In making "Inside the Teenage Brain," we seemed to hit a nerve -- a parental one -- when we began looking into the world of teenagers and how they sleep. The patterns that young teens seemed to be experiencing -- an inability to go to sleep at night, followed by profound drowsiness on waking -- seemed so pervasive that it should come as no a surprise that what parents were seeing at home had already been corroborated in university sleep labs at Stanford and Brown.
Reseachers had always believed that sleep was governed by what was called the sleep-wake homeostasis, that is: "All other things being equal, ... the longer one is awake, the greater the pressure for sleep to occur. ... This process accounts for the increased need for sleep after staying awake all night." [1] It seemed perfectly reasonable that people would want to sleep when they were very tired. But it didn't account for a number of patterns that were obvious outside the lab: jet travellers woke up at 2 a.m. despite being exhausted after flying from Boston to London, teenagers had trouble falling asleep though they also seemed to be very tired, older people often woke up very early in the morning.
The Biological Clock
What researchers discovered is an internal biological clock, a clock that sometimes acts against the sleep-wake cycle by keeping us alert when we should be feeling tired. Sleep researchers Mary Carskadon, now at Brown University, and Bill Dement at Stanford had seen this biological clock in action when they tested a group of 10-12 year olds at Stanford. Dement, who pioneered sleep research at Stanford, wrote about these experiments: "After centuries of assuming the longer we are awake, the sleepier we will become and the more we will tend to fall asleep, we were confronted by the surprising result that after 12 hours of being awake, the subjects were less sleepy than they had been earlier in the same day, and at the 10 o'clock test, after more than 14 hours of wakefulness had elapsed ...they were even less sleepy." [2]
