Biorhythm Disorders: Circadian Rhythm Disorders, Jet Lag, Shift Work Sleep Disorder and Seasonal Effective Disorder
Our “Internal Clock”
Our sleep and wake cycles are tightly controlled by a special area of the brain, which in turn is set by our exposure to bright light. Also, light is energizing and increases alertness. For example, it is much easier to get up in the morning when sunlight is streaming in through bedroom windows. Normal indoor lighting is not bright enough to make an adequate difference.
This phenomenon accounts in part for the difficult challenge confronting night shift workers. They must attempt to stay awake when their body clock is commanding them to sleep, and they must try to sleep when their internal clock is set for wakefulness! It has been shown that night shift workers get 1.5-4 hours less sleep on the average than day shift workers, and their sleep is of poorer quality. Any daylight in the bedroom when they are attempting to sleep will compound their difficulties. Furthermore, many third shift workers feel guilty if they are not awake to take care of errands and household tasks during the day which further limits their sleep.
Shift work imposes a terrible strain on the body. Shift workers have increased rates of gastrointestinal disorders, heart attacks, depression and other conditions.
Seasonal Affective Disorder (The “Winter Blues”)
An additional potential problem related to light is that of seasonal affective disorder (“SAD” or the “winter blues”). Symptoms of this widespread condition are common in the northern United States and rampant in northern Canada and Alaska. SAD involves depression that occurs specifically when there is less sunlight. It is associated with lethargy, difficulty awakening in the morning, a tendency to sleep excessively and a craving for carbohydrates that can cause or aggravate weight gain.
Many people suffer from inherent biorhythm problems. Some find it difficult to fall asleep until hours after what would be considered an ideal normal bedtime for them, and they may fail to wake up in time for work or school (“phase delay syndrome”). Then, they must fight against overwhelming grogginess when others around them feel refreshed and energetic. Still other people cannot stay up as late as normal individuals, and they are frustrated by the fact that they wake up hours earlier than necessary and cannot return to sleep (“phase advance syndrome”).
Adolescents are particularly prone to “phase delay syndrome”. This phenomenon helps explain their tendency to stay up late and sleep inlate. It is not simply willful behavior designed to frustrate parents! And it can have significant consequences. Tragically, many school systems are adopting progressively earlier “start times” and the academic performance of their students suffers as a consequence.
Jet lag is a widespread example of a biorhythm problem imposed by external circumstances. It relates to the fact that travelers’ internal clocks are not instantly reset to correspond with actual clock time at their destination. The results? Less than peak performance during important business trips, and reduced enjoyment of vacation travel (all the more unfortunate given the progressively shorter vacations being taken by Americans).
What can be done about these common problems related to light and our internal clock?
What about melatonin?
Melatonin is a hormone released from the brain’s pineal gland. It is involved in our internal clock and its secretion is influenced by light-dark cycles. However, taking it by mouth does not appear to be a good solution. Dosages found in over the counter melatonin preparations result in body concentrations that are many times higher than normal levels. It has not been established that such large amounts are safe. Also, these products are not regulated to ensure purity: of potential concern given the epidemic of illnesses and deaths related to another over-the-counter “natural sleep aid”, tryptophan until it was removed from the market. Finally, melatonin often is not effective.
Use of sleeping pills (for example, during flights across time zones) is not necessarily a good idea.
It was ironic that one of the first reported cases of severe mental impairment and disorientation from Halcion occurred in an American neurologist who took the drug during a trans-Atlantic flight to Europe for a medical meeting. He had hoped that the medication would help him sleep well during the flight such that he would arrive alert and refreshed. As it turned out, he apparently was so confused that he was non-functional!
The best answer to the above problems is the simplest and most direct–applied common sense measures: including dedication to protecting your sleep –you cannot survive without adequate amounts of adequate quality sleep!–and the use of light or darkness at the appropriate times. Use of special light devices can shift sleep cycles, improve ease of awakening, and effectively treat the “winter blues”! Also, it now is possible to ensure a dark bedroom to improve sleep during daylight hours.
A full service sleep disorder center should be able to help you deal with specific biorhythm problems.