Читать книгу Super Human: The Bulletproof Plan to Age Backward and Maybe Even Live Forever - Dave Asprey, Dave Asprey - Страница 13

4

SLEEP OR DIE

Sleeping feels good, but ever since I was a kid, there was always something more fascinating and productive I’d rather do than go to bed. I resented having to dedicate so many hours each day to something I saw as basically a waste of time. So for most of my life I skimped on sleep. Even the first two years after founding Bulletproof, I slept for about four hours a night, at most a self-imposed five hours. I used the extra three hours a day to be a father, start Bulletproof, and still pay the bills with my day job.

My sleep deficit almost certainly contributed to the diseases of aging I faced as a young man. It turns out that lack of quality sleep doesn’t just leave you tired and unable to perform in the moment; it also rapidly accelerates aging. The good news is that you can learn to be a Super Human sleeper and cram more high quality sleep into fewer hours and still get all the benefits. For the past five years, I have been getting progressively healthier, leaner, and younger on six hours and five minutes of sleep a night, but I use every technique in this chapter to sleep like a professional.

Perhaps you will choose to get more sleep than I do. Regardless of how many hours you sleep, the information in this chapter is intended to help you make the most of the sleep you do get. It doesn’t matter how old you are, how busy you are, or how much money you have. Sleep is the ultimate tool to sharpen every skill and add more quality years to your life. So get better at it.

HOW LACK OF SLEEP WILL KILL YOU

Like it or not, a lack of good sleep directly increases your risk of dying from one of the Four Killers. Meanwhile, just one good night of sleep can improve your ability to learn new motor skills by 20 percent,¹ and getting regular quality sleep increases your ability to gain new insight into complex problems by 50 percent.² This improved brain function could potentially help ward off cognitive decline with age and is befitting of a true Super Human. Good quality sleep also promotes skin health and youthful appearance,³ controls optimal insulin secretion⁴ (making you less likely to develop diabetes), and encourages healthy cell division.⁵ Sleep is an essential strategy in protecting against all Seven Pillars of Aging.

In the previous chapter we discussed Satchin Panda’s research on longevity and circadian rhythms. As part of my research for this book I went to his lab and had a great time with his PhD students looking at how the combination of food, light, and too little sleep affected rats. They walked me through new research showing that eating late at night dramatically reduced the quality of the rats’ sleep and that poor sleep impacted the rats’ ability to control blood sugar by up to 50 percent. That’s huge! In fact, it’s more than what most medications can do.

In rats and humans, the pancreas is responsible for making insulin. Satchin has studied insulin-producing cells in the pancreas and found that they, too, have their own circadian rhythm. At night when melatonin, a hormone that helps regulate wake and sleep cycles, is released, insulin-producing cells shut down, too. So if you eat something sugary late at night, your body’s insulin response is not as effective as usual. So that late-night piece of cake leads to a blood sugar spike and then a crash that triggers the release of adrenaline … which keeps you awake at three A.M.

If you get less than six hours of sleep, the hormones that control how hungry and/or satiated you feel (ghrelin and leptin, respectively) start to work against you. Ghrelin increases, making you feel hungry, and leptin decreases, making it more difficult for you to feel satiated. This is one reason that sleep loss leads to obesity and all the many health problems that go along with it.⁶

Sleep is also incredibly important for warding off Alzheimer’s disease, the killer many of us fear most as aging begins its silent creep. When you are asleep, your brain undergoes a natural detoxification process. The glymphatic system, a waste clearance pathway comparable to the lymphatic system, which drains fluids from tissues in the body, sends cerebral spinal fluid through the brain’s tissue and flushes out cellular waste and neurotoxins.⁷

This is a big deal, as the glymphatic system clears out the amyloid proteins that are the hallmark of Alzheimer’s when they build up in the brain. While we don’t yet have hard evidence that Alzheimer’s disease is caused by a lack of sleep and thus not enough time for the glymphatic system to work its magic, I would wager that it’s a contributing factor. In fact there is some evidence of this. A small study on twenty human participants showed that losing just one night of sleep causes an increase in amyloid proteins in the brain.⁸ That may be a small sample, but it’s enough to convince me to make sure my glymphatic system has a chance to fully detox my brain each night. That doesn’t mean sleeping for eight hours; it means sleeping like a boss.

Since mitochondria play a role in the glymphatic system process and sleep in general, everything you do to strengthen your mitochondria can also help you sleep better and thus keep your brain clear of amyloid plaques. There are also simple things you can do to enhance your glymphatic system function. For example, studies on rats show that sleeping on one’s side improves glymphatic clearance compared to sleeping on the stomach or the back.⁹ While we don’t have studies proving that this transfers to humans, we know that side-sleeping humans have lower blood pressure and heart rate.¹⁰ Sadly, they also get more vertical wrinkles than back sleepers, but sleeping on your back increases your risk of sleep apnea, a condition in which the upper airway becomes blocked during sleep. Sleeping on your back will make you less wrinkled but more likely to die. Not a great trade-off. I’d opt to stay alive and hit those wrinkles with other hacks in this book.

Apnea in and of itself puts you at a much higher risk of dying from one of the Four Killers. Sleep apnea is often the result of dysfunctional mitochondria, and it can be deadly.¹¹ If you snore, your risk of developing diabetes, obesity, and high blood pressure is nearly double that of someone who does not. And if you snore and you wake up feeling groggy and/or have trouble falling asleep, your risk goes up 70 to 80 percent, respectively.¹²

As you read earlier, bad quality sleep causes poor blood sugar regulation. It’s also true that dysfunctional mitochondria cause bad sleep, which then causes poor blood sugar regulation! No matter how you slice it, if you don’t get enough good quality sleep, you will age faster and die sooner. Which begs the question …

HOW MUCH IS ENOUGH?

When I learned about how critical good quality sleep is to aging well, my perspective on sleep changed for good. Instead of seeing it as something to skimp on, I made it my goal to hack my sleep so I could get all of the benefits of a good night’s sleep without having to sacrifice eight hours of my life every night. Some of these efforts have been more successful than others.

In the year 2000, when Google was just eighteen months old, an early biohacker posted the Uberman Sleep Schedule in a dark corner of the Internet. This was the first writing to propose that you could get away with only three hours of sleep per day as long as you were willing to sleep in several carefully timed, precise naps at exactly the same times each day. This technique is now called polyphasic sleep.

Intrigued by the approximately eleven years of my life I’d reclaim from this schedule, I tried it. The amount of time and energy it takes to do this is absurd, not to mention the social and professional interruption from napping at the same time every day and feeling wrecked if you miss one nap. Polyphasic sleep is not compatible with having either a career or a social life. Some people have success with it, but personally I felt like an unproductive, antisocial zombie. The idea of getting by on a couple of hours of sleep at a time is a beautiful dream (get it?), but it just didn’t work. I was starting to feel resigned to having to sleep eight hours a night …

Then I came across a study from the Keck School of Medicine of USC and the American Cancer Society that looked at over 1 million adults ranging in age from thirty to a hundred and two and correlated how much they slept with their mortality rates.¹³ The results of this study changed the way I thought about sleep forever. The data was actually collected in the 1980s, but it was so complex, showing differences in outcomes with just a half-hour difference in sleep length, that they couldn’t crunch it all with 1980s computing, so the information sat there for years until researchers could use high-speed computing. The researchers found that the people who lived the longest slept six and a half hours a night, while people who slept eight hours a night consistently died more from any cause. Ha! Take that, all you doctors who told me I had to sleep at least eight hours each night!

You might hear this and draw the conclusion that in order to live longer you should simply sleep less, but that is unfortunately the wrong conclusion. What you can take away from that study instead is the fact that the people who lived the longest were the healthiest people. They required less sleep because they didn’t need as much time to recover from chronic illness, inflammation, and/or everyday stress. If aging is “death by a thousand cuts,” sleep equals recovery from many of those “cuts.” The fewer cuts you need to recover from, the less sleep you need.

I started using my sleep length and corresponding energy levels to measure whether I was doing things during the day that made me older. I knew that if I jumped out of bed ready to bring it after six hours of sleep, I was on the right track. But if I felt groggy after a solid eight hours of sleep, that meant I was probably doing something that made me sick and inflamed. This explains why I needed less sleep when I started following the Bulletproof Diet. I was taking fewer hits from the foods I ate, so I didn’t need as much recovery time.

This became a two-step process. Step one: Reduce the number of hits I took so my body required less recovery time. Step two: Increase the return on my sleep investment by improving its quality. Bottom line—if you’re healthy enough, you can use sleep strategically as a performance-enhancing drug instead of a drag. You still have to get enough sleep, but the other hacks you’ll use to become Super Human will reduce the number of hours of rest you actually need.

HOW WELL DID YOU RECOVER LAST NIGHT?

In order to work on improving the quality of my sleep, I began a long journey of understanding my sleep, a journey that is still going strong after nineteen years. There are all sorts of reasons to pay attention to your sleep. If sleep is recovery, you need to know how well you recovered last night so you can make an informed choice about what actions to take today. For instance, if you know you slept poorly, a heavy workout will age you instead of making you stronger; a high-sugar meal will impact your blood sugar even more than usual; and even small amounts of stress will be damaging.

Quality sleep is like having money in your recovery bank account. Can you imagine not checking your bank account on a regular basis? If you can see where your sleep stands today, you can zero in on small changes you can make to improve your sleep, recover better, and stay young tomorrow.

In 2004, I was finishing a brutal two years that had me working full time while enrolled at an Ivy League business school. Sleep was in short supply, as you’d imagine. So I became one of the first purchasers of an expensive headband that tracked my sleep and told me exactly how well I did every night. The data was enlightening and helped inform many of my early biohacking practices. Unfortunately, Victoria’s Secret definitely did not approve of these early tracking devices (and neither did my wife). Thankfully, there has been quite an evolution in the quality and attractiveness of sleep trackers since then.

Seven years later, I became the chief technology officer for a wristband sleep and exercise tracking company called Basis (which Intel has since acquired). Before most people were wearing wrist trackers, I was able to track my sleep, make strategic changes, and get more out of the time I spent with my eyes closed. In fact, I’ve purchased and tried just about every sleep tracker on the market. A sleep tracker is an anti-aging device with one of the highest ROIs. I promise that you have no idea what your brain is doing while you sleep. Before we get to what technology to use, ranging from free to a few hundred dollars, it’s important to know what you are looking for when you track your sleep.

SLEEP BASICS

Of course you want to know exactly what time you fell asleep, what time you woke up, and how this information varies over time. Did it take you a long time to fall asleep after you went to bed? Did you wake up several times during the night even if you don’t remember them? Are you wasting your night with light sleep? These are all important factors in determining the quality of your sleep. When I did the crazy “zero carbs for nineteen days” experiment, my unattractive headband sleep tracker showed me I was waking up eight to twelve times every night, yet I had no recollection of waking at all. I did feel like a zombie in the morning, though. It was my sleep data that eventually made me quit that experiment!

It’s also worth paying attention to snoring when tracking your sleep for all the reasons mentioned above, particularly because snoring is a sign of inflammation. I used to snore terribly because the back of my throat was inflamed and partially blocked my airway. Now I don’t normally snore more than a couple of minutes a night, and I am usually able to connect it to something I ate the day before that caused inflammation. I also get a handy recording of my snoring so I can’t deny that it’s happening! This is incredibly valuable information because food that inflames your throat also causes aging inflammation throughout your body.

REM/SLOW-WAVE SLEEP

When you’re sleeping, you cycle through two types of sleep each night—rapid eye movement (REM) sleep, which is when you dream, and non-REM (NREM) sleep. NREM sleep comes in three flavors: crappy (stage 1 useless light sleep), decent (stage 2 middle sleep that is still considered light sleep), and awesome (stage 3 deep delta sleep). To age or perform like a Super Human, it’s your job to spend as much time as possible in deep or slow-wave delta sleep. This is when your breathing and heart rate drop to their lowest levels and your brain waves slow down and get wider (as measured by a test called an electroencephalogram, or EEG). These slow waves are known as delta waves, and your brain produces them at a frequency of 1 to 4 hertz, a unit of measurement that is equal to one per second. To put that into context, gamma waves, the fastest brain waves, have an average frequency of above 40 hertz.