By exposing sleep-deprived people to specially designed full-spectrum lights (10,000 lux fluorescent bulbs) for 30 minutes in the early morning, scientists have helped them get to sleep earlier and stay asleep longer. One theory is that regular exposure to such light in the morning triggers a more advantageous nighttime release of melatonin, the hormone that keeps your body clock on a regular schedule, ensuring that you feel sleepy in the evening and stay asleep through the night.
Light therapy can work wonders for people who find it difficult to fall asleep before midnight and are sluggish in the morning. For serious insomnia, it's best to work with a sleep specialist to devise a treatment program, which usually requires that you commit to waking up earlier each morning. But if you're suffering, it's worth a try.