sleep gets longer and deeper as the morning approaches.
Stage 1 non-REM sleep: This stage is the transition from wakefulness to sleep, which lasts only several minutes. Bodily processes like heart rate, eye movement, and breathing slow down during this stage of light sleep. The muscles relax, and brain waves get slower than when we're awake.
Stage 2 non-REM sleep: This stage involves light sleep before entering into deeper sleep. Heart rate and breathing slow down further. Muscles become increasingly relaxed, and body temperature drops. Eye movement stops, and brain activity slows down with occasional rises in electrical activity. We spend most of our sleep cycles in this stage.
Stage 3 non-REM sleep: This stage involves deep sleep in which bodily processes get even slower. It is difficult to wake a person up during this stage of sleep. This stage lasts longer during the cycles in the first half of the night.
REM sleep: This stage is characterized by the rapid movement of eyes from side to side. Bodily processes get faster and appear similar to that seen in wakefulness. Most dreaming occurs during this stage. Our limb muscles are temporarily paralyzed in this stage of sleep so that we don't act out our dreams. Older people spend less time in this stage.
Stage 1 non-REM sleep: This stage is the transition from wakefulness to sleep, which lasts only several minutes. Bodily processes like heart rate, eye movement, and breathing slow down during this stage of light sleep. The muscles relax, and brain waves get slower than when we're awake.
Stage 2 non-REM sleep: This stage involves light sleep before entering into deeper sleep. Heart rate and breathing slow down further. Muscles become increasingly relaxed, and body temperature drops. Eye movement stops, and brain activity slows down with occasional rises in electrical activity. We spend most of our sleep cycles in this stage.
Stage 3 non-REM sleep: This stage involves deep sleep in which bodily processes get even slower. It is difficult to wake a person up during this stage of sleep. This stage lasts longer during the cycles in the first half of the night.
REM sleep: This stage is characterized by the rapid movement of eyes from side to side. Bodily processes get faster and appear similar to that seen in wakefulness. Most dreaming occurs during this stage. Our limb muscles are temporarily paralyzed in this stage of sleep so that we don't act out our dreams. Older people spend less time in this stage.
Important circadian rhythm hormones
Many hormones are essential to circadian rhythms. These include melatonin, adenosine, cortisol, and insulin. Cortisol plays a role in wakefulness, while high adenosine and melatonin levels are responsible for feelings of sleepiness. These hormones serve as cues to the biological clock and promote the regulation of bodily functions and processes like the sleep-wake cycle.
Main sleep–wake cycle disturbances
Any disturbance in circadian rhythms can lead to long- or short-term consequences. Let's look at some disorders specifically related to sleep-wake cycle disturbances.
Delayed sleep phase disorder
Some people are night owls and feel most energized at night, but delayed sleep phase disorder is thought to be a more severe condition that negatively impacts daily life. People with delayed sleep phase disorder are unable to go to bed at a reasonable time and get up late in the morning. This disorder is thought to impact 16% of the teen population. The disorder's exact cause is unknown, but some researchers think it could be related to genetics, behavior, or particular physical conditions.
Advanced sleep phase disorder
People with this disorder get tired early in the evening and get up very early in the morning. Roughly 1% of the older and middle-aged population is affected by this disorder. Its cause is thought to be associated with genetics.
Hypersomnia
People with hypersomnia remain excessively sleepy during the day. They experience sleepiness even after getting enough rest at night. There is no single cause of this disorder, and the reasons may include a physical condition, drug abuse, or another sleep disorder.
Insomnia
Insomnia is the opposite of hypersomnia. People who have insomnia find it hard to fall asleep, causing a disturbance in their sleep-wake cycle. Insomnia can be acute or chronic and can have multiple causes including stress, medication, neurological problems, and psychological disorders.
Jet lag
People who take intercontinental flights often suffer from jet lag. Jet lag happens when people cross multiple time zones in a short period of time. These people continue to experience sleep problems and fatigue until their circadian rhythm adapts to their new location's day-night cycle.
Shift work disorder
People who work night shifts often experience significant disturbances in their circadian rhythm because it comes at odds with their day-night hours.
9 ways to reset your circadian rhythm if it has fallen apart
The good news is that we can always work on resetting our circadian rhythm if it has been disturbed. There are numerous tips available, but you need to choose what suits you the most. Let's look at some easy and workable ways of resetting your sleep-wake cycle.
1. Limit screen time in the evening
It is a magical trick to improve your sleep-wake cycle. Using a mobile phone or laptop before bedtime is not good for our sleep quality and quantity. When we use electronic gadgets, the screens expose us to a certain tone of light, limiting melatonin production in our body. This can make us feel alert instead of sleepy. Turning off or dimming the lights before bedtime can help your brain produce more melatonin and make you feel tired.
2. Create a regular sleeping schedule
It is crucial to develop a fixed sleeping schedule. Establish healthy bedtimes and wake-up times, and try to stick to them as best as possible. Try not to deviate from the schedule by staying up late or waking up late. This will help your internal clock develop a healthier routine.
3. Get outside in the daytime
Daylight is an important cue to our bodies to know if it's day or night. Environmental cues influence our circadian rhythms. Exposure to light can help the body adapt to the day–night schedule of the environment. Getting regular exposure to daylight can help develop a regular sleeping schedule.
4. Make it a habit to go to sleep on time
It is imperative to go to bed on time regularly. A good sleeping routine can only be developed and maintained by following it regularly. You can try setting a reminder for your bedtime, just like you would set an alarm to wake up. You can also try rescheduling your daily routine to allow yourself a reasonable amount of time for sleep. Different things work for different people. Choose what fits you the most.
5. Don't nap
Excessive daytime naps can make it difficult for you to get to sleep at night. Avoid taking naps after 3 p.m. to avoid disturbing your sleeping schedule. Read Habio's article on 9 healthy sleep habits to find out more about practical ways to improve sleep.
6. Enhance your bedroom atmosphere
As stated earlier, our sleep-wake cycle is affected by environmental cues. This is true for your bedroom, too. Adjust the light, temperature, and other room components in a way that encourages rest and comfort. Dimming your room light can help your body produce more melatonin, which can increase your feelings of sleepiness.
7. Keep a regular meal schedule
Avoid eating meals late at night. Your circadian rhythm responds to your eating habits as well. Eating early provides your body with more time to digest the food. Additionally, the quality of your food may also impact your sleep.
8. Try meditation
There are a plethora of benefits of meditation when it comes to health. It helps the body feel relaxed. It also reduces stress, and stress can lead to sleep-wake cycle disturbances. Try sleep meditation to get the benefits of meditation with the added bonus of healthy sleep.
9. Limit caffeine and alcohol
Avoid caffeine to improve your circadian rhythm. Caffeine may delay your body clock's timing, making it difficult to sleep at the right time. Limiting your alcohol consumption is also important to develop and maintain a healthy sleeping schedule. Alcohol does produce a relaxing effect, but excessive use is linked with low sleep quality.
Summary
Who wouldn't want to sleep better? It can sometimes seem impossible to build a healthier sleeping routine, but understanding circadian rhythms can help you achieve your goal. Try the tips in this article to help you reset your circadian rhythm if it has been disturbed in order to avoid negative consequences. Some sleep-wake cycle disturbances include jet lag, shift work disorder, hypersomnia, insomnia, delayed sleep phase disorder, and advanced sleep phase disorder. Try any or all of these tips until you find the ones that work for you.
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