How and Why Do We Wake Up?

Everybody has strange experiences with sleep. Sometimes we want to sleep very much and we just cant seem to. We stay awake or wake up early, and sometimes we feel we could sleep for hours and hours more when the alarm clock goes off. What wakes us up is something that scientists still can’t explain fully. 

There are two theories about it, and lets take a look at both of them. One theory says that sleep and fatigue are pretty much the same. The nerve cells become tired because their reserve of energy is used up faster than it can be replenished. Nerve cells can also become tired because waste materials accumulate faster than they can be eliminated. When we go about thinking and seeing and feeling and carrying on mental activities of all sorts, we use up energy. So the brain and other nerve center need a rest. Sleep clears away our tiredness, and when we wake up we are rested and able to function again.

Some scientists believe that what really happens when we fall asleep is that one particular nervous center called the vasoconstrictor center becomes tired. This causes the blood vessels to cut off a certain supply of blood, and we go to sleep. When the center has its blood supply restored to normal we wake up. The other theory about sleep and waking up is quite different. According to this theory, we have a “wakefulness center” in the lower portion of the brain. Our mental activities and emotions during daily living stimulate the center. Now, if we cant shut off messages from the brain to this center we remain awake. When we finally do it, by sending no more messages we go to sleep.

Then suppose we get hungry while we’re asleep or feel cold or damp or experience some emotion such as fear. The wakefulness center is stimulated again and we wake up. But don’t forget that every adult person needs a significant amount of sleep. It depends on your age, your body, your work, and even your sleep habits. An adult really needs only enough sleep so that when they wake up they feel rested and well and can carry on their work during the day.