Circadian sleep rhythms are our natural cycles of sleeping and waking periods during a 24 hour period. It is more common to hear of appeals for business to allow workers to have a brief nap during the work day. Many countries operate on a “siesta” basis, with businesses closed during certain afternoon hours to allow for some rest.
The idea of getting to bed and dropping off right away by 9 pm every night, then sleeping through the night, then waking refreshed and ready at 5 am is a distant dream for many.
Disruptions in the natural cycles of sleep and waking are considered to be sleep disorders. There are two types of causes: Primary, which is unrelated to any internal physical or mental problem, and secondary, which is related to physical or psychological disorder or drugs and alcohol.
According to the DSM-TR, there are parasomnias and dyssomnias. Dyssomnias occur when the quality, timing or amount of sleep is disrupted. Parasomnias relate to abnormal behavorial or psychological events that occur while sleeping.
Circadian rhythm sleep disorder is one of the dyssomnias. Each person has their own internal sleep and waking cycles for a 24 hour period. The disorder occurs when happenings or factors affect natural sleep patterns over that 24 hour period. In some cases, individuals have a sleep/waking period that is not 24 hours long.
There is either a persistent and recurring set of disruptions to the natural sleep order or there is unequal balance in the need for sleep on an internal and natural cycle, and the social, work related and other external demands that are placed on a person prevent them from sleeping on their internal natural cycle.
There are four subtypes of this disorder: delayed sleep phase, jet lag, shift work and unspecified. In worst cases, there is impaired function in various areas, such as job related, interpersonal and social.
Delayed sleep phase is a function of psychosocial stresses where the sleep cycle disagrees with the demands of society. While the individual sleeps normally, once they get to sleep, they cannot go to sleep at a time that is dictated by society, resulting in staying up late and getting up later. A clear example is with 7 percent of adolescents who are more likely to develop the disorder. 4 percent of adults are estimated to have delayed sleep phase problems. It takes retraining and adoption of changed bedtimes for delayed sleep phase to be taken care of. Otherwise, an inability to get to work or school on time, and even parenting problems can occur.
The demands of technology, such as flying, can take us to a completely different time of day in a short period of time, subjecting us to a complete change in daylight and business hours! This is the jet lag circadian rhythm sleep disorder. Changing time zones rapidly can place demands on us to be sharp while socially interacting, making decisions or having to perform on the job when we feel like we should have been asleep for hours. When crossing a lot of time zones on a regular basis, the condition can get worse.
Shift work is a major disruption to circadian rhythms, especially with children, serving in “on call” or having military duties that require shift changes, doing elder care and working in mid and night shift work will conflict with our natural need for regular sleeping and waking cycles.
Perhaps the tendency for employers to require more overtime, or to impede in workers off duty hours, especially with conferencing over multiple time zones might be adding to circadian rhythm problems. Over half of night shift workers are said to have this disorder.
It takes a certain time to “wind down” after working, doing the after work shopping, childcare and chores, then to get ready to sleep, and excessive intrusion from the workplace can disrupt the patterns that used to flow normally when people left work for the day.
The unspecified type of circadian rhythm sleep disorder is a hold all for circadian problems that are not from the above causes. Some people may have a longer than 24 hour sleep/wake cycle, and will be sleepy during the daytime and wakeful during the socially acceptable hours for sleeping deeply. Extreme patterns involve inability to know when they will be able to sleep or stay awake. The elderly, disabled and retired can suffer from this type of insomnia when they enter a part of life where there are far fewer social demands for a regular sleep pattern.
Encyclopedia of Mental Disorders: Sleep Disorders
Encyclopedia of Mental Disorders: Circadian Rhythm Sleep Disorders