Circadian Rhythm Sleep Disorders

Image of woman sleeping

Setting Your Sleep Schedule

Circadian rhythms are the physical and mental changes that occur throughout the course of the day and affect whether you feel awake or sleepy. They are regulated by chemicals released in your brain in response to a stimulus, such as light. For example, you wake up in the morning because of chemicals that are released as your brain reacts to sunlight. The opposite occurs with a reduction in light, so in the evening your brain responds by making you feel drowsy.

Disrupting your circadian rhythm can lead to problems with sleep. Two examples are jet lag, which can happen when you travel across time zones, and shift work sleep disorder, which affects people who work at night and sleep during the day. These disorders occur because your natural sleep-wake cycles are interrupted.

Delayed sleep phase syndrome (DSPS) is the most common type of circadian sleep disorder. People with DSPS tend to stay up late at night and wake up late in the day. Delayed sleep phase syndrome can interfere with work and school because the sufferer is unable to fall asleep at regular "normal" sleep times.

Your sleep schedule doesn't have to be determined by family, work and social commitments. You can figure out optimal bed and wake times that afford the best, most restful sleep.

  • Figure out what time you need to wake up each morning, and count backwards to figure out when you should head to bed. Seven-to-nine hours of sleep is optimal.
  • Consider your circadian rhythm. Figure out whether you tend to be most alert in the morning or at night, so you can adjust your sleep schedule to your body's needs.
  • An ideal bedtime for most people is between 8 p.m. and 12 a.m. Adjust your bedtime based on whether you're waking up before your alarm in the morning, or struggling to fall asleep within 20 minutes.
  • Stick to the same sleep schedule on weekends.