Are you weepy?
Are you forgetful?
Can't you shake that cold?
Are you clumsier than usual?
Have you lost that loving feeling?
If the answer to some of the questions above is 'yes', you may be short of sleep. Read this short Huffington Post article and the accompanying slideshow to find out more about the topic.
You can also watch this video where Dr. Rizan Hajal explains the basics of sleep.
Self-study activity: Watch the video and answer these questions:
1 Does everybody need an eight-hour sleep?
2 What does 20% refer to at the beginning of the interview?
3 Does our brain go into a mini-coma when we sleep?
4 How long is a sleep cycle approximately?
5 Is the REM sleep the deepest cycle of sleep?
6 What happens if we don't get the REM sleep?
7 How long do we spend in the lighter stage of sleep?
You can check the answers by reading the transcript below.
Raena Morgan: Dr. Hajal, basic question. How much sleep do we need to get? The typical eight hours, is that?
Dr. Rizan Hajal: I don't have a clear scientific answer to tell you. It's still true, what your grandma said, perhaps that you need somewhere between seven and nine hours and majority of the people, almost 80% of the people, require something around that, but which tells you that almost 20% of the people can sleep something different. We're talking about normal sleep, not those who have trouble falling asleep or who cannot fall asleep. We're talking about normal sleep, which means they wake up feeling rested and comfortable. Some people need six hours. Some people need 11 hours, so we don't really know.
Raena Morgan: What is a sleep cycle?
Dr. Rizan Hajal: A sleep cycle is, it's very important when you're sleeping to know that it is not one stage of sleep, so it's not like our bodies go into a mini-coma at night, through the night, and then you wake up. To the contrary, actually your brain is working on sleep and so it has to be a sequence of events that you go through. We know there are three stages of regular sleep and one stage of REM sleep, rapid eye movement sleep. And then, of course, there's the wake and those stages don't come just randomly at night. You go from one cycle to another and we find that every 90 minutes is almost a cycle and then you keep repeating that and the more cycles you will get, the more restful you will feel the next day and they have to come in this sequence so if you have a sleep disorder that gives you maybe the same number of minutes at the end of the night, but not in the same sequence, you will not feel rested the next day. So, they have to come in this sequence. So it has to be orchestrated. The brain is doing a process, an active process, to actually wake up feeling rested the next day.
Raena Morgan: So the REM sleep, that's the deepest cycle of the sleep?
Dr. Rizan Hajal: It's one of the deepest. There is also the slow wave sleep, which is a different kind of deep sleep that its definitely one of the restful sleep that we should get into.
Raena Morgan: So, if you don't get that sleep, then you're not going to be refreshed.
Dr. Rizan Hajal: That's true and many studies would show that they would start eliminating those parts of sleep on volunteers and they will see what the effect of that is. And most of them end up feeling just completely unable to function just sleepy and the difference was not that much, which stage you would block to make your sleep as a true which tells us that we actually need all stages of sleep to actually wake up feeling refreshed.
Raena Morgan: Even a lighter stage?
Dr. Rizan Hajal: The lighter stage is of course, if you spent too much in the lighter stage, then it's not a refreshing stage so we do need a little bit more of the deeper ones. But it's normal for you to spend 20% of your sleep in lighter stage. That's normal, healthy sleep.
Raena Morgan: Thank you Dr. Hajal.
Dr. Rizan Hajal: Thank you.