Interesting Facts About Sleep
Sleep More, Weigh Less
As our bodies sleep many events take place. Our immune system for instance kicks in and helps us to make repairs, rebuild muscle tissue, and fights off illnesses. When we initially fall asleep our bodies take some time to ease down into gradually deeper and deeper levels of sleep. In doing so our heart rate decreases, our breathing slows down, and our body temperature decreases.
When we begin to wake up and come out of that deep state of sleep, the reverse happens. Our heart rate, blood pressure, body temperature, and rate of breathing begin to increase. In order to facilitate these events our bodies release certain hormones and other substances. Cortisol for example is a stress hormone that helps to provide us with a greater sense of alertness. Increased levels of cortisol help us to wake up in the morning.
Leptin and ghrelin levels also increase. Leptin is created in fat cells and serves to tell the brain how much energy the body has available to perform everyday tasks. It makes sense that our energy levels would change (would increase) as we wake up. Thus our leptin levels will increase to normal levels when we've had enough sleep and our body is ready to wake up. These levels are lower when you're asleep and don't have (don't need) the same amount of energy.
If you cut your sleep short your leptin levels may be lower than they would otherwise be. When leptin levels are low your brain receives the message that energy levels are low. In order to build up energy levels the brain in turn sends a signal back to your body to get more energy. We get that energy by eating. Thus if you don't get enough sleep your body will tell you that it's hungry in order to gain more energy. This in turn can lead you to overeat and potentially gain weight.
On a side note... because leptin is created in fat cells its levels would also decrease if you began to starve your body. As you starve, you would lose energy, and your body would send hunger signals encouraging you to eat more and thus to regain a healthier weight and healthier energy levels. This is a positive use of leptin. But when we fail to get enough sleep this process that was intended for good can work against us. This also helps to explain why starvation diets don't work.
While higher levels of leptin tell the body that it's satisfied and doesn't need more energy or more food, its counterpart ghrelin works in the opposite direction. When ghrelin levels are high your brain sends signals to your body that you're hungry. Typically ghrelin levels are highest before you eat and lowest after you eat.
In addition to regulating hunger levels, ghrelin also plays a key role in stimulating growth hormones and aids in the process of learning and adapting to change. All three of these things are believed to occur naturally as we sleep. As a result ghrelin levels are higher when we're asleep. Growth hormones are used in part to help the body grow and rebuild muscles. Some researchers have also theorized that sleep and dreams give us an opportunity to learn, to store memories, and to come up with ways to adapt to change and solve problems.
Since ghrelin levels are higher when we sleep (in order to help with physical, emotional, and educational growth) if we cut short the amount of sleep we receive, ghrelin levels may still be high. With levels still high the body will tell you that its hungry, seeking out more food and energy that can be used for growth purposes.
As interesting as this may all sound, it's worth mentioning that getting while getting an appropriate amount of sleep can decrease your appetite, simply sleeping more or intentionally oversleeping will not automatically cause you to lose weight. But getting an appropriate amount of sleep can make it easier to maintain an appropriate weight.
Choosing Later Classes may not be About Laziness
Many high schools and colleges begin very early in the morning. Teachers, counselors, and school administrators can all attest to the fact that many young people do not like these early classes. Whether in high school or college, many students not only feel less alert and less awake during those earliest classes, but many of them even fall asleep in class.
Seeing those same students staying up late on school nights and staying out late the night before an early class, most adults assume that these young people are simply being immature. But studies have suggested that this many not in fact be the case.
Our bodies have an internal clock that helps us to naturally regulate when we should be awake and when we need to get some sleep. Hormones such as melatonin play a role in this. Melatonin specifically is a naturally occurring hormone that increases in the evening when the sun goes down and increases in the morning as the sun rises. Higher levels in the evening make us sleepy, while lower levels in the morning and during the day keep us more alert. In fact some people take melatonin supplements as a sleep aid.
Because melatonin levels correspond to the rising and setting of the sun, we often find ourselves tired earlier in the winter when it gets dark earlier and more energized in the summer when the sun sets later. Similarly this is why people who travel far from the Equator in places like Alaska and Russia for instance, may feel that their sleep cycles are somehow off. It can take time to adjust to having the sun up or down for twenty plus hours a day.
Additionally, most of us know that adults need less sleep than growing children. Infants and newborns need the most sleep, but teenagers and younger children still need plenty of sleep. Teenagers are not being lazy when they sleep longer than adults; they are simply fulfilling a natural and biological need. As puberty reminds us, the bodies of teenagers are still growing. This means that their bodies need more sleep to perform all the tasks that occur during sleep, particularly those that relate to growth.
Aware of this, the brain controls hormones (like melatonin) that regulate our internal clocks so that we get tired when we need more sleep. Just as sleeping infants are responding not to the clock on the wall, but to their own internal clocks by sleeping in excess of 12-14 hours, teenagers too are often simply responding to the natural needs of their bodies. Teenagers typically need about nine hours of sleep a night to be at their best. Five to twelve year olds need closer to ten or eleven hours, while preschoolers often need even more.
Research studies have also shown that the natural timing of sleep patterns in young people tends to be later than it is in adults. To help appreciate this age-based adjustment in the natural timing of when we sleep compare the sleeping preferences of a 30-50 year old adult and those of a retirement age adult. Just as seniors may eat dinner earlier, go to bed earlier, and wake up earlier than 30-50 year old adults, those who are younger will do the reverse.
This means that it's natural for school children, teenagers, and traditionally-aged college students to sleep later into the morning and fall asleep later in the evening. Yet while many adult workplaces do not begin their days until 9:00AM, many schools and colleges begin classes as early as 7:00AM.
It has been recommended that schools show more leniency with their scheduling and assumptions of laziness. Studies have shown that schools who have taken this into consideration and made the adjustments to start their days later have seen a number of positive changes in their students. Some of the benefits include:
Better attendance rates
Greater alertness in class
Better academic performance
Better physical health and athletic abilities
Increased energy levels
Lower dropout rates
Less lateness to class
Decreased levels of student depression
Decreased levels of obesity
Better student nutrition
With this information, parents and school administrators, teachers, counselors, etc. should also try to be more understanding of tired students. While we may not be able to change the policies of a particular school, we can still use this information to benefit and better appreciate our children.
When a student favors taking a class at 10AM instead of 8AM, instead of assuming that he or she is lazy we should consider that they may simply responding to their body. Allowing them to start their day later may also make our young people healthier, smarter, and down the road more competitive in the global marketplace.
The National Sleep Foundation has an article that speaks further about this research finding.
Sleeping in Multiples of 90 Minutes
When our bodies sleep we go through a series of certain stages. During the course of the night we can cycle through these stages as many as seven times. Each sleep cycle lasts approximately 90 minutes and each stage within a sleep cycle serves certain and specific functions. When we sleep a number of naturally beneficial things happen.
In stage four for instance, we enter into one of the deepest levels of sleep and our bodies begin to rejuvenate themselves, to rebuild muscle tissue, and amp up the immune system. This is a very important stage and part of the process of sleep. While we do not fully understand all of the benefits of sleep, we do know that sleep and dreaming are important.
Some theories behind the benefits of dreams include memory improvement, forgetting insignificant events of the day to make room for more important memories, solving problems, and discovering unconscious thoughts and emotions. Regardless of the precise reason or reasons for why we dream, we know that dreaming and sleep overall serves an important role. In fact, if you wake up while in the middle of REM sleep, which is when most dreams occur, and then quickly return to sleep, instead of beginning from the beginning of the sleep cycle with stage one, your body will jump immediately back into the REM sleep that is associated with stage 5 sleep.
With each stage of sleep serving specific and important functions, even if scientists and researchers have yet to identify all of those benefits and functions, we know that obtaining a good night's sleep and an adequate amount of sleep is important. Additionally, given that certain events such as REM sleep do not occur in all stages of sleep, it can also be argued that completing an entire sleep cycle is more important than simply collecting a certain number of hours of sleep each night.
Let's assume for argument's sake that six hours is the minimum amount of sleep required to function the next day. Most people would then agree that six hours of sleep is important and that a person who gets less than six hours will be tired, groggy, less effective, and possibly irritable in the morning.
But thinking in terms of sleep cycles and the fact that they last 90 minutes, if we wanted to sleep beyond six hours with the goal of feeling even more refreshed and receiving still more of the other healthy benefits associated with sleep, we could argue that 7½ hours of sleep would be a good amount. 7½ hours is ninety more minutes than six hours and thus would provide you with one additional complete sleep cycle. Likewise 9 hours of sleep should provide you with two additional complete sleep cycles.
On the contrary, sleeping for 6 hours and 25 minutes, 7 hours and 10 minutes, 8 hours, or 8 hours and 35 minutes would presumably mean ending your sleep in the middle of a sleep cycle and cutting off short one of the beneficial stages of sleep.
While this sounds good in theory and while researchers tends to recommend that adults strive for between six and nine hours of sleep a night, our sleep cycles are not exactly or consistently a precise 90 minutes long. Though they on average tend to last approximately 90 minutes, the exact length of our sleep cycles will vary.
You may then be wondering if we can't rely on 90-minute increments for deciding how long to sleep, what we should do. Well, sometimes our bodies know best and we can simply allow nature to run its course. See the next section on alarm clocks for more information.
What's Wrong With Alarm Clocks?
When we sleep a number of naturally beneficial things happen. While science has not yet uncovered all of the benefits gained from sleep, we do know that an adequate amount of sleep and a good quality sleep are very important. Some of the benefits of sleep include:
Greater mental alertness
Improved physical performance
Better academic performance
Further brain development
Greater cardiovascular health
Lower stress levels
Higher energy levels
Greater mental and emotional flexibility
Decreased likelihood of mental illness
Improved overall health
Greater resistance to illness
Lower risk of depression
Improved ability to solve problems
Again, we know that sleep is important for these reasons and many others. We also know that the lack of sleep can cause us to be irritable, cranky, impatient, less alert, less clear thinking, and less productive during the day. Additionally, researchers have learned that we sleep in certain stages and that many of the benefits of sleep occur in specific stages or at specific points in the course of our being asleep.
For example in stage four our bodies secrete growth hormones, rebuild muscle tissue, and focus on fighting illness. In stage five, we are most likely to dream. Though there may not be a consensus for why we dream, there have been many theories suggested behind the purpose of dreaming and how dreams serve to benefit us.
Also in the fifth stage of sleep we enter into REM sleep. While we may not fully appreciate or understand the reason for this Rapid Eye Movement or the benefits of REM sleep, we do know that our bodies consider it to be important. In fact, if you wake up in the middle of REM sleep and then quickly fall back asleep, instead of beginning from the beginning of the sleep cycle with stage one, your body will jump immediately back into REM sleep.
If left to wake up on our own, our bodies will conclude stage five sleep and move briefly into a transitional state where our bodies come up out of the deep sleep we were in while in REM sleep. At this time our bodies decrease the amount of melatonin and increase the amount of cortisol in our system making us less tired and more alert. Our body knows when we've had enough sleep and it's then that we enter into this final transitory stage after which we naturally wake up.
By using an alarm clock we are interrupting our natural sleep cycle. We're cutting things off in the middle of the process. While we may not know exactly what precise benefits we may be missing out on, we know that if our bodies still want to be asleep and we force them to wake up we're cutting something off. By doing this, we are also likely interrupting the beneficial events that occur during a specific stage of sleep.
Of course, giving your body the sleep that it needs and is asking for is not the same thing as being lazy and sleeping half the day away. We all need to find balance and if we get into a regular routine of going to bed around the same time each day and waking up around the same time each day, our bodies will guide us. They will tell us if we need to add another 30 minutes or another hour. When you finally get the timing right your body will wake up without the use of an alarm clock. Being fully rested and in the habit of abiding by a regular routine, your internal clock will become the only alarm you need.
Morning Erections May Have Nothing to do With Sex
It's a known fact that when men get sexually aroused they develop erections. This is a normal biological occurrence that is necessary for a man to engage in sexual intercourse. However men can also get erections just by thinking about sexual activities, playing out fantasies in their mind, or seemingly randomly when going through puberty.
Most boys and men have at some point in their lives woken up in the morning to find themselves with an erection and a sexual thought or fantasy. The assumption by most is that they were having a sexually based dream which caused the erection. But in reality, we might have the order reversed. Having woken up with an erection the boy or man may draw an immediate mental association to sexual activity, which can in turn lead him to create a sexual fantasy.
We usually assume that cause and effect relationships operate in only one direction, when in reality they often work both ways. When we're happy we smile. But research has shown that the mere act of making ourselves smile can actually increase our feelings of happiness. Go ahead and try it. Can you be angry and smile at the same time?! Another example is the relationship between eating and weight. If you eat more food you're likely to gain weight. But it's also true that if you weigh more than you're likely to eat more food.
So if sexual dreams are not necessarily the cause of morning erections, what then is? The answer may lie in a phenomenon called REM atonia. When we sleep, we dream. Whether we remember them in the morning or not, we have dreams every night. Dreams can be very realistic to the point where our bodies cannot always distinguish between reality and fantasy, between what's real and what's a dream.
Our muscles tense up and essentially become paralyzed when we dream so that we don't act our dreams. Doing so could be dangerous to not only yourself but to anyone else nearby. As the muscles tense up, men frequently develop erections. Think of the penis as just another muscle tensing up.
Another fact to keep in mind is that erections in men do not disappear instantly. It is only as the blood that flows into the penis to create an erection dissipates that the erection will disappear.
If a man or a boy wakes up suddenly because of an alarm clock, a loud relative, or whatever other cause, he may still have the erection that occurred while he was dreaming; an erection caused by REM atonia. While it's certainly possibly that he was having a sexual dream, the mere fact that he has an erection is not alone proof that he was having a sexually based dream. It may simply be that he woke up more quickly than his body would ideally have liked to and the blood has not yet had enough time to leave his penis.
As mentioned earlier once he notices the erection, he may quickly draw an association to and begin to think about sex even without consciously realizing it. This in turn can maintain the erection creating a circular causative effect, meaning that the erection causes sexual thoughts and the sexual thoughts cause the erection to persist which causes still more sexual thoughts.
In older men who may have difficulty developing an erection, it is often suggested that they attempt to have sex in the morning as opposed to at night. This is because doctors and researchers are aware of this phenomenon and of how it can act like a sexual jump-start. Like a car battery, sometimes just getting started is all you need help with.