Circadian Rhythms

CIRCADIAN RHYTHMS: GIVING ORDER TO YOUR DAY

OVERVIEW: The human body is programmed to sleep during the night when it is dark, and to rise during the day while there is light. This cycle of alertness over a 24 hour period is called the circadian rhythm. The work "circadian" literally means "around the day." As we spend more time up at night, trying to make up for it with daytime sleep, we can develop disorders of our circadian rhythms. Often these disorders are temporary, as when you suffer from jet lag. Two other circadian rhythm disorders are "delayed sleep-phase syndrome" or DSPS and "advanced sleep-phase syndrome" or ASPS. In DSPS, the patient stays up too late and can't get up in the morning. In ASPS, the patient goes to sleep too early in the evening and wakes earlier than they wish.

CAUSES: Jet lag is of course caused by crossing time zones so that you are alert when it is night, and feel like sleeping during the day. It is a temporary disturbance and disappears as you get adjusted. Other circadian rhythm disorders are caused by working nights or irregular shifts. Lifestyle issues can make a person stay up later than they should. Pregnancy and having a new baby mess up your sleep schedule. Depression can cause ASPS. Working the night shift causes circadian rhythm problems, and neurological diseases such as Alzheimer's cause them, too.

SYMPTOMS: Getting your sleep off schedule can cause all kinds of uncomfortable symptoms. It is often hard to get to sleep and hard to stay asleep. If you do get to sleep, the sleep might not be as refreshing as you need. Circadian rhythm disorders cause a decrease in work performance, concentration, learning, and thinking. It can cause headaches and stomach aches. It can cause poor coordination, poor memory, and just a sleepy, drowsy feeling when you need to be alert. All of these ailments can sap your motivation.

DIAGNOSIS: One of the best things you can do to help your doctor determine if you have a circadian rhythm disorder is to keep a sleep log for a couple of weeks. For best results, a sleep log or diary should include more than just how long you sleep. Include what you ate, how much and when you exercise, medications you took, and even your feelings throughout the day and night. The more information you can give the doctor about your schedule, symptoms, and habits, the better advice you are likely to get. You may have to have a CT scan to check for neurological disease. If keeping a diary does not work for you, there is a device called an Actigraph that you can wear on your non-dominant wrist. It keeps track of the times of the day and night that you are active or still. It can be more accurate than self-kept records.

TREATMENT OPTIONS: One unusual type of therapy that can be very helpful for circadian rhythm problems is bright light therapy. Bright light, over 6000 lux and lasting 30 to 60 minutes, can be used in the evening for people with ASPS. People with DSPS can be induced to get up earlier if bright light is used in the morning hours. Another treatment option is chronotherapy. This refers to changing the behavior so that each successive day you gradually move your bedtime and rising time a little closer to where it needs to be.