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Sleep Science Simplified: What Part Of The Brain Controls Sleep-Wake Cycles?

The part of the brain that controls your sleep-wake cycle is called the hypothalamus. It has a small group of cells called the suprachiasmatic nuclei (SCN) that act like your body’s internal clock. The SCN help with deciding how much sleep hormone your body should produce.

what part of the brain controls sleep-wake cycle


A small group of cells inside the hypothalamus controls your sleep-wake cycles.

This group of cells helps to produce melatonin, which makes you sleepy at night.

Things like shift work and jet lag can interfere with your body’s sleep-wake cycle. 

Did you know?
Sleep-wake cycles are not only found in humans but also in many other living organisms. Circadian rhythms are present in animals, plants, and even some types of bacteria.

The brain is a fascinating and complex organ. There’s still a long way to go in fully understanding the nuances of its complexities, but what we do know is that the hypothalamus controls our sleep-wake cycles. More specifically, it’s a tiny group of cells inside your hypothalamus called Suprachiasmatic Nuclei (SCN).

SCN react to the light your eyes see, keeping you alert when it's bright and telling your body to produce melatonin when it's dark, so that you start feeling sleepy. In this blog, we explain the sleep-wake cycle and share some tips on maintaining healthy sleep despite factors like shift work, jet lag, or irregular sleeping patterns.

What Is The Sleep-Wake Cycle?

The sleep-wake cycle, also known as our body's natural clock, is a system that helps us know when to be awake and when to sleep. It’s like our internal rhythm, and most people know it as the circadian rhythm.

This rhythm usually follows a 24-hour pattern, but it can be a bit different for each person.

Now, here’s the cool part: Melatonin, which we call the sleep hormone, plays a big role in this cycle. When it's dark in the evening, melatonin levels go up, making us feel sleepy. In the morning, when it's bright, melatonin levels go down, and that's why we wake up.

Light is essential too! Getting sunlight, especially in the morning, helps set our inner clock to wake us up during the day and sleep at night. But, if we use phones and other gadgets with bright screens late at night, it can make it hard to fall asleep, and mess up our entire sleep cycle.

Let’s talk more about what part of the brain controls your body’s sleep cycle.

women sleeping with bearaby cuddler

What Part Of The Brain Controls Sleep-wake Cycles?

The hypothalamus is a region at the base of your brain that helps with regulating the internal balance of your body. Located in the hypothalamus are the suprachiasmatic nuclei (SCN) that ultimately control your circadian rhythms.

But how do they do that? Well, these cells receive information from another group of cells in your eyes about how much light you are exposed to. After that, the SCN either increases or decreases the release of melatonin, so that you either start feeling sleepy or more alert.

When SCN’s usual workings are disrupted – think shift work or jet lag – our ability to fall asleep is thrown off. And when we don’t sleep well, then other parts of the body can fall out of sync too. Now let’s dig a little deeper to see why this is the case.

How Does The Brain Regulate Sleep-Wake Cycles?

Because your brain manages your sleep through a complex system of networks, it’s helpful to look at the different parts of the brain involved in regulating your circadian rhythm and how these parts interact.

Besides the SCN in the hypothalamus, as outlined in the previous section, the thalamus is a part of your brain anatomy that also plays an important role. During the day, the thalamus receives information from your sensory organs like eyes and ears. Based on that, it tells you that you can be awake, but at night, it lets your body know that it is time to sleep.

Another important way the brain regulates sleep-wake cycles is through the hormone melatonin. This is a special “sleepy hormone”. The SCN interact with your pineal gland, to produce more melatonin when it gets dark. That's what makes you feel drowsy and ready for bed. In the next section, we look at how exactly melatonin works.

What Is The Sleep Hormone?

Melatonin is a natural hormone produced by our bodies that some people like to think of as the chemical in the brain that makes you sleep. Simply put, it is the connection point between sleep and neurotransmitters (chemical messengers) in the brain.

Melatonin acts like a bedtime signal to the body. It gets stronger when it's dark outside, making us feel tired and ready to sleep. When it's morning and bright outside, melatonin gets weaker, and we wake up.

Some people use melatonin pills to help them sleep, especially when they have trouble falling asleep. These pills can adjust our body's internal clock, which is like a schedule for when we sleep and wake up. But remember, it's important to follow the instructions from a healthcare expert when using melatonin supplements.

Next, let’s look at the relationship between sleep, circadian rhythms, and your brain.

Circadian Rhythms And The Brain

The biological cycle that regulates our pattern of sleep is also called a circadian rhythm. However, the sleep-wake cycle is just one example of a circadian rhythm. There are other circadian rhythms that control other physical, mental, and even emotional changes that you feel throughout the day!

1. Hormones: Circadian rhythms also control when your body releases hormones. For example, cortisol (the stress hormone) can help you wake up in the morning, while melatonin helps you feel sleepy at night. Your hormones play a big role in making sure that wakefulness and sleepiness happen at the right times.

2. Thinking and Circadian Rhythms: Your brain works better during the day when your rhythms say it's time to be awake. This is when your memory, focus, and problem-solving skills are at their best.

3. Circadian Rhythm Disorders: Some people have trouble matching their inner clocks with the outer world. They might sleep at the wrong times or have trouble staying awake during the day. These are called circadian rhythm disorders.

Understanding how these rhythms work and how they’re connected to your brain is important when looking after your sleep health. If you follow your body's natural rhythms and try to be mindful of things that can mess it up, it becomes easier to maintain better overall well-being.

Let’s see what typically disrupts circadian rhythms.

wrapping up with bearaby grey napper

Factors That Can Disrupt The Sleep Wake Cycle

Many things can make it hard to sleep well and stay awake during the day. Here are some common reasons:

1. Shift Work: Working at non-traditional hours, like night shifts, can unsettle your body's natural sleep routine.

2. Jet Lag: When you fly across many time zones, your body doesn't know what time it is. This can make it hard to sleep and leave you feeling tired.

3. Mixed-Up Sleep Patterns: If you go to bed and wake up at different times on different days, like staying up late on weekends, it confuses your body's sleep cycle.

4. Too Much Light at Night: Staying up late in front of a bright screen or with lights on can stop your body from producing enough of that crucial melatonin.

5. Caffeine and Energy Drinks: Having drinks with caffeine or other stimulants too close to bedtime can keep you awake.

6. Alcohol: Even though alcohol might make some people feel sleepy at first, it can contribute to unsettled sleep during the night.

7. Medications: Some medicines can impact your sleep patterns.

8. Stress and Worry: Feeling stressed or anxious can stop you from falling asleep.

9. Health Problems: Conditions like sleep apnea or chronic pain can make you wake up a lot during the night.

10. Aging: As you get older, your body’s sleep patterns can change, and it’s common to have more trouble sleeping.

11. Napping Too Often: Long naps during the day can make it hard to fall asleep at night.

12. Noisy or Uncomfortable Sleeping: If your sleeping environment isn't comfy or it's noisy, it can be hard to get good rest.

13. Late-Night Snacks: Eating big or spicy meals close to bedtime can cause problems like heartburn and keep you from sleeping well.

14. Menstrual Cycle and Pregnancy: Hormonal changes during a woman’s menstrual cycle or when they’re pregnant can affect sleep too.

So, what can you do to help maintain a regulated and healthy circadian rhythm? We share a few tips below

Tips For Improving The Sleep-Wake Cycle

Improving your sleep-wake cycle can improve your sleep and help you feel better overall. Here are some tips to help you do that:

1. Keep a Regular Schedule: Try to go to bed and wake up at the same time every day, even on weekends. This helps your body get used to a routine.

2. Get Sunlight in the Morning: Spend time in natural light, especially in the morning. It helps your body know when it's time to be awake.

3. Less Screen Time at Night: Don’t use phones, computers, or watch TV with bright screens in the evening. The blue light from screens can stop you from feeling sleepy.

4. Make Your Bedroom Cozy: Your bedroom should be dark, quiet, and just the right temperature for sleep. You can use special curtains and earplugs if it's noisy.

5. Relax to Reduce Stress: Try relaxation exercises like deep breathing, meditation, or yoga to calm down and lower stress that can keep you awake.

6. Watch What You Drink: Avoid caffeine (like in coffee and soda) and alcohol close to bedtime. It's best not to have them a few hours before sleep.

7. Exercise Regularly But Not Too Close To Bedtime: Finish exercising a few hours before bedtime, so you don't get too pumped up right before sleep.

8. Eat Well: Eat a balanced diet, and avoid big, spicy meals late in the evening.

9. Power Naps Are Best When Short: If you need a nap during the day, make it short (20-30 minutes) and do it earlier rather than later in the day.

10. Relax Before Bed: Find a relaxing bedtime routine, which can consist of things like reading, taking a warm bath, or doing relaxation exercises.

11. For Shift Workers: If you work at different hours, try to have a regular sleep schedule, even on days off. Use dark curtains to make your room dark during the day.

12. Be Careful with Sleep Meds: Sleep medicines can help for a little while, but don't rely on them for a long time. Consider talking to a doctor for the best advice.

13. Use Sleep Aids: Sometimes, our bodies need a little coaxing to fall asleep. This is where sleep aids like weighted blankets come in. Our Cotton Napper, for instance, is evenly-weighted to give you Deep Touch Pressure (DTP), which helps increase the production of the sleep hormone. When you sleep with our Cotton Napper, you also get the soft and cozy feel from our 100% organic cotton fabric, which feels like a warm, comforting hug.

It is important to remember that it may take some time to get used to these changes, so it’s best to be patient and gentle with yourself. Making small, steady changes to your daily routine can help you sleep better and feel your best.

If you have tried these tips and you still have trouble sleeping, it is best to see a sleep specialist.

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In this blog, we answered what part of the brain controls the sleep-wake cycle. In simple terms, the part of the brain that controls your sleep-wake cycle is a tiny cluster of cells within the hypothalamus called the Suprachiasmatic Nuclei (SCN). These cells act as your body’s internal clock, helping you know when it’s time to be awake and when it’s time to sleep based on the light and dark signals they receive. They also play an important role in regulating the production of the sleep hormone melatonin.

To keep your sleep-wake cycle in balance, it's essential to consider factors like exposure to natural light, managing screen time, and avoiding habits that disrupt your circadian rhythms. When trying to fall asleep, sleep aids like eye masks or weighted blankets can be useful natural tools.