He says it’s not as simple as persuading teenagers to go to bed earlier. “The body’s natural rhythm is controlled by a particular kind of light,” says Kelley. “The eye doesn’t just contain rods and cones; it contains cells that then report to the suprachiasmatic nuclei in the hypothalamus.” This part of the brain controls our circadian rhythms over a 24-hour cycle. It’s like saying: ‘Why can’t you control your heartbeat?’”
What does Kelley say is critical to people’s sleep rhythms?
Certain types of light Going to bed earlier Heart rate Physical exercise