sleep

I included this because I feel that a lot of people I know are not getting enough sleep... especially the JC students... Heh, I'm so glad I've left TJC!!
Nonetheless, I hope that by reading this article, I hope that you will learn more about the negative effects of not sleeping enough... And I did not write this myself! It was taken from an article "Sleepless in Stanford".

How much sleep do we need? What is sleep debt?
Each of us has a specific daily sleep requirement. The average sleep requirement for college students is well over 8 hours and the majority of students would fall within the range of this value plus or minus one hour. If this amount is not obtained, a sleep debt is created. All lost sleep accumulates progressively as a larger and larger sleep indebtedness. Futhermore, your sleep debt does not go away or spontaneously decrease. The only way to reduce your individual sleep debt is by obtaining extra sleep over and above your daily requirement.
The powerful brain mechanism that regulates the daily amount of sleep is called the sleep homeostat. By increasing the tendency to fall asleep progressively in direct proportion to the increasing size of the sleep debt, this homeostatic process ensures that most people will get the amount of sleep they need, or close to it. The elevated sleep tendency together with the associated drowsiness and an intense desire for sleep would ordinarily prevent most people from becoming dangerously sleep deprived because they would go to bed early or sleep late when such excessive daytime sleepiness occurred.
However in our society we are prone to ignore or resist nature's signal that we need more sleep, and we often resist far too long. At this point, we cannot resist falling asleep. Depending on when and where this happens, falling asleep can be tragic, or merely inconvenient. As far as is currently known, nothing can change an individual's fundamental daily sleep requirement.

What causes us to feel sleepy?
To repeat, the size of your sleep debt determines the strength of the tendency or ability to fall asleep. If your sleep debt is zero, sleep is impossible. If your sleep debt is very low, only a small amount of stimulation is required to keep you awake. If your sleep debt is very large, no amount of stimulation can keep you awake.
Think of your sleep debt as a very heavy load. You are carrying with the help of two companions. Together, the three of you can hold it up. One of your companions is pretty strong. This companion is your biological clock. The other companion is not quite so strong and represents transient external stimulation, eg noise, light, excitement, anger, pain and so on. If one of your companions drops out, you and the other may be able to manage. If both companions drop out and you are left alone, you absolutely cannot hold up the heavy sleep debt and you are crushed. In other words, you cannot stay awake no matter how hard you try. Even without external stimulation, it is usually easy to stay awake and alert if your stronger companion, the biological clock, is helping you.
With the above image in mind, it should be clear that the things we usually assume cause us to become drowsy or to fall asleep actually do not cause us to become drowsy or to fall asleep. Their true role is to unmask any tendency to fall asleep that is present already. If you believe that boredom, a warm room, or a heavy meal causes sleep, you are completely wrong! If boredom, a warm room, or anything else seems to cause you to feel drowsy, you have a sleep debt and you need to be stimulated in order to stay awake. If you frequently feel sleep or drowsy in any dull or sedentary situation, you almost certainly have a very large sleep debt. A large sleep debt makes us vulnerable to apathy, inattention and unintended sleep episodes. Errors, accidents, injuries, deaths and catastrophes can be the result, not to mention poor grades.

What is the biological clock? What does it do for us?
The biological clock is a term applied to the brain process which causes us to have 24 hour fluctuations in body temperature, hormone secretion and a host of other bodily activities. Its most important function is to foster the daily cycle of sleep and wakefulness. The major role of the biological clock in the regulation of sleep and wakefulness is to provide an internal and very powerful wake up signal to the rest of the brain.
This powerful signal is called clock - dependent alerting, and when present, it powerfully opposes the tendency to fall asleep. In the absence of any other stimulation, the process of clock - dependent alerting alone can usually keep us wide awake throughout the entire day. This may not be true if we are carring a fairly large sleep debt. In ordinary circumstances, clock - dependent alerting is always synchronized with the daytime hours. However, if we travel rapidly to other time zones, it may occur during the sleeping hours and we experience "jet lag".

Drowsiness is red alert!
I sincerely hope that sleep deprived students will take the following advice very seriously. Drowsiness is red alert! Drowsiness is the last step before falling asleep, not the first. Drowsiness may mean you are seconds from a disaster. If everyone responded as if it were an emergency when they became aware of feeling drowsy, an enormous amount of human suffering and catastrophic events would be avoided.