Chronogiologists study life as a whole. Your days and your nights. Is something predisposing you to insomnia? Maybe not, the cause could be something internal in your neurons, in your sleep center. But generally, an external cause has to be considered. We try to figure out why sleep problems and chronobiological disorders are on the rise. And we come to a very simple conclusion, one that can also be measured, and it's this. Imagine how you would live if you had three different clocks in your brain. Clocks from Tokyo, London, and New York. And your physical body had to combine those time zones. Well that's what we're doing. We have a clock, an internal and a biological clock that's telling you: "Hey, no, I'd rather sleep between two and ten in the morning. That's my biological time slot." We have a second clock, based on artificial light, that we can use to generate the light-dark cycle we want. It's no longer the sun that generates it. But we also have a third clock, a social clock. The social clock is: When can I sleep well, sleep what I need to sleep, if I have to go into work at eight in the morning and I need an hour and a half to go to work? So I have to get up at 6:30. When would I have to go to bed to adhere to this schedule? So when you notice the impossibility of making it all fit, you realize where the problem lies. The problem oftentimes is that your internal and social clocks don't match. And those imbalances are measured in hours. The more hours they're out of phase, the worse you are. For example, if you have a problem with insomnia and we see that it's not a problem due to the three clocks, to inconsistencies with the three clocks, we rule out the chronobiological part and look elsewhere.
What's the purpose of sleep? We know part of its purpose, but not all. Just four years ago, a primordial function of sleep was discovered. Sleep cleans the brain of toxic substances that build up during the day. If you'd get enough sleep, if you don't sleep soundly, those deposits that can later cause Alzheimer's, Parkinson's or cognitive impairment don't get flushed out well and they build up and damage your neurons. So we need to sleep. Even if we don't feel the need in the early stages of life, we have to get enough sleep and sleep soundly.
Sleep has a profound effect on learning and performance. We don't know the figures, but much of the academic failure we experience could be attributed to not enough sleep. It's a very generalized problem. I don't think we realize, as a society, how important this is. We who are involved in teaching see a lot of dazed faces at nine in the morning. And by noon, there's no way to shut them up. So we have a phase delay problem as young people go to bed later and later. And since they have to get up early for school, they're deprived of sleep.
And what does sleep deprivation do to performance? Well, for example, it increases reaction times, the speed at which we become aware of any type of stimulus. What kids often do is they disconnect. They get drowsy and since on top of that, learning tends to be very passive, since they're receiving what someone else is actively explaining, they simply disconnect and think about something else. And that's easy to understand, naturally. The sleep center that determines their biological clock is still at six or seven in the morning. You woke them up halfway through their sleep. And you're taking them to school and passively sitting them down to receive information. What do you expect?