Why We Sleep

Today, we’re diving into a topic that touches every aspect of our lives but is often overlooked—sleep. In Matthew Walker’s revolutionary book, Why We Sleep: The New Science of Sleep and Dreams, the neuroscientist and sleep expert uncovers how sleep is critical to our physical and mental well-being. Whether you're someone struggling to get enough rest, or simply curious about the science behind sleep, we have 5 key takeaways and actionable tips to help you harness the power of a good night’s sleep.

Sleep is one of the most fundamental biological processes, affecting everything from memory, immune function, and emotional stability, to even life expectancy. In Why We Sleep, Walker explores decades of research that demonstrates how sleep shapes nearly every function of our body and mind. He argues that sleep is as essential to our survival as food and water, yet modern society tends to ignore its importance. Walker’s findings are both eye-opening and sobering, pointing to the critical role that adequate, good-quality sleep plays in living a long, healthy, and fulfilling life.

✏️ 1. The Science of Sleep Cycles

Walker explains that our sleep is structured into 90-minute cycles, alternating between non-REM and REM sleep. Each of these phases plays a unique role in the restoration process: non-REM sleep helps with physical recovery, while REM sleep is essential for cognitive functions like memory consolidation and emotional processing.

💪🏻 Actionable Tip: Try to sleep in multiples of 90 minutes. If you need to wake up at a certain time, calculate your bedtime so that you complete full sleep cycles. For example, if you have to wake up at 7 AM, aim for 9 hours of sleep (6 cycles) by going to bed at 10 PM. This ensures you wake up at the end of a cycle, feeling more refreshed and alert.

✏️ 2. Sleep Deprivation Is a Silent Epidemic

One of Walker’s most startling insights is the global sleep deprivation crisis. Studies show that most people need between 7 and 9 hours of sleep per night, but many of us are getting far less. Chronic sleep deprivation doesn’t just make us tired—it leads to a higher risk of heart disease, stroke, diabetes, obesity, and even dementia. Walker explains that even one night of poor sleep can impair your cognitive performance, while sustained lack of sleep has serious long-term consequences on both physical and mental health.

💪🏻 Actionable Tip: Prioritise sleep as a non-negotiable. Aim for a consistent sleep schedule, even on weekends. If you’ve been skimping on sleep during the week, it’s tempting to ‘catch up’ on the weekend, but this irregularity can actually disrupt your circadian rhythm. Stick to a regular sleep and wake time to support better sleep quality and overall health.

✏️ 3. Sleep and Learning—They Go Hand in Hand

If you're looking to boost your learning and memory, sleep is your best ally. Walker reveals that sleep before learning primes your brain, improving your ability to absorb new information. Sleep after learning consolidates what you’ve taken in, helping you retain it more effectively. The REM phase of sleep is particularly important for creativity, as it helps us make new connections between ideas.

💪🏻 Actionable Tip: Time your study or work sessions with sleep in mind. If you need to learn something new or come up with creative ideas, ensure you get a good night’s sleep both before and after. Avoid pulling all-nighters—while they might give you more time to cram, they drastically reduce your ability to remember what you've learned.

✏️ 4. The Role of Sleep in Emotional Health

Sleep isn’t just a passive process—it plays an active role in managing our emotions. When we don’t get enough sleep, we become more prone to anxiety, stress, and mood swings. Walker describes sleep as "overnight therapy" that helps us process emotional experiences and maintain psychological balance. REM sleep, in particular, helps to ‘smooth the edges’ of painful memories, making it easier to cope with difficult emotions.

💪🏻 Actionable Tip: If you’re going through a stressful time or facing emotional challenges, prioritise your sleep even more. If stress is keeping you up, try relaxation techniques like deep breathing or progressive muscle relaxation before bed. A regular wind-down routine—such as turning off screens 30 minutes before sleep—can also signal to your brain that it’s time to rest and recover emotionally.

✏️ 5. Sleep and Physical Health Are Inextricably Linked

Walker devotes a significant portion of his book to discussing how sleep influences physical health. Sleep is crucial for immune function, hormone regulation, and cellular repair. He highlights studies showing that even a small reduction in sleep can make us more vulnerable to illness. In fact, Walker points out that sleeping less than six hours a night increases your likelihood of catching a cold by four times. Over time, chronic sleep deprivation has been linked to higher rates of cancer, diabetes, and cardiovascular disease.

💪🏻 Actionable Tip: Create a sleep-conducive environment. Temperature plays a key role in regulating sleep; Walker suggests keeping your bedroom cool, ideally between 15-20°C. Also, invest in blackout curtains or a sleep mask to block out light, and minimise noise with earplugs or a white noise machine if necessary. Your body needs the right environment to maximise sleep’s physical health benefits.

Want to learn more? If you would like to buy a copy of Why We Sleep and support us at the same time, you can shop at our affiliate link here. When you buy through this link, we will receive a small commission at no additional cost to you. We’re excited to share our takeaways and insights from the top non-fiction books each week and truly enjoy writing this newsletter. Thank you for your support and for being part of our growing community. 📚️ 

Matthew Walker’s Why We Sleep is a powerful reminder of how crucial sleep is for every aspect of our well-being. In a world that glorifies busyness and sleep deprivation, Walker urges us to rethink our relationship with sleep. By taking sleep seriously and implementing small but meaningful changes, we can improve our mental sharpness, emotional resilience, and overall health.

The key is not to view sleep as an optional extra, but as a core pillar of your daily routine. With the right sleep habits in place, you’ll wake up each day better equipped to handle whatever challenges life throws your way.

I hope this summary has been a powerful reminder that sufficient sleep is a necessity and NOT a luxury. We love to hear from you so feel free to drop us a dm on Instagram with your insights and let us know one thing you’re going to do tonight to help get a better sleep. 😴 

Until next time, stay thriving!

Beck
Team Thrive in Five