The combination of mild neuroses and an interest in health led me down the road of “biohacking”, an attempt to hack my brain and body to optimize performance, outside the realm of traditional medicine. After spending much of the last decade experimenting with mental and physical biohacks, like nootropics, diets & fasting, supplements and more, I’ve come to realize biohacking is a fools errand without high quality sleep. Sleep is the ultimate hidden lever. Sleep is essentially our life support system, impacting all areas of the human condition, from mental health and physical activity, to nutrition and general wellbeing.
I’m going to be writing a multi-part series on Sleep because:
- The science of sleep is really cool. Recent discoveries are game-changing, and reveal how important sleep is to overall health.
- How and why we sleep is completely misunderstood by the public.
- As technology progresses, sleep quality is falling by the waist-side, poor sleep is becoming a global epidemic, and believed by many to be the root cause of rising mental health disorders.
I’m going to try and distill hundreds of pages of sleep research into a few major takeaways.
Let’s start with the amount of sleep; the number of hours is mostly a vanity metric. The real reason we’re told to sleep 7-9 hours is because this window gives you the best chance of getting adequate Deep sleep and Rapid Eye Movement (REM) sleep.
The key function of Deep sleep, which predominantly occurs early in the night, is to do the work of cleaning the brain of toxic waste. In contrast, the dreaming stage of REM sleep, which prevails later in the night, plays a role in forging new connections in the brain and is essential for memory and creativity. In other words, Deep sleep performs the role of the “excavator” while REM sleep performs the role of the “builder”.
Sleep kind of works like a ninety-minute seesaw rotating between these two stages. In the first half of the night, the vast majority of our ninety-minute cycles are consumed by Deep sleep, and very little REM sleep, as can be seen in the chart below from my Oura ring sleep-tracker. But as we transition through into the second half of the night, this seesaw balance shifts, with most of the time dominated by REM sleep, with little, if any, deep sleep.
This was my actual sleep data from a recent good night sleep. Notice the asymmetrical pattern; all 1 hour and 20 minutes of Deep sleep was before 2:30am, and most REM sleep occurred after 5:00am.
Early Birds v.s. Night Owls
The majority of the public is unaware of the fact Deep sleep occurs earlier in the night, followed by REM sleep which occurs near morning. This is a byproduct of our circadian rhythm – our built-in sleep-wake cycle. The fascinating thing about circadian rhythm is that it is built in to our DNA and has evolved over millions of years as a response to the earth's 24-hour rotation period. Effectively, we’re ruled by an inner clock that adapts to light, whether it suits our lifestyle or not.
So, based on all this information, is it better to be an early bird or a night owl? It's actually neither! Let’s go through a few examples – adapted from Matthew Walker's excellent book on sleep – to better understand why:
Say that you go to bed this evening at midnight. But instead of waking up at 8am, getting a full eight hours of sleep, you have to wake up at 6am because of an early-morning meeting. What percent of sleep will you lose? The logical answer is 25%, since waking up at 6am will lop off two hours of sleep. But that’s not entirely true. Since you get most of your REM sleep in the last part of the night, you will lose 60%-90% of all your REM sleep, even though you are losing 25% of your total sleep time. It works both ways. If you wake up at 8am, but don’t go to bed until 2am, then you lose a significant amount of Deep sleep. Similar to an unbalanced diet in which you only eat carbohydrates and are left malnourished by the absence of protein, short-changing the brain of either Deep or REM sleep—both of which serve critical, though different functions—results in a myriad of physical and mental ill health. When it comes to sleep, there is no such thing as burning the candle at both ends—or even at one end—and getting away with it.
Based on this, think before you join the 5am Club, regularly waking up before dawn is a surefire path towards cognitive decline.
So here is the hidden lever: When thinking about sleep efficiency, use the Goldilocks principle, not too late and not too early.
Stay tuned for Part 2 and Part 3 on circadian health and optimizing your sleep routine.
Until next time,