Sleep Clock

There is an underlying mechanism, called the sleep clock, which consists of a number of variables in your body that tell it when to feel tired, and when to feel awake. It also controls how deep you sleep, and how long you sleep.

Circadian rhythm

The first, and most important part of your sleep clock is your body temperature rhythm. It’s also known as a circadian rhythm.

Contrary to what most of us are taught in grade 5 science class, our body temperature doesn't stay at a constant 98.6º Fahrenheit (37º Celsius). Our body temperature actually has a specific rhythm to it. It rises and drops as the hours of the day progress. The difference in body temperature is about 3º Fahrenheit (2º Celsius). This periodic rise and drop in body temperature tells our mind when to feel tired and when to feel more awake. As body temperature rises, we tend to feel more awake and our brain waves are usually higher. As body temperature drops, we tend to feel more lethargic, tired, and lazy - this is a big cue for our minds to lower brain waves and enter Stage 1 sleep.

There is a slight “drop” of body temperature during the mid afternoon. This is a usual mid-afternoon body temperature slump. You may have noticed, at some point in your life, that you usually feel an urge to sleep or take a nap during the afternoon. This is completely natural, and sometimes the pressure to sleep during the afternoon is as strong as the pressure at night! (Although most of us chose a drug of choice such as caffeine to combat this body slump).

Because of the demands our society puts on us, such as work, children, and social life, most of us can't sleep at this time. As we'll explore later on, nature actually intended for us to have a nap at this time - we'll talk about the science of naps in detail.

Generally, body temperature begins to rise in the early morning hours, drops sometime during the afternoon, then begins to rise until the early hours of the evening. It's at this time that we have “peak performance” body temperature, most people are most active during the early evening hours, this is where body temperature is the highest. Afterwards, body temperature drops and reaches its lowest point at around 4 am.

If your body temperature rhythm is too flat (doesn't rise or drop low enough), or if it's messed up in any other way, chances are you will experience sleep difficulties. It will be difficult for you to sleep deeply.

It's because of the body temperature rhythm that most of us feel sleepy, at precisely the same time every night. It's also why some people can wake up without an alarm clock at precisely the same time every morning. Usually, your body temperature rhythm will follow the same pattern regardless of when you fall asleep. For instance if you've been waking up at 7 AM all your life, this means your body temperature begins to rise at this time. It won't matter if you fall asleep at 11 PM, 12 AM, or 1 AM, your body temperature will rise at 7 AM, and you will feel sleepy at the same time you always did the next day. Unless you take the proper actions to optimize your body temperature, it will usually return to the same pattern.

This is the primary reason why jet lag happens. When you travel really quickly across several time zones, your body may be in a different time zone, but your temperature rhythm is still following the pattern it did before! So if you normally live in Florida, and you take a flight to California; if it's 8 PM in California, your body will still think it's 11 PM, based on your temperature rhythm. As you see, your temperature rhythm really acts as an internal “clock”. Your body temperature rhythm can adjust to a new time zone, or a new sleeping pattern, and this may take from a few days to up to several weeks! This is why trans-continental jet lag is so severe for some people.

Your body temperature rhythm is perhaps the most important concept to grasp about your inner sleep clock. It has a huge impact on how you sleep, and how you function during the day. So what affects your body temperature rhythm? And how could someone possibly “damage” their body temperature rhythm?

SNORING

Long the material for jokes, snoring is generally accepted as common and annoying in adults but as nothing to worry about. However, snoring is no laughing matter. Frequent, loud snoring is often a sign of sleep apnea and may increase your risk of developing cardiovascular disease and diabetes, as well as lead to daytime sleepiness and impaired performance.

Snoring is caused by a narrowing or partial blockage of your airways at the back of the mouth and upper throat. This obstruction results in increased air turbulence when breathing in, causing the soft tissues in your throat to vibrate. The end result is a noisy snore that can disrupt the sleep of your bed partner. This narrowing of the airways is typically caused by the soft palate, tongue, and throat relaxing while you sleep, but allergies or sinus problems can also contribute to a narrowing of the airways, as can being overweight and having extra soft tissue around your upper airways.

The larger the tissues in your soft palate, the more likely you are to snore while sleeping. Alcohol or sedatives taken shortly before sleep also promote snoring. These drugs cause greater relaxation of the tissues in your throat and mouth. Surveys reveal that about one-half of all adults snore, and 50 percent of these adults do so loudly and frequently. African Americans, Asians, and Hispanics are more likely to snore loudly and frequently compared to Caucasians, and snoring

problems increase with age.

Not everyone who snores has sleep apnea, but people who have sleep apnea typically do snore loudly and frequently. Sleep apnea is a serious sleep disorder, and its hallmark is loud, frequent snoring linked to intermittent brief pauses in breathing while sleeping. Even if you don’t experience these breathing pauses, snoring can still be a problem for you as well as for your bed partner. The increased breathing effort associated with snoring can impair your sleep quality and lead to many of the same health consequences as sleep apnea.

One study found that older adults who did not have sleep apnea, but who snored 6–7 nights a week, were more than twice as likely to report being excessively sleepy during the day than those who never snored. The more people snored, the more daytime fatigue they reported. That sleepiness may help explain why snorers are more likely to be in car crashes than people who do not snore. Loud snoring can also disrupt the sleep of bed partners and strain marital relations, especially if snoring causes the spouses to sleep in separate bedrooms.

Snoring also increases the risk of developing diabetes and heart disease. One study found that women who snored regularly were twice as likely as those who did not snore to develop diabetes, even if they were not overweight—another risk factor for diabetes. Other studies suggest persistent snoring may raise the lifetime risk of developing high blood pressure, heart failure, and stroke.

About one-third of all pregnant women begin snoring for the first time during their second trimester. If you are snoring while pregnant, let your doctor know. Snoring in pregnancy can be associated with high blood pressure and can have a negative effect on your baby’s growth and development. Your doctor will routinely keep a close eye on your blood pressure throughout your pregnancy and can let you know if any additional evaluations for the snoring might be useful. In most cases, the snoring and any related high blood pressure will subside shortly after delivery.

Snoring can also be a problem in children. As many as 10–15 percent of young children, who typically have enlarged adenoids and tonsils, snore on a regular basis. Several studies show that children who snore (with or without sleep apnea) are more likely than those who do not snore to score lower on tests that measure intelligence, memory, and ability to maintain attention. These children also have more problematic behavior, including hyperactivity. The end result is that children who snore do not perform in school as well as those who do not snore. Strikingly, snoring was linked to a greater drop in IQ than that seen in children who had elevated levels of lead in their blood. Although the behavior of children improves after they stop snoring, studies suggest they may continue to get poorer grades in school, perhaps because of lasting effects on the brain linked to the snoring. You should have your child evaluated by your doctor if the child snores loudly and frequently—three to four times a week— especially if brief pauses in breathing while asleep are noted and if there are signs of hyperactivity or daytime sleepiness, inadequate school achievement, or slower than expected development.

Surgery to remove the adenoids and tonsils of children often can cure their snoring and any associated sleep apnea. Such surgery has been linked to a reduction in hyperactivity and improved ability to pay attention, even in children who showed no signs of sleep apnea before surgery.

Snoring in older children and adults may be relieved by less invasive measures, however. These measures include losing weight, refraining from tobacco, sleeping on the side rather than on the back, or elevating the head while sleeping. Treating chronic congestion and refraining from alcohol or sedatives before sleeping can also stop snoring. In some adults, snoring can be relieved by dental appliances that re-position the soft tissues in the mouth. Although numerous over-the-counter nasal strips and sprays claim to relieve snoring, no scientific evidence supports those claims.

So why is it that we can sometimes remember our dreams?

Well, if you think about it, most of us don't remember our dreams at all, we only remember some fragments of them for the first 10 minutes when we wake up, then we completely forget about them, and this process continues every single morning.

The reason for this is simple:

When you wake up, you are still partially in-tune with your subconscious mind. You know that feeling of disorientation and slowness when you wake up?

Your conscious mind is slowly “booting up”, like a computer. During this time you have a brief shadow memory window. During this time you can access some of your shadow memory; it's usually at this time that fragments of our dreams still float around our mind aimlessly. As we get up, take a shower and eat breakfast it seems that these memories quickly “deteriorate” and fly out of our minds forever. What's actually happening is your conscious mind is gaining full awareness, and you lose the connection with your subconscious memory.

Because our conscious mind takes over when we wake up, our mind labels the brief half-real fragments of shadow memory as “not important”. When we reflect on them in the 10 minutes after waking up it only seems like our dream(s) may have been a few minutes long.

Tips for Getting a Good Night’s Sleep

·         Stick to a sleep schedule. Go to bed and wake up the same time each day. As creatures of habit, people have a hard time adjusting to altered sleep patterns. Sleeping later n weekends won’t fully make up for the lack of sleep during the week and will make it harder to wake up early on Monday morning.

·         Exercise is great but not too late in the day. Try to exercise at least 30 minutes on most days but not later than 5 or 6 hours before your bedtime.

·         Avoid caffeine and nicotine. Coffee, colas, certain teas, and chocolate contain the stimulant caffeine, and its effects can take as long as 8 hours to wear off fully. Therefore, a cup of coffee in the late afternoon can make it hard for you to fall asleep at night. Nicotine is also a stimulant, often causing smokers to sleep only very lightly. In addition, smokers often wake up too early in the morning because of nicotine withdrawal.

·         Avoid alcoholic drinks before bed. You may think having an alcoholic “nightcap” will help you sleep, but alcohol robs you of deep sleep and REM sleep, keeping you in the lighter stages of sleep. You also tend to wake up in the middle of the night when the effects of the alcohol have worn off.

·         Avoid large meals and beverages late at night. A light snack is okay, but a large meal can cause indigestion that interferes with sleep. Drinking too many fluids at night can cause frequent awakenings to urinate.

·         If possible, avoid medicines that delay or disrupt your sleep. Some commonly prescribed heart, blood pressure, or asthma medications, as well as some over-the-counter and herbal remedies for coughs, colds, or allergies, can disrupt sleep patterns. If you have trouble sleeping, talk to your doctor or pharmacist to see if any drugs you’re taking might be contributing to your insomnia.

·         Don’t take naps after 3 p.m. Naps can help make up for lost sleep, but late afternoon naps can make it harder to fall asleep at night.

·         Relax before bed. Don’t overschedule your day so that no time is left for unwinding. A relaxing activity, such as reading or listening to music, should be part of your bedtime ritual.

·         Take a hot bath before bed. The drop in body temperature after getting out of the bath may help you feel sleepy, and the bath can help you relax and slow down so you’re more ready to sleep.

·         Have a good sleeping environment. Get rid of anything that might distract you from sleep, such as noises, bright lights, an uncomfortable bed, or warm temperatures. You sleep better if the temperature in your bedroom is kept on the cool side. A TV or computer in the bedroom can be a distraction and deprive you of needed sleep. Having a comfortable mattress and pillow can help promote a good night’s sleep.

·         Have the right sunlight exposure. Daylight is key to regulating daily sleep patterns. Try to get outside in natural sunlight for at least 30 minutes each day. If possible, wake up with the sun or use very bright lights in the morning. Sleep experts recommend that, if you have problems falling asleep, you should get an hour of exposure to morning sunlight.

·         Don’t lie in bed awake. If you find yourself still awake after staying in bed for more than 20 minutes, get up and do some relaxing activity until you feel sleepy. The anxiety of not being able to sleep can make it harder to fall asleep.

·  See a doctor if you continue to have trouble sleeping. If you consistently find yourself feeling tired or not well rested during the day despite spending enough time in bed at night, you may have a sleep disorder. Your family doctor or a sleep specialist should be able to help you.

Top 10 Sleep Myths

Myth 1: Sleep is a time when your body and brain shut down for rest and relaxation.

No evidence shows that any major organ (including the brain) or regulatory system in the body shuts down during sleep. Some physiological processes actually become more active while you sleep. For example, secretion of certain hormones is boosted, and activity of the pathways in the brain needed for learning and memory is heightened.

Myth 2: Getting just 1 hour less sleep per night than needed will not have any effect on your daytime functioning.

This lack of sleep may not make you noticeably sleepy during the day. But even slightly less sleep can affect your ability to think properly and respond quickly, and it can compromise your cardiovascular health and energy balance as well as the ability to fight infections, particularly if lack of sleep continues. If you consistently do not get enough sleep, eventually a sleep debt builds up that will make you excessively tired during the day.

Myth 3: Your body adjusts quickly to different sleep schedules.

Your biological clock makes you most alert during the daytime and most drowsy at night. Thus, even if you work the night shift, you will naturally feel sleepy when nighttime comes. Most people can reset their biological clock, but only by appropriately timed cues—and even then, by 1–2 hours per day at best.

Consequently, it can take more than a week to adjust to a dramatically altered sleep/wake cycle, such as you encounter when traveling across several time zones or switching from working the day shift to the night shift.

Myth 4: People need less sleep as they get older.

Older people don’t need less sleep, but they often get less sleep or find their sleep less refreshing. That’s because as people age, they spend less time in the deep, restful stages of sleep and are more easily awakened. Older people are also more likely to have insomnia or other medical conditions that disrupt their sleep.

Myth 5: Extra sleep at night can cure you of problems with excessive daytime fatigue.

Not only is the quantity of sleep important but also the quality of sleep. Some people sleep 8 or 9 hours a night but don’t feel well rested when they wake up because the quality of their sleep is poor. A number of sleep disorders and other medical conditions affect the quality of sleep. Sleeping more won’t alleviate the daytime sleepiness these disorders or conditions cause. However, many of these disorders or conditions can be treated effectively with changes in behavior or with medical therapies.

Myth 6: You can make up for lost sleep during the week by sleeping more on the weekends.

Although this sleeping pattern will help relieve part of a sleep debt, it will not completely make up for the lack of sleep. This pattern also will not make up for impaired performance during the week because of not sleeping enough. Furthermore, sleeping later on the weekends can affect your biological clock so that

it is much harder to go to sleep at the right time on Sunday nights and get up early on Monday mornings.

Myth 7: Naps are a waste of time.

Although naps do not substitute for a good night’s sleep, they can be restorative and help counter some of the impaired performance that results from not getting enough sleep at night.

Naps can actually help you learn how to do certain tasks quicker. But avoid taking naps later than 3 p.m., as late naps can interfere with your ability to fall asleep at night. Also, limit your naps to no longer than 1 hour because longer naps will make it harder to wake up and get back in the swing of things. If you take frequent naps during the day, you may have a sleep disorder that should be treated.

Myth 8: Snoring is a normal part of sleep.

Snoring during sleep is common, particularly as a person gets older. Evidence is growing that snoring on a regular basis can make you sleepy during the day and more susceptible to diabetes and heart disease. In addition, some studies link frequent snoring to problem behavior and poorer school achievement in children. Loud, frequent snoring can also be a sign of sleep apnea, a serious sleep disorder that should be treated.

Myth 9: Children who don’t get enough sleep at night will show signs of sleepiness during the day.

Unlike adults, children who don’t get enough sleep at night typically become more active than normal during the day. They also show difficulty paying attention and behaving properly. Consequently, they may be misdiagnosed as having attention deficit hyperactivity.

Myth 10: The main cause of insomnia is worry.

Although worry or stress can cause a short bout of insomnia, a persistent inability to fall asleep or stay asleep at night can be caused by a number of other factors. Certain medications and sleep disorders can keep you up at night. Other common causes of insomnia are depression, anxiety disorders, and asthma, arthritis, or other medical conditions with symptoms that become more troublesome at night. Some people who have chronic insomnia also appear to be more revved up than normal, so it is harder for them to fall asleep.

Sleeping heart

What sleep does for your heart...

Sleep gives your heart and vascular system a much-needed rest. During non-REM (Rapid Eye Movement) sleep, your heart rate and blood pressure progressively slow as you enter deeper sleep. During REM sleep, your heart rate and blood pressure have boosted spikes of activity. Overall, however, sleep reduces your heart rate and blood pressure by about 10 percent.

If you don’t get enough sleep, this nightly dip in blood pressure, which appears to be important for good cardiovascular health, may not occur. According to several studies, if your blood pressure does not dip during sleep, you are more likely to experience strokes, chest pain known as angina, an irregular heartbeat, and heart attacks. You are also more likely to develop congestive heart failure, a condition in which fluid builds up in the body because the heart is not pumping sufficiently.

Failure to experience the normal dip in blood pressure during sleep can be related to insufficient sleep time, an untreated sleep disorder, or other factors. African Americans, for example, tend not to have as much of a dip in blood pressure during sleep. This difference may help to explain why they are more likely than Caucasians to have serious cardiovascular disease.

A lack of sleep also puts your body under stress and may trigger the release of more adrenaline, cortisol, and other stress hormones during the day. These hormones contribute to your blood pressure not dipping during sleep, thereby increasing the risk for heart disease. Inadequate sleep may also negatively affect your heart and vascular system by the increased production of certain proteins thought to play a role in heart disease. For example, some studies find that people who chronically do not get enough sleep have higher blood levels of C-reactive protein. Higher levels of this protein may suggest a greater risk of developing hardening of the arteries (atherosclerosis).