Circadian Rhythm Sleep Disorders are sleep disorders that affect or are affected by your circadian rhythm – what is essentially your body’s internal clock. Among other things, your circadian rhythm tells you when it’s time to go to bed and time to get up. Your sleep and circadian rhythms are very closely connected. In normal, healthy sleepers, their body clock tells them to go to bed sometime between 10pm to 12am each night and wake up 7-9 hours later between 5am – 7am. People suffering from circadian rhythm sleep disorders, however, don’t function on the same sleep schedules – their body clocks are out of whack and that makes it difficult for them to get regular sleep.
Circadian rhythm sleep disorders can be classified into two groups – extrinsic (external) and intrinsic (internal). Extrinsic types of circadian rhythm sleep disorders are when something external causes your sleep problems. These include jet lag and shift work sleep disorder.
Jet lag occurs when travelling across different time zones and the body’s clock thinks it’s a different time than it actually is. And people suffering from Shift Work Sleep Disorder (SWSD) have abnormal working hours and therefore go to bed and wake up either at different hours each day or opposite to when healthy sleepers wake and sleep.
Intrinsic types of circadian rhythm sleep disorders include:
Delayed Sleep Phase Syndrome (DSPS) – going to bed and waking up later than “regular” people
Advanced Sleep Phase Syndrome (ASPS) – having trouble with both remaining awake during evening hours as well as remaining asleep during morning hours.
Non-24-Hour Sleep-Wake Syndrome (Non-24) – going to sleep at least an hour later than the night before, never being able to develop any type of sleep schedule.
Irregular Sleep-Wake Rhythm – sleeping at odd times throughout the day – including naps – but overall sleeping the same amount of time as healthy sleepers.
To combat certain circadian rhythm sleep disorders, some doctors recommend bright light therapy. People undergoing bright light therapy are exposed to bright lights that manipulate the body’s clock, helping them adjust to a new sleep time or a new time zone.
Circadian rhythm sleep disorders are very dangerous as they can lead to accidents in the workplace or while on the road. It is thought that the accidents at Three Mile Island, Chernobyl and the Exxon Valdez oil spill were attributed to night-shift workers’ fatigue. Anther circadian rhythm sleep disorder “cure” includes the use of melatonin supplements. Since melatonin is a naturally produced hormone which increases after dark and makes us feel sleepy, taking these supplements at optimal times have proven to be effective in aiding people suffering from circadian rhythm sleep disorders.