Why is Sleep Important? Science-Backed Benefits of Getting Your Zzzzs

Sleep is one of the pillars of high performance.

Your whole body runs better after a good night’s sleep, and considering 80 percent of the population struggles with occasional insomnia,^[1] it’s worth your time to learn how to hack your sleep so you get the most restorative rest possible. The benefits of sleep include better brain function, muscle recovery, hormone balance, longevity, and fat burning.

“I think sleep is honestly one of the greatest biohacks and the biggest performance enhancing thing that you can do,” says sleep expert and Oura Ring creator Harpreet Rai in a recent podcast episode on Bulletproof Radio [iTunes]. “Sleep is the foundation of our health and the foundation of our body and mind.”

Read on to learn the benefits of sleep and how deep sleep upgrades your biology.

Deep sleep improves brain function

Your brain takes the biggest hit when you don’t sleep well. After mild sleep deprivation (staying up for 19 hours), your reaction time, attention, memory, and mental accuracy all drop significantly,^[2] and your brain performs as if you had a blood alcohol concentration of 0.05 percent.^[3] After an all-nighter (24 hours without sleep), you perform like you’re legally drunk.

A night of deep sleep, on the other hand, gives your brain a chance to clear out cellular waste and repair old or damaged brain cells.^[4] You wake up with 50 percent faster mental processing,^[5] stable mood, and an increased ability to learn.^[6]

The key is getting into the two deepest stages of sleep: stage 3, which is when you dream, and stage 4, which is when your brain does the most repair and restoration.

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Low-quality sleep impairs muscle recovery and fat loss

Poor sleep will also slow down your results in the gym. When you don’t sleep well, your hormones go in all the wrong directions: your testosterone and growth hormone levels drop, impairing your protein synthesis so you struggle to build more muscle.^[7] At the same time, your cortisol goes up, promoting fat storage and activating muscle degradation pathways that break down your hard-earned lean mass.^[8]  

If you exercise regularly, aim for between seven and nine hours of high-quality sleep a night. Athletes who got an extra one to two hours of sleep saw significant increases in sprint speed, muscle repair, and hand-eye coordination, as well as decreased fatigue.^[9] They also reported better mood.

Deep sleep helps you live longer and better

Plentiful sleep has a profound effect on longevity, too.

• People who get deep sleep in complete darkness have a 200 percent lower risk of cancer than people who don’t sleep well or sleep with light exposure at night.^[10] Researchers suspect the change in cancer risk has something to do with how consistently you produce melatonin, a sleep hormone that you don’t produce as well when you expose yourself to light at night. Light exposure has a huge impact on sleep quality, which is why blacking out your room tops the list of Bulletproof sleep hacks. Blacking out your room is the simplest and most effective way to improve your sleep, and it seems it can also dramatically decrease your risk of cancer.  
• Getting fewer than six hours of sleep a night doubles your risk of heart attack^[11] and increases diabetes risk by 25 percent.^[12] That said, five or six hours of sleep a night can be plenty if you improve your sleep quality to make those hours count.
• Consistent sleep deprivation (either low quality sleep or fewer than seven hours a night) increases your overall risk of death by about 25 percent.

If you struggle to get 8 hours of sleep every night, here’s some good news: sleep quality is more important than sleep quantity. You can radically improve your sleep quality with a few simple hacks, several of which are free and easy enough that you can start them tonight. Check out the Bulletproof guide to sleep hacking to learn how to get the deepest sleep of your life.