Sleep phase disorders can disrupt day to day activities and enjoyment. I'm Erin White and this is a dailyRx Feature. Whether you tend to be a "night owl" or an "early bird", every person's body has an internal clock that helps regulate when their bodies feel tired and ready for bed and when they're ready to greet the new day. These internal clocks, called circadian rhythms, are partly regulated by melatonin, the hormone that tells the body it's time for sleep, and by sunlight, which resets our internal clocks. People whose circadian rhythms seem to be way off from the typical day-night cycle, might have a sleep disorder. Symptoms of sleep disorders may include not being able to fall asleep until very late and waking up extremely early. Ask your doctor how to improve your sleep schedule. For dailyRx TV, I'm Erin White.