READ THE ARTICLE AND ANSWER THE QUESTION ARTICLE: Its Not You; Its Your Schedule

Tell me your daily routine, and Ill tell you how healthy you feel. Tell me when you eat, and Ill tell you if it is easy or difficult for you to maintain your weight. Tell me when you exercise, and Ill tell you whether you are building your bodys systems or wearing them down. Tell me when you turn off your television or computer at night, and Ill tell you how sensitive you are to stress. Tell me when you fall asleep, and Ill tell you whether you need coffee to power your way through the afternoon, or whether you snap at your loved ones at the end of a long day when you wanted to be patient. Does this sound like magic? Its not. A growing body of science reveals how closely our bodies are linked to the circadian rhythm of light and darkness, right down to the cellular level. This research shows that when you eat is as important as what you eat, when you fall asleep is as important as how much sleep you get, and when you exercise is as important as how much exercise you get. Your daily schedule determines your weight, your stamina, your general health, and your mood. Dont believe me? For decades, diabetes researchers have known that a simple way to trigger obesity in laboratory mice is to wake them up and feed them during their sleep cycle. In fact, mice gain weight within a week if researchers just expose them to low-level lights when they should be sleeping.1 Still dont believe me? Think back to the last time you experienced jet lag. How did you feel? Anyone who has experienced jet lag knows the

symptoms can go far beyond sleep disruption. Often, you suffer from constipation, upset stomach, cognitive fog, low energy, and an increased sensitivity to stress. A recent study even linked jet lag to weight gain because disrupting your schedule through long-distance travel confuses the microbes in your gut.2 Yet these same complaintsweight gain, insomnia, exhaustion, stress, depressionare the very things that bring people to my clinic. And, if youre reading this book, Id guess that these complaints sound awfully familiar to you, too. Thanks to the demands of modern jobs and 24/7 connectivity, many of us live in a constant state of self-imposed jet lag, sleeping, eating, and exercising at times that dont coincide with the bodys natural rhythms. But there is good news, and Im here to tell you what I tell all my patients: Its not you; its your schedule. There is an easier way to lose weight, get energized, and get to sleep at night. By working with your bodys natural rhythms and not against them, you can create a daily schedule that will transform your health and your life.

The Circadian Rhythm

Physiologists know that the body has a natural rhythmcalled a circadian rhythmthat operates on a nearly twenty-four-hour cycle, resetting itself every morning when you first experience daylight. This rhythm directs the body on when to digest food, how to prepare for sleep, and how to regulate everything in your body including blood pressure, metabolism, hormone production, body temperature, and cellular repair. Your skin cells, too, repair and regenerate on a daily schedule. Even the population of microbes in your intestinal tract changes profoundly throughout the course of a single day. Certain strains of gut bacteria proliferate during the day, while others predominate at night. At every hour of the day, your body is changing its function. The cells and systems are primed to do different things, depending on the time of day or night. Thats how we know that you hit your deepest sleep cycle at about two a.m., that your body temperature is lowest at about four a.m. Your bodys sharpest rise of blood pressure comes at about six forty-five a.m., and a bowel movement is most likely at eight thirty in the morning. By ten in the morning, your mental alertness peaks, and your digestion is operating most efficiently at noon. Your coordination, reaction

time, and cardiovascular strength peak in the afternoon while your digestion powers down. After sunset, your blood pressure hits its highest daily level, along with your bodys temperature. At about nine p.m., your brain starts releasing melatonin, and your digestion slows to half speed. By ten thirty, your bowel movements are suppressed, and your digestion is at a crawl. This happens, or should happen, every day. This is why your body gets so confused when you cross time zones. The light changes and the body loses its compass for controlling all of these bodily functions. This is fascinating because we think we are so isolated from nature. We live in climate-controlled homes and work in offices or cubicles. And yet every system in our bodies is changing in a predictable, daily pattern. Your body is always trying to coordinate all of its systems on a central clock using available natural light. Every organism in nature operates in this cyclical way, and a new field within biology, called chronobiology, studies all the ways in which different organisms operate in accordance with a circadian rhythm. What researchers are studying now is how our daily habits interact with this circadian rhythm, and theyve discovered that the modern schedule profoundly disrupts it. Staying up late at night watching TV or doing work fools your body into thinking that night hasnt started yet. Eating a big meal in the evening does the same thing. It delays the cycle and disrupts sleep, only to have you jolt the body awake first thing in the morning when your alarm goes off. Lack of exercise and natural light further disrupt the circadian rhythm, which in turn disrupts everything from your digestion to your hormone secretion and your nervous system. Many of my patients routinely stay up until midnight, working and snacking, and then wonder why they cant fall asleep until one. Then they drag themselves out of bed at six a.m. and wonder why they cant eat or concentrate in the morning. A couple of hours of deviation from your bodys natural rhythm may not seem like much, but to put this in perspective: if you only sleep between one and six a.m., its as though you flew from California to New York in the evening, only to fly back before work. No wonder you feel sick. Many of our most common physical complaints are created or exacerbated by a modern schedule at odds with the bodys needs. Fortunately, physiologists have generated a lot of new research about the bodys clock and how behavior either helps strengthen the clocks signals or

gets in its way. This new field is called chronobiology, and it offers insights about how you can set a daily schedule that will keep you healthy and energized.

How Your Body Tells Time

Your body always knows what time it is, even if you dont. It may sound absurd to think that you dont know what time it is. You are probably hyperaware of the time at every moment of the day. You have a train to catch or you have kids to drop off at school. You have a meeting in fifteen minutes and a call in an hour. You have to get to the dry cleaner before it closes. You have project deadlines, dinner reservations, and an alarm clock (or two) that wakes you every morning. My patients tell me that they are constantly aware of the time and that the clock dictates nearly every one of their daily activities. But there is a different kind of clock inside your body, one that rules all of its cells and systems. To understand how it works, you have to step inside the brain and into the hypothalamus. The hypothalamus sits at the center of the brain and is responsible for regulating all of the bodys systems. It activates the fight-or-flight response when you feel stress or danger. It tells you when you are hungry or thirsty. When you begin a strict diet, the hypothalamus is whats telling you that you are starving because you are eating differently. You may know that you arent starving, but the body is signaling to the brain that its not getting the same amount of food as before. When you start a new exercise routine, the body signals muscle fatigue and cardiovascular stress to the brain an the hypothalamus urges you to stop. And when you stay up late to work on a project, the hypothalamus is whats telling you that you are sleepy and bored. So this part of the brain can read the bodys signals and try to affect your behavior, trying to keep everything the same as it was yesterday. The hypothalamus also regulates all kinds of things that you dont consciously control, including body temperature, hormone balance, and metabolism. All of these changes happen at predictable times of day. For example, your body temperature peaks in the evening, then decreases during the night and reaches its lowest point just before dawn. Your blood pressure rises sharply as you wake up each morning, and then increases

slowly throughout the day before falling during the night. The sharp rise of blood pressure in the morning comes at a time when blood platelets are stickiest, which explains why many heart attacks happen first thing in the morning. Cortisol levels, too, change at predictable times. Cortisol is a steroid that the body produces and its sometimes called the stress hormone. The level of cortisol in your body is lowest when you go to bed and then accumulates during the night. It is partially responsible for your bodys inflammatory response, so its no wonder that those aches and pains are at their worst when you get out of bed, or that you feel most bloated and puffy in the morning. Cortisol levels discharge steadily throughout the day, fluttering briefly upward after every meal. Colonic motilitywhich is a fancy term for bowel movementschanges during the day as well. First thing in the morning, the colon wakes and moves at three times its normal level of activity, with predictable results. Thats why so many people feel constipated while in the throes of jet lag. A poor eating schedule can also confuse the colon. At night, the colon rests and bowel movements are suppressed. Mood and brain waves alter throughout the day and night as well. In order to regulate the bodys systems, your hypothalamus takes its cues both from the bodys tissues and organs and from the environment. When you smell food, you feel hungry; when you see danger, you feel anxious and energized for action. All true. But lets dont forget the most pervasive signal the brain takes in all daythe presence of light. There is a small part of the hypothalamus, called the suprachiasmatic nucleus (SCN) that is tasked with noticing light. Its about the size of a grain of rice, and it contains approximately twenty thousand neurons. Physiologists have long understood that these neurons respond to light and regulate the bodys systems based on light and darkness. When light hits the retina of the eye first thing in the morning, the SCN signals to the body that its daytime. In the evening, the SCN helps signal the bodys natural production of melatonin that tells you when its time for sleep. But its only in the past twenty years that researchers have looked at how much power this tiny bundle of neurons exerts over every cell and system in the body.

A Brief History of Chronobiology

In order to appreciate the field of chronobiology, we have to travel back almost three hundred years, to an experiment carried out by the French scientist Jean-Jacques dOrtous de Mairan. In 1729, de Mairan became interested in the way that some plants open their leaves in the sunlight and close at night. So he exposed these plants to constant darkness and observed them. They continued to open their leaves in the morning and close them at night even though it was dark all the time. Their leaves moved as though expecting the sunlight that never came. De Mairan was baffled, and so were the many researchers who replicated his experiment. Another scientist referred to the closing of the leaves as a kind of plant sleep. The plants continued to open and close their leaves on schedule for many days after sunlight had been blocked. De Mairan wondered if the plants could somehow sense the sunlight aboveground. He didnt go so far as to suggest that the plants had a cellular predisposition to open their leaves at a certain timeit would have been heresy to suggest such a thing, and it remained a kind of heresy for about two hundred years. Instead, de Mairan wondered if ambient changes in temperature or the rotation of the earth was informing the behavior of these plants. A bigger mystery was why the natural rhythm of opening and closing didnt follow a twenty-four-hour period. Eventually, when scientists could study the plants more closely, they found that these movements became less pronounced in total darkness, and the plants opened and closed their leaves on a twenty-two-hour cycle. But when the plants could experience light, they reverted to a twenty-four-hour cycle. This suggested that they somehow have a biological predisposition to move in anticipation of light, and that the light itself helps them synchronize their internal clocks. It was easy to theorize about how light and darkness affect plants because they need light, but it would take a particular kind of scientist to notice that other types of organisms, including mammals, also use light to alter their physiological function. That scientist turned out to be a young Romanian doctor named Franz Halberg, who was completing a fellowship at Harvard in the late 1940s when he began to track the levels of circulating white blood cells in mice. He continued his research at the University of Minnesota, where he noticed that the white blood cell count peaked during the day and fell at night. Different strains of mice had different levels of circulating white blood cells, but every type of mouse showed the same pattern of sharp rise during

the day and a similar fall at night. Soon, Halberg was tracking hourly fluctuations in blood pressure and heart rate in the mice, along with body temperature, and found that these physiological responses varied on a similar twenty-four-hour schedule. By 1959, he had coined the term circadian rhythm to account for these changes. Over the ensuing decades, he theorized about and then proved similar variations in humans.3 Halberg found that a host of physiological processes, including body temperature, hormone production, blood cell counts, blood pressure and heart rate, glycogen levels in the liver, even cell division, all vary along predictable patterns, all of which seemed to him to be light-dependent. But genetic research was still in its infancy, and few researchers wanted to believe that the body contained an internal clock that varied with time of day or with seasons of the year. Halberg was certain that fluctuations within these patterns were possible markers for disease. He believed that monitoring blood pressure constantly gave a better prediction for heart attack and stroke than taking a single measure in a doctors office. Thats why he monitored his own blood pressure every thirty minutes each day for the last fifteen years of his life. Perhaps he was on to something. He lived to be ninety-four. He further theorized that anticancer treatments would be most effective when the core temperature of tumors was highest. He believed that the body operated entirely on a circadian rhythm, and that nutritionists and medical doctors should consider these rhythms as part of any treatment plan. And although chronobiology centers sprang up in major research centers all over the world, it was difficult to prove the efficacy of these theories until the very end of the twentieth century. Halberg himself found it difficult to secure funding for his studies, and to get the subject of chronobiology taught in medical school. It would be tempting to say that the rest of the medical community dismissed these theories. But the truth is that at the time it was expensive to constantly monitor blood pressure, blood counts, glucose uptake in the liver, and other physiological responses. Halbergs theories ranged far ahead of technology, and it would be up to geneticists to explore these ideas and figure out exactly how the cells in the body are able to coordnate with the SCN each day and night.

Clock Genes

We now know that the cells in the body contain what are known as clock genes. They have specific names, such as per1, per2, per3, which are active at night, or CLOCK and BMAL1 genes, which are active during the day. They operate on a kind of loop. The activity of one of these clock genes inhibits the activity of the other. Your cells are primed to do different things based on the light and dark cycles of the day. And the protein pathways for each of these cells is active or inactive based on the time of day. Every morning when you open your eyes and see daylight, your SCN is giving the signal to reset the internal clock and sends information to all of the systems of the body and all of the organs and tissues to say that its daytime again. And this clock sets the automatic physiological changes that must occur on time for the next twenty-four hours in order for the body to function. In this way, the SCN is the brains clock. Or perhaps we should say that it is the brains master conductor, and all of your bodys cells are trying to dance to its beat. While the master clock in your brain is trying to set a total body rhythm, the cells in your body are reacting to your behavioryour sleep schedule, your mealtimes, and your activityto set their own clock rhythms. When the brains clock and these cellular clockscalled peripheral clocksare out of alignment, you can get distorted cell behaviors. Remember those mice who gained weight when they were fed during their sleep cycle. Their bodies were operating outside the master circadian rhythm, taking in nutrients that the cells in their digestive tract couldnt process. And the reduced sleep schedule meant that on a cellular level, whole systems in their bodies stopped functioning the way they were supposed to. This causes disruptions not just in the digestive process, but in hormone production, immune response, and inflammatory response. As you can imagine, this puts an entirely new spin on the field of epigenetics and how our behavior alters and affects genetic expression over time. As a field, chronobiology is still new, but clock genes seem to have an effect on aging and tumor suppression in addition to metabolism. Eating and sleeping at the wrong time disrupts the circadian rhythm and interferes with a healthy metabolism and a strong immune response. Though scientists are still working out many of the nuances and clinical treatment

applications, what we know for certain is that you can use your daily schedule to reinforce the circadian rhythm and achieve better health. Even without the presence of light each morning, your body would try to function on that same twenty-four-hour schedule. Starting in the 1970s, researchers did experiments with people who agreed to live in isolation without daily exposure to natural light. (Unlike de Mairans plants, they agreed to go live in a cave.) A number of findings have emerged from these experiments over many decades. First, the bodys clock will drift without the daily reset of natural light and darkness. The primary means by which the body sets its circadian rhythm is through light. Second, the body can use social cues, such as timing of meals, sleep, and exercise, as a substitute when light signals are absent. All of the bodys attempts to synchronize its systems onto a single master circadian rhythm are called entrainment. The body relies on signals to help it reset the circadian rhythm and keep itself functioning optimally. While it prefers to use light and darkness as the primary signal, it can and does use other cues, including your behavior. Everything you do all day is either helping the master circadian clock to synchronize the bodys functions, or its getting in the way. Setting a daily schedule that reinforces your bodys natural rhythm is the most powerful health habit you can adopt. Its not just the human body that tries to set this daily rhythm. All of nature follows this same diurnal pattern. De Mairans plants were opening their leaves in anticipation of light, even though the light never came to them. Their cells kept trying to keep the daily rhythm. Many types of cells are tasked with doing one set of things in the daytime and another at night. This is true for mammals, for plants, and even for the smallest single-cell bacteria. In the past thirty years, genetic research and microbiology have transformed the study of these natural rhythms. Scientists have been working to discover clock genes inside of cells and how they work at the neurological and molecular level in all types of organisms.

Knowing that cells operate differently at different times in a twenty-four- hour cycle has implications on many different fields. The study of the

circadian rhythm and chronobiology could change many types of medical therapies. For example, if you take a short-acting statin to control your cholesterol levels, your doctor is probably going to tell you to take it at night. Why? Because chronopharmacologists know that that is when the liver produces cholesterol. Researchers are searching for the limit of the

ways in which circadian rhythms rule biological systems in all living things, but they havent found it yet. One researcher noted that it should be assumed that every system in the body works on a circadian rhythm until proven otherwise.

Ayurveda and Chronobiology

Although these findings in chronobiology-based research are still new, they actually reinforce what Ive been practicing in Ayurvedic medicine for decades. Ayurveda is a natural healing tradition that has been practiced in India for about five thousand years. Long before de Mairan wondered about his plants and their strange behavior, Ayurvedic doctors were cautioning patients about the daily cycle of the body and its many systems. Ayurveda separates the day into segments that describe the bodys energies and systems as active or dormant. It teaches that you must have a healthy schedule in order to thrive. In fact, Ayurveda stresses that all of your behaviors, including diet, rest, and exercise, must work together with your master internal clock to keep the body functioning well. It also teaches how to achieve a mind-body connection so that you can stay in touch with what your body needs throughout the day. In fact, Ayurveda is sometimes called the original lifestyle medicine. Literally translating to the science of life, it is the precursor to all of the other healing traditions, including traditional Chinese medicine. As Buddhism spread throughout Asia, its scholars brought Ayurvedic knowledge with them. In traditional Chinese medicine, practitioners teach that balance is essential, that the flow of chi through the body facilitates healing, and that the taste of your food is part of its healing and balancing effect. These ideas were influenced by Ayurveda. Even the Greeks read the Ayurvedic texts, and gleaned some of the wisdom to inform their own ideas about how the body works. Prana, the Sanskrit word for the breath of life, became pneuma to the Greeks. Agni, the heat of metabolism and digestion, became ignis. And, somehow, the three doshas, or prevailing energies, became three of the four humors or metabolic agentsphlegm, cholera, melancholy. In early Ayurvedic texts, one scholar concluded that blood was a fourth dosha, and the Greeks, apparently, agreed, although later Ayurvedic scholars reverted to three doshas. The Greeks believed that these humors, or

tendencies, needed to be balanced, and that a disruption or overabundance of one of these humors was the cause of many diseases, ideas borrowed from Ayurveda. But few other natural healing traditions explore the effect of natural light on the body. Here Ayurveda stands alone in explaining that the bodys systems operate on a daily cycle. It describes a daily routine, a nightly routine, and a seasonal routine to sync your body with the circadian clock. The term chronobiology may be relatively new to Western medicine, but it is an essential part of the Ayurvedic tradition. The texts describe how our bodie are constantly interacting with sunlight and the changing seasons. They talk about how to synchronize your daily routine with this changing natural light. It may be the only medical tradition that talks about how to arrange your daily routine to achieve optimum health throughout the seasons and the decades of your life. Further, its one of the only traditions to talk about body type and how this manifests in certain health problems. This is significant because so much diet and health advice assumes that everybody is more or less the same in their need for sleep, exercise, and food. If you look around a room, you can see that your body is not like everyone elses. In Ayurveda, there is no concept of a single diet or exercise routine that can help every person. While everyone needs to understand how to set a good schedule, not everyone needs exactly the same diet or exercise routine within that schedule to get the best results. In this book, Ill describe why you need good sleep and outline all of sleeps surprising benefits, while in the next chapter, Ill help you identify and solve your particular challenges with sleep. Ill do the same with diet and exercise. If you have one body type, you may struggle to lose weight, but never experience insomnia. Someone with a different body type may never have worried about being overweight, and yet headaches and insomnia are a kind of curse. But there are answers to all of these concerns. So, if youve tried exercise, and you couldnt stick with it, you can find out why and discover how to solve this problem. If youve tried diets and they didnt work, its probably because you didnt find the right diet for you. In Ayurveda we try to balance the whole body and we look at the individual and solve the problems exacerbated by body type. In this way, you can set a schedule that will support your bodys central rhythm, but you will also be able to fine-tune your schedule so that dieting, sleeping, and getting fit will become effortless.

But first, I want to tell you how to stop getting in the way of your circadian rhythm. By making the bodys clock work for you, youll reap

Question: 1- What were your initial thoughts when you read the title of the first chapter Its not you, its your schedule? What do you think this title implies? What kind of effects can your schedule have on your body and mind? Discuss (120-150 words)

2.What is circadian rhythm? (Define in your own words). How is the circadian rhythm disrupted due to the modern daily habits that people have? Were plants the initial source revealing the presence of such rhythm? (180-220 words)

enormous health benefits right away.