The following is an excerpt from Dave Asprey’s new book, Game Changers: What Leaders, Innovators and Mavericks Do to Win at Life, which analyzes hundreds of interviews Dave has conducted with high-performance leaders to distill 46 science-backed laws to help people become more successful, healthier, and happier.

There is no morality in waking up early or staying up late. There is a huge amount of power in finding out when you sleep best and then building your life so that you can sleep.

To learn as much as possible about every nuance of sleep, I began by interviewing Dr. Michael Breus, a clinical psychologist, best-selling author, and well- known sleep expert who has spent his entire career treating sleep disorders. When he was starting out, Dr. Breus wanted to stay away from pharmaceuticals as much as possible, so he experimented with many different techniques to treat his insomnia patients, including natural supplements and cognitive behavioral therapy. Those treatments worked for some patients, but many others saw little or no improvement. So he got to hacking.

Dr. Breus was determined to figure out what was preventing those people from sleeping, and after studying their sleep patterns and hormone levels, he realized that they were often sleeping well, but they were going to sleep and waking up at the wrong times. It turned out that they weren’t insomniacs at all. Their bodies were able to naturally sleep for a full six-and-a-half- to seven-and-a-half-hour sleep cycle, but they were going to bed either too early or too late and their bodies weren’t able to sync with their schedules.

It’s not as if those people were purposefully or carelessly messing up their sleep. They created their sleep schedules based on logistics — they had to get up early to go to work, take care of their kids, or go to school, just as most people do. But Dr. Breus felt confident that they would be more alert and productive if they were able to go to sleep and wake up in accordance with their bodies’ natural circadian rhythm, which is the brain’s sleep/wake cycle. Inside our brains is an internal clock called the suprachiasmatic nucleus (SCN), which determines when we’re sleepy and when we’re awake. It does this by stimulating the release of certain hormones such as melatonin (the “sleep hormone”) at particular times of the day. This is an area of science (chronobiology) that is rapidly developing, and we’re gaining new insights virtually every day into just how much our circadian rhythm affects our health. In fact, in 2017 the Nobel Prize in Medicine was awarded to researchers who discovered a new protein that sets our body’s clock. We’re just figuring out how all this stuff works, but clinical physicians like Dr. Breus can see what works.

Dr. Breus was so sure that a simple shift in his patients’ schedules would help them sleep better that he actually called their bosses and asked if they would allow their employees to begin their workdays later if it meant they would be more productive. The bosses agreed and were thrilled when their employees’ levels of productivity did increase with their new schedules that allowed them to get more sleep.

That was the beginning of Dr. Breus’s fascination with The Power of When, which happens to be the title of his best-selling book about how to schedule your day around your natural patterns to maximize your productivity. He looked at his patients’ hormonal distribution throughout the day and helped them create customized schedules that allowed them to take advantage of their biology by doing things when their bodies were primed for those specific actions.

Dr. Breus found that some of his patients were skeptical. The value we attribute to being an “early riser” is so ingrained in our culture that we often fear changing our sleeping patterns. The early bird catches the worm, right? That is what we learn from a very young age — that if you get up early you’ll catch the worm and go about your day productively, and when the lazy, no-good bums who sleep late finally wake up, the worms will all be gone. Seems pretty bleak, and it is. We got that idea because when we switched to growing food instead of hunting it, if you didn’t get up early to work on your farm, you could starve to death. It’s insane that we never rethought the schedule, given the fact that today not nearly as many people work in fields.

But Dr. Breus explains to his patients that they won’t win by fighting Mother Nature. Your circadian rhythm is not just a preference; it is genetically predetermined. Scientists have known about this since 1998, when they isolated the mPer3 gene and found that the first step of this gene’s expression showed a clear circadian rhythm in the SCN.3 Signals from the SCN synchronize miniature circadian clocks throughout the body. In other words, the mPer3 gene determines your sleep drive, and the SCN sets your circadian rhythm. When you work with those genetic factors instead of against them, everything becomes less of a struggle. This is one of the core principles of biohacking — working with your biology to make performance effortless.

Through this work, Dr. Breus identified four chronotypes, or behavioral manifestations of natural circadian rhythms. Instead of labeling them “early birds” or “night owls,” he matched these chronotypes with the circadian rhythms of other mammals. Indeed, only mammals have the mPer3 gene, and when it comes to our biological drives we have a lot more in common with other mammals than we do with birds. These four chronotypes are:


This is by far the most popular chronotype. A full 50 percent of people are bears. Their sleep-wake patterns follow the sun, and they generally have no difficulty sleeping. Bears are most ready for intense tasks smack in the middle of the morning, and they feel a slight dip in energy in the mid-afternoon. Overall, bears have steady energy and are good at getting things done. They work well within society and help things flow, and they can maintain their productivity all day as long as they use a mid-afternoon energy slump to recharge and don’t push past their natural energy limits.


Lions are the classic “early birds.” These are the go-getters who fly out of bed before the sun is up. They might not reach for a cup of coffee until a little before lunch, after their most productive hours have already passed. Because of their action-packed mornings, they tend to fizzle out in the evening and turn in early. They make up about 15 percent of the population.


Wolves are on the nocturnal end of the spectrum. They are the “night owls” who get a later start to their day and ride the productivity wave while the rest of the world is winding down. Interestingly, wolves have two peak periods of productivity: from noon to two in the afternoon and then again later, just as most of the working world is clocking out. Wolves tend to be creators — writers, artists, and coders. The creative areas of the wolf’s brain light up when the sun goes down. More often than not, wolf types tend toward introversion and crave their alone time. Sometimes they don’t feel like being the life of the party. Instead, they want to sit back and observe what’s going on around them. Wolves also make up about 15 percent of the population, the 15 percent best suited to hiring early birds to hunt for worms and bring them home in time for a late breakfast. (Okay, I’m a wolf. I’m writing this at 3 a.m., and it makes me happy. But I’ll sleep well tonight and get my six hours.)


Dolphins are the insomnia patients. They may or may not have a regular sleep routine, but they’re type A and often don’t get as much done as they want to during the day. Then they stay up tossing and turning as they ruminate over the day’s perceived failures. They’re also light sleepers who wake frequently throughout the night and struggle to fall back asleep. Dolphins’ high intelligence and tendency toward perfectionism probably explain why they spend so much time chewing over their days. They do their best work from mid-morning through early afternoon. Dr. Breus found that if his dolphin patients set up parameters around their sleep schedules, it helps them get back on track and start getting the sleep they need to be more productive.

You can take a quiz at to find out your chronotype, but there are other ways to figure it out yourself. Another guest on Bulletproof Radio, Dr. Jonathan Wisor, is one of the world’s foremost researchers on sleep and nervous system function. The Department of Defense and the National Institute of Neurological Disorders and Stroke funded his laboratory to apply molecular genetic and biochemical techniques to the study of sleep. Yet, somewhat ironically, he recommends an extremely low-tech method for determining your chronotype — simply taking a week off from work and going to sleep and waking up whenever you feel like it. Dr. Wisor believes that your circadian rhythm is such a strong biological drive that it will make itself sleep-wake even within this short time frame.

I bought into the “early bird” myth for a long time. Before I became a biohacker I spent my whole life working against my natural circadian rhythm and pushing myself to be an early riser. For two years, I forced myself to wake up at five in the morning and meditate for an hour. I truly believed that that was what it would take to be successful. But guess what? It didn’t make me more productive. It didn’t make me any happier. And it didn’t make me a better person. It just made me feel more tired and foggy and less creative.

It took years of tracking and hacking my sleep for me to realize that I’d been wasting a ton of energy trying to be a morning person. Instead of fighting my body by forcing it to sleep when it was naturally alert and wake up when it was naturally tired, I eventually learned to work with my natural rhythms, and guess what? I became more productive, happier, and more likely to outperform someone who was fighting his or her own rhythms to get that proverbial worm.

It was incredibly validating to talk to Dr. Wisor because it explained why I am stronger at night than I am in the morning. I am most definitely a wolf. I am at my most creative and productive late at night and perform better when I sleep until about 8:45 in the morning. In fact, I wrote most of this book (and my previous ones) between midnight and five in the morning, when everyone else was asleep, and I loved it. I am hopeful that with these scientists at the forefront of the current research on sleep, our society will finally begin to shift away from the old-fashioned “early bird” mentality and start allowing people to follow their body’s natural rhythms. I know that as a CEO I would much rather see my staff start working a couple of hours later and be more productive throughout the day than start early but without the energy to really bring their A-game. I believe that others would feel the same way if only they had this information, so I am grateful to Dr. Breus and Dr. Wisor for helping to get the word out about the importance of chronotypes.

Yet there is one variable that both doctors warn can disrupt your natural rhythms and make it difficult to stay true to your chronotype: light. Your chronotype is genetically based, but it is sensitive to light exposure. To learn more about this, I visited the lab of Dr. Satchin Panda at the Salk Institute for Biological Studies in San Diego. Before I interviewed him for the podcast, his grad students used an electron microscope to show special light sensor cells in the eye (called mela- nopsin sensors) that help set circadian rhythm. These light sensors pick up on light frequencies and send messages to the body to emit hormones based on the time of day. Interestingly, light triggers these reactions even in blind people. Dr. Panda has identified a single gene that controls the central timing system in the body and found a pair of genes that help keep eating and sleep in sync. That research helps to explain why the intermittent fasting recommendations in the Bulletproof Diet actually work. His book The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight is a treasure trove of information about what to eat when.

According to Dr. Panda, when the sensors in your eyes are exposed to full-spectrum light (such as the sun as it comes up in the morning), they send signals that prime your body to wake up, and when it is dark they signal your body that it’s time to sleep. This is one reason it is so important to make sure that your bedroom is completely dark at night. If the light sensors in your eyes pick up on even small amounts of artificial light at night, it can disrupt your sleep patterns by slowing down melanin production. In other words, your body won’t get the signal that it’s time to sleep. One signal your body expects before bed is red light, because that spectrum arises at sunset. When I’m home, I often use the Joovv light, a high-powered red and infrared LED light therapy device, before bed, which amplifies the “sunset signal” my body expects. The side effects of exposing oneself to those spectrums include better skin, faster healing, and deeper sleep.

It’s even more important to make sure you avoid blue light — the frequency that your smartphone, laptop, and tablet emit — in the evening. The light sensors in your eyes are particularly sensitive to this light frequency, and exposure before bed can ruin your quality of sleep even if you use an LED light therapy device. A simple hack is to use black tape (or special dots designed to look better) to cover all the lights in your bedroom so it is completely dark. I also recommend wearing TrueDark glasses before bed; these use layered optical filters to block every known spectrum of light that interferes with sleep, far beyond “blue blocker” glasses. (Full disclosure: I believe so strongly in this science that I backed the creation of the company. I have experienced a doubling of my deep sleep when I use them, and I’m wearing them as I type this sentence.) It’s also crucial to make sure that you are exposed to adequate sunlight during the day. When you’re exposed to daylight, your body produces serotonin, the “feel-good” neurotransmitter. Your body breaks serotonin down into melatonin, the hormone that helps you sleep. If you’re not exposed to enough natural sunlight during the day, you won’t develop enough melatonin to sleep well at night. This can mess with your circadian rhythm even if you follow the ideal schedule for your chronotype. Office windows, automobile glass, contact lenses, and sunglasses block vital spectrums of light that your body needs in order to regulate your internal clock, so it’s vital to get outside for at least a few minutes at a time several times every day!

Published with permission from GAME CHANGERS: What Leaders, Innovators, and Mavericks Do to Win at Life by Dave Asprey. 

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  • Dave Asprey

    Founder of Bulletproof, Author of “Game Changers,” bestselling author of "The Bulletproof Diet," biohacker

    Dave Asprey is the founder of Bulletproof 360, Inc., a leading-edge food, beverage, and content company, best known for the widely popular Bulletproof Coffee and starting the fat for fuel movement. He is a two-time New York Times bestselling science author, host of the Webby award-winning podcast Bulletproof Radio, and has been featured on the Today show, CNN, The New York Times, Dr. Oz, and more.

    He’s a self-made master of biohacking – a term he coined and has been recognized for creating in the Webster Dictionary for a concept he’s spent years testing on his own mind, body and brain. Over the last two decades, Dave has worked with world-renowned doctors and scientists to uncover the latest, most innovative methods for enhancing mental and physical performance by taking control of his own biology. The results speak for themselves: Dave has boosted his IQ by 20 points, dropped 100 pounds without dieting, and launched the Bulletproof empire including his unique line of health products, popular podcast and New York Times best-selling books. Dave has helped hundreds of thousands of people perform at levels far beyond what they’d expect, and without burning out, getting sick, or allowing stress to control decisions. Check out his new book "Game Changers" here.