What Happens When You Sleep
If you have a brain, chances are you need to sleep. It is a biological necessity we share with all animals and can change how well we function, respond, act and heal. There is evidence that shows that almost every choice we make during the day can affect sleep: from the food we eat, vitamins, substances we ingest (e.g., caffeine), daily habits, etc.
You probably know that you need sleep but sometimes it’s hard to explain why quality of sleep is so important to focus on.
Sleep plays a huge role in keeping us healthy, and the 5Rs—Refresh, Renew, Restore, Regenerate, and Reconfigure—help explain why. Sleep refreshes your mind and body by clearing out waste and giving your brain a chance to reset. It renews your physical health by helping your muscles heal, boosting your immune system, and recharging your energy. Sleep restores your emotional balance by helping you process memories and manage your mood. During deep sleep, your body regenerates by repairing and growing cells. Finally, sleep reconfigures your brain, making it easier to learn new things and come up with creative ideas.
Understanding the importance of sleep can help us make choices that improve it. There is a reason it’s prescribed by healthcare practitioners and therapists everywhere as one of the backbones to a better life!
The Science Behind Sleep
Sleep may seem like a quiet, inactive state, but it’s actually a busy and dynamic process. During non-rapid eye movement (NREM) sleep, your body slows down its energy use, which helps boost your immune system and repair cells. On the other hand, rapid eye movement (REM) sleep is when your brain works on processing emotions and storing memories. Together, these stages of sleep help you recharge and get ready for the challenges of everyday life.
Sleep patterns in the animal kingdom show just how universal sleep is. Even though sleeping makes animals vulnerable, every species sleeps or has some form of rest. One idea from evolution, called the energy conservation hypothesis, suggests that sleep helps animals save energy by lowering their metabolism and body temperature. You can see this in smaller animals, which have faster metabolisms and need more sleep compared to larger animals.
Hibernation takes this idea even further. Many animals conserve energy during cold months by dramatically slowing down their metabolism.
Recognizing how important and widespread sleep is reminds us to prioritize it in our own lives. Sleep isn’t just a basic need – it’s essential for healing, growth, and thriving in all areas of life.
How Does Sleep Work?
Even though sleep seems like a time when the brain shuts down, it’s actually very active. While you sleep, your brain sorts through the events of the day, deciding which memories to keep and which to let go. The deeper stages of sleep, especially NREM sleep, help lock in facts and skills you’ve learned. REM sleep, on the other hand, focuses on processing emotions and keeping your mood balanced.
Sleep also acts like a cleaning crew for the brain. As you sleep, your brain cells shrink, making space for toxins and harmful proteins to be flushed out through the glymphatic system. This process helps keep your brain healthy and sharp. Meanwhile, your body goes through physical repairs – muscles relax, growth hormones are released, and tissues throughout your body are restored.
Sleep does more than just support your brain — it’s crucial for your whole body, especially your immune system.
While you sleep, your body produces T-cells that help fight infections. Sleep also regulates hormones like leptin and ghrelin, which manage hunger and fullness, making it easier to maintain a healthy weight. Even your skin benefits from sleep, as antioxidants are released to repair damage and reduce inflammation, which is often referred to as “beauty sleep”.
Sleep isn’t just about resting, it’s an active process that keeps so many important functions running smoothly — things we often rely on without even realizing it.
Quantifying sleep: How much is enough?
When it comes to sleep, the question is: How much is enough?
Sleep needs vary depending on age, and getting the right amount helps us function at our best.
Adults generally need 7 to 9 hours of sleep each night.
Older adults (65 and up) might need a little less and often make up for it with naps.
Teenagers, who are still growing and developing, need 8 to 10 hours of sleep. They also naturally tend to stay up later at night and sleep later in the morning.
Sleep is especially important for children as it supports their growth and development.
School-aged children (6 to 12 years old) need 9 to 12 hours of sleep each night.
Toddlers (3 to 5 years old) need between 10 and 13 hours, including naps.
Infants (4 to 12 months old) benefit from 12 to 16 hours of sleep, including nap time.
These sleep guidelines matter because not getting enough rest can affect a child’s cognitive development, emotion regulation, and overall physical health.
What about “just 5 more minutes” of sleep, as we make pleas with our spouse, partner, parent or alarm clock? It may feel harmless, but it can actually disrupt your sleep cycle.
Sleep cycles last about 90 minutes and go through different stages of sleep. When you hit the snooze button, you may begin a new cycle and then wake up before completing it, leaving you feeling groggy and less refreshed.
It’s better to aim for a consistent sleep schedule and avoid interruptions that prevent your body from completing its full cycles.
Sleep Stages
Sleep is divided into two main categories: REM (Rapid Eye Movement) sleep and non-REM sleep. Non-REM sleep itself is divided into three stages: N1, N2, and N3. Each stage is defined by different brain wave patterns and physiological processes.
- N1 (Stage 1) is the lightest stage, the transition from wakefulness to sleep. This phase lasts 1 to 5 minutes and is characterized by relaxed muscles and occasional twitching.
- N2 (Stage 2) represents a deeper level of sleep where your body temperature drops, and your heart rate and breathing become more regular. In this stage, the brain produces bursts of electrical activity, known as sleep spindles, which help resist external disturbances. You’ll spend about half of your night in N2.
- N3 (Stage 3), also known as slow-wave sleep or deep sleep, is the most restorative stage. It plays a key role in repairing tissues, boosting the immune system, and supporting brain functions like memory and creativity.
REM sleep happens in cycles throughout the night and is marked by rapid eye movements and vivid dreams. During this stage, your brain is highly active, while your muscles temporarily become paralyzed to prevent you from acting out your dreams.
Each stage of sleep serves a unique purpose.
Non-REM sleep helps with physical recovery, growth, strengthening the immune system, and storing memories.
REM sleep is crucial for mental tasks like problem-solving, learning, and processing emotions.
Together, these stages work together to ensure that both the body and mind are rejuvenated.
How Can You Tell If Your Sleep is Efficient?
Sleep efficiency refers to the ratio of time spent asleep to the total time spent in bed. Ideally, you want a sleep efficiency of around 85% to 90%. A high sleep efficiency means you are getting the most restorative rest possible.
One way to track sleep efficiency is by using a sleep tracker like a Fitbit. If you don’t have a tracker, you can estimate your sleep efficiency manually by following these steps:
- Note the time you go to bed and the time you wake up.
- Subtract the time it took you to fall asleep (if any).
- Count how many times you woke up during the night and estimate the total time spent awake.
- Calculate the total sleep time and divide it by the total time spent in bed.
For example, if you spend 7 hours in bed but only manage 6.5 hours of sleep due to wakefulness or tossing and turning, your sleep efficiency is about 93%.
The goal is to improve this ratio by minimizing disruptions and ensuring a more restful sleep experience.
Improving sleep quality can involve making simple changes, such as establishing a consistent bedtime, reducing screen time before bed, or engaging in relaxation techniques like meditation or progressive muscle relaxation.
Monitoring your sleep efficiency over time can help you track progress and refine your sleep habits for better health and well-being.
The Theories Behind Sleep
Evolutionary theories suggest that sleep evolved to conserve energy, with NREM sleep lowering metabolism and body temperature. However, studies show that the energy saved during sleep is minimal (equivalent to a stick of celery!) making it unlikely to be the sole reason we sleep.
Interestingly, REM sleep, which shows brain activity similar to when you’re awake, actually uses more energy. This challenges the idea that sleep is just about saving energy.
Key Takeaways
Sleep is more than just rest … It’s a complex and active process essential for keeping your mind and body in top shape. Each stage of sleep plays a unique role in cognitive function, emotional balance, physical recovery, and overall well-being.
From strengthening the immune system and clearing out toxins to helping us manage emotions and lock in new memories, sleep supports nearly every aspect of our health.
Prioritizing quality sleep isn’t a luxury, it’s a fundamental part of living a healthier, more resilient life.
source https://getreconnected.ca/the-science-of-sleep-what-happens-when-you-sleep/
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