Why We Study Sleep

This post is adapted from a speech delivered at a Fireside Chat between Arianna Huffington and Andre Iguodala on April 11, 2016 at Stanford University. You can watch the event here.

Before introducing our famous guests, as director of the Center for Sleep Sciences and Medicine, I have been asked to introduce the topic of sleep and sleep disorders and why we should bother to study sleep. This is not difficult for me as sleep is my passion.

The first reason for studying sleep is simply that sleep is one of the last remaining mysteries in biology. We still don't understand why a typical human has to spend 25 years of life sleeping. Or why sleep deprivation is still such a powerful force that can lead people to collapse or make terrible errors of judgment. It is also a magical moment that allows us to disconnect from the world, hunger, worries, etc. "Sleep is death without commitment," says the humorist, and I guess this is why it is so stressful not to be able to sleep when you have problems in your life. As I will discuss toward the end of this presentation, I believe these answers are within our grasp with relatively limited investment thanks to advances in big data and genetics.

At the practical level, we know that two distinct processes, circadian timing and "sleep debt" regulate sleep. Sleep debt is what we feel when we stay awake for a longer and longer period of time. Day after day, people become more and more tired so that after three nights a person would literally kill just to catch a wink. Our brain keeps track of how much sleep we have and makes it imperative to catch up. Randy Gartner was able to stay awake for 264 hours (11 days), which is the world record. This is strange as sleep makes us vulnerable to predators, and in fact carnivores on top of the food chain sleep the most. Literally nothing is known regarding what controls sleep debt and sleep needs in individuals or how the brain keeps tracks of it. We just know that sleep needs varies a lot with age and between people and that sleep makes us feel restored. But exactly what it restores in the body and the brain is unknown. Could you imagine a world where you could take a pill, fall asleep quickly, sleep for only a few hours and awaken fully rested? We are far from it.

Independent of our sleep debt, we feel much worse at certain times of the day and night. For example, even when we do not sleep for several days, it is much easier to stay awake in the early evening while in the early morning we feel very sleepy. This feeling parallels change in our body temperature and are what we experience during jet lag. Unlike sleep debt, we do know how circadian rhythms are generated; the problem is that no one has been able to simply apply this complex knowledge to help people. What has been discovered is that almost every cell in the body has an internal clock that allow it to get ready for the new day, and that this clock works by producing factors that cascade into regulating other factors. This process takes exactly 24 hours to complete and reset. We also know that all these clocks are regulated by a master clock located in the suprachiasmatic nucleus or SCN. The SCN is a part of the brain located above the optic nerve that is directly connected to the eyes so that light can reset our clock to the right timing everyday, which is important because otherwise our timing would drift everyday. It is also what helps us adjust to jet lag when we are travelling across time zones. For all of you world travelers I hope you know that the most efficient way to reset your clock is to stay outside and get as much daylight as possible.

What is also interesting is that circadian rhythms don't simply make you more awake during the entire day and sleepier during the entire night; they cleverly work together with our sleep debt to optimize the 24hr cycle. For example, in the morning, people are awake mostly because they just slept and have no sleep debt, but as the day progresses and the temperature rises so does sleep debt and in the evening people are awake because the circadian clock is making us alert, fighting the sleep debt we have accumulated since the morning. The opposite occurs at night, we sleep when the sleep debt is too high, and then stay asleep longer in the morning because temperature drops and the circadian clock makes us sleep a few hours longer. This is why in the middle of the day or the night we have vulnerability zones when we can nap or have the tendency to wake up.

As you can tell, a lot of things happen during sleep, and to top it all, we actually have two different types of sleep that we need, slow wave sleep and Rapid Eye Movement (REM) sleep. During a typical night, the normal sleeper will first fall asleep in a stage of sleep where the cortex rests and generates increasingly big synchronized waves-this is why it is call slow wave sleep. This stage of sleep is associated with a disconnected cognition, so that if one wakes up the subject during slow wave sleep, he would be confused and not thinking much. This is also the stage of sleep people are half in when they sleep walk or have night terrors. After about 1.5 hours, something strange happens and the brain switches to a state called paradoxical sleep or REM sleep. This is a strange state as the sleeper is completely paralyzed, but his eyes move furiously, and he dreams so that the cortex is as active as when awake. Amazingly, this state of being was only discovered 70 years ago. In fact, our prior director, Dr. William C. Dement, witnessed the phenomenon and reported REM's association with dreaming. Dement is often considered as the father of sleep medicine. In REM sleep, the most basic parts of the brain that regulate automatic functions are disconnected. For example, temperature or muscle tone, are switched off. In contrast, the cortex is over activated, possibly to increase random connections and also to increase our creativity. Whereas we have some idea about the function of SWS as we rest and save calories, REM sleep is still a real mystery.

The second reason why we need to study sleep is that approximately 20% of the population has serious sleep problems and currently we don't have very good solutions to offer. The most common problem is sleep apnea, which affects 10% of the population, especially men and is linked to being overweight or having a small chin that makes the airway narrower. I know that you may think it does not apply as much to you, but you might be surprised as we also see it in people of both sexes and even children. In sleep apnea, the negative pressure we produce when we breathe makes the airway collapse. Sleep apnea produces two problems: bad sleep and being tired all the time; and more worryingly, when the oxygen drops a lot during the night, increased risk of stroke, heart attacks and even death. Sleep apnea is a difficult diagnosis because the main treatment, continuous pressure airway therapy-CPAP-is for many worse than the disease. It is a very simple treatment; a pump pushes the air gently into a mask that prevents the airway from collapsing. The problem with CPAP is that half of the patients cannot tolerate it. Although we have other effective therapies such as surgery or dental appliances the problem is that it is impossible to know for sure who can benefit from which of these and, of course, there is a great need for precision in this area.

A second common problem, this one more often affecting women, is insomnia. Insomnia is often considered as a hopeless condition, which is really wrong. We made a lot of progress in treating insomnia without medications. Indeed, a subset of insomnia patients develops a bad pattern where they try too hard to sleep, staying in bed for too long and worrying too much about it. In these cases, cognitive behavioral therapy and sleep restriction can be very effective and life changing. We simply ask them to log in how many hours they sleep for about 2 weeks and calculate the mean. We then reorganize their schedule so that they end up with a slightly lower total amount of sleep thus that sleep stays consolidated. This breaks the vicious cycle and they can relearn to sleep soundly.

Beside sleep apnea and insomnia, we also see a whole array of more uncommon problems, for example restless syndrome a condition where a person feels the need to move their legs in the evening and at night. It is a genetic disorder that is also linked to iron deficiency. We also see patients who have the opposite of insomnia, they struggle to stay awake during the day and have very vivid dreaming experiences, such as in narcolepsy. Others have strange behaviors during sleep, such as kicking or acting out their dreams, or walking or talking in their sleep. Some patients with sleepwalking have jumped out of windows, slept in the wrong bed, etc., which I am sure you can imagine, can have devastating consequences.

The third reason why we need to study sleep is that sleep is involved in everything we do. And yet, as our invitees will illustrate, it is dangerously underappreciated. An increasing number of people work night shifts, have 2 jobs or in your case study too hard at the expense of sleep. To cheat on sleep increases risk for all kinds of problems - obesity, diabetes, cardiovascular problems and even cancer, not to mention marital problems or car or industrial accidents. Car accidents may be one of the most tragic consequences, and because sleep is so much stronger in younger individuals, you all are particularly at risk. Falling asleep at the wheel is even more deadly than accidents involving alcohol. When we fall asleep at the wheel, it lasts several seconds and I am sure you can imagine what it does when a car is traveling at sixty miles an hour on the freeway without even attempting to brake. Personally, I cannot wait for self-driving cars so that I can nap on my way home after a party.

Unfortunately it is also macho for high-powered executives and leaders to underreport on their sleep and this has a bad influence all around. There are countless examples of people bragging they only sleep a few hours. Napoleon, for example claimed to only need a few hours of sleep. On another hand, he clearly made an error of judgment in closing the Louisiana Purchase deal with Jefferson; otherwise, you, the audience, and not me would be the ones with a strange accent.

My passion is now to use genetics and machine learning on large datasets of sleep studies or sleep devices to crack open the mystery of the molecular mechanisms of sleep and the causes of sleep disorders. With all this in mind, I could not believe how lucky we were when I was first contacted by Arianna and found that we could work together to improve sleep for all Americans. Who could have dreamt of a better champion! I would not want to steal Arianna's thunder and explain how she got interested in sleep, and what she does to make sure it is optimized. Suffice it to say that she has lived and continues to live a passionate life full of hard and creative work, and that she has been rewarded by many successes. She is an incredible role model for all of us and I am thrilled she called her book the Sleep Revolution since as a French man; I understand the power of revolution. Statistically speaking, many of you suffer from sleep problems. The revolution that Arianna is bringing to you is that you can start today to do something about it.

Not only are we lucky enough to have Arianna with us but we also have with us André Iguodala who needs no introduction. As you must know Andre is a Golden State Warrior and was last year's NBA Finals MVP. His team is on the way to breaking records this season. He will share with us how taking sleep seriously has changed his performance. André, we are all rooting for you on Wednesday!