About ten percent of the population is diagnosed with chronic insomnia. They have difficulty falling asleep, wake up in the middle of the night and have difficulty falling asleep again. Many of them are in a state called hyperarousal, which means that the brain is not as down-regulated as it should be in deep sleep. This means that you can both sleep and be aware at the same time.
Play the video "Why can I not sleep" above and hear one of the world's leading sleep researchers explain.
More about sleep in Vetenskapens Värld on Monday 17 August 20.00 in SVT2 or on SVTplay from Sunday 16 August.