Circadian rhythms: the body's natural time cues
Circadian rhythms influence body temperature, sleep, wakefulness and a variety of hormonal changes. Sunlight and other time cues help us set our circadian cycles so that they are consistent from day to day.
Disorders associated with circadian rhythms
Jet lag and shift work
One of the most common circadian problems is jet lag, which occurs when a person travels across several time zones or during daylight savings time changes. Individuals who work nontraditional hours such as night shift and/or rotating shifts may face similar problems. These Individuals must continually adjust their schedules as their shift changes. Try to allow extra time for adjusting to a long trip or a changing work schedule. Often a short nap during the day is helpful. Occasional use of a short acting sleeping pill may also help. As always check with your physician before taking medications.
Inheriting circadian rhythm problems
People's circadian system can be determined by genetics. Age also appears to impact the natural rhythm and ability to respond to time cues.
Delayed Sleep Phase Syndrome (DSPS)
Individuals with Delayed Sleep Phase Syndrome are not able to fall asleep until late into the night. The problem is most common in young adults and can interfere with employment and school, and may lead to psychological stress.
Advanced Sleep Phase Syndrome (ASPS)
Individuals with Advanced Sleep Phase Syndrome often wake up too early and then aren't able to go back to sleep. Sleepiness usually begins in the early afternoon.
Inability to adjust to a regular sleep schedule
Some individuals have sleep/wake cycles that cannot adjust to the 24-hour period. Bedtimes are irregular resulting in a variety of problems similar to jet lag.
Weak or nonexistent circadian rhythms
Individuals with weak or nonexistent circadian cycles become sleepy after being awake for a short time and then nap for a few hours. These naps take the place of a full night's sleep.
Treatment of circadian phase disorders
Certain disorders are related to depression or poor sleep hygiene. Properly timed exposure to bright lights may help advance the sleep cycle. Chronotherapy may also be used where the individual sets the bedtime later and later until it has been rotated around the clock and the desired bedtime is reached. To help, establish good sleep habits:
- Go to bed only when sleepy
- Get up at the same time every day
- Establish relaxing pre-sleep rituals
- Exercise regularly
- Keep a regular schedule
- Avoid caffeine within six hours of bedtime
- Avoid smoking close to bedtime
- Try to nap at the same time every day
- Avoid sleeping pills or use very conservatively