Certain sections of our brains remain active while we sleep, but our brains and our bodies need rest. Seven to nine hours is recommended. Some people need as few as six hours. Others may need ten. Older people do not need less sleep. We need about the same amount that we did as young adults. What does change is our sleep patterns. 

Have you ever wondered why we sleep?

Adults spend about one third of their time sleeping. For babies and toddlers it’s even more, about half their time. Sleep must be really important since we spend so much time doing it, right? But important how? We all know how badly we feel when we don’t get enough sleep. What exactly does sleep do for us? Surprisingly, with all the research that’s been done, we still don’t really know. We’re not sure why we sleep, or exactly what mechanisms are responsible.

We know that sleep allows us to rest. It gives our muscles a chance to recuperate. We used to think that our brains rested too. Instead what we’ve found using EEG, (electroencephalogram, or brain wave recordings), is that our brains are quite active when we sleep. So what’s going on?

Right after falling asleep there is slow wave EEG activity, named appropriately, slow wave sleep, (SWS). After a short time, sleep enters a second stage. The activity is very fast, and very similar to when we are awake and attentive. Paradoxical, right? So it’s called paradoxical sleep. Because our eyes move rapidly during this sleep stage, it’s also known as Rapid Eye Movement, or REM, sleep. This is when we dream.​

But something else seems to be happening during REM. The brain appears to be reviewing and sorting through all the information it has been exposed to during the day. Some gets stored. The rest is discarded.

During one study, letters were briefly flashed on computer screens. People were taught to identify the letters. Half the study subjects were then allowed to go home to sleep. The others were kept awake all night, and then sent home. Two days later they all returned. By that time they were all well rested. When tested on their ability to read the flashing letters, those who had been able to sleep right after the training did much better than those who did not get to sleep until the next day. It seems that sleeping soon after a learning activity enables you to gain the most from that session.

Remember those all nighters you pulled studying for exams? A waste of time!

It also suggests that those all nighters you pulled studying for exams……waste of time. Tell your kids and grandkids to go to bed. Get a good night’s sleep. Their brains will still be working, committing the important information to memory, and better able to recall it in the morning.​

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