Circadian rhythms are natural changes in the body that happen roughly every 24 hours and regulate the sleep-wake cycle. These changes may include core body temperature, hormone levels, alertness, and appetite. So, if the sleep-wake cycle isn’t synchronized with the day-night cycle it means that a person is suffering from some type of circadian rhythm sleep disorder (CRSD).
Circadian Rhythm Sleep Disorders
Common CRSDs include advanced sleep phase disorder (ASPD), non-24-hour sleep-wake disorder (non 24 /free-running disorder), and delayed sleep phase disorder (DSPD).
Advanced Sleep Phase Disorder (ASPD)
A person suffering from advanced sleep phase disorder falls asleep quite early in the evening and wakes up very early in the morning without being able to continue sleeping.
Prevalence: ASPD is the least common of all three circadian rhythms sleep disorders due to the fact that people don’t usually seek professional help because it doesn’t make them late for school or work.
Non-24-Hour Sleep-Wake Disorder (non-24)
The non-24, also known as a free-running disorder, is a sleep condition in which a person’s day length is much longer than 24 hours meaning that each day he/ she goes to bed later than the previous.
Prevalence: Surprisingly but true, more than 50% of blind people have a free-running disorder although sighted people can have it too, which is quite rare.
Delayed Sleep Phase Disorder (DSPD)
If a person is unable to fall asleep until late at night it means that he/ she is suffering from DSPD. This disorder results in sleeping late in the morning or sometimes into the afternoon.
Prevalence: Exactly 0.17% of adults, or about one in 600, have been clinically diagnosed with DSPD. Still, since people aren’t familiar with it, it usually goes undiagnosed.
Circadian Rhythm Sleep Disorders Causes
Namely, there are various potential causes of these disorders such as remarkably long or short circadian rhythm, lack or over-sensitivity to light, intrinsically photosensitive retinal ganglion cells deficiency, long elimination time, or production deficiency of melatonin, differentiation in sleep timing, etc.
Circadian Rhythm Sleep Disorders Impact
Living on a normal schedule while suffering from one of these disorders can be quite challenging since these people don’t usually get the proper amount of sleep or their sleep is of poor quality.
The most common issues they face are sleep deprivation, fatigue, depression, lack of concentration, difficulties to function normally, and over time, this could even lead to diabetes, fibromyalgia, cancer, and other serious health problems.
Circadian Rhythm Sleep Disorders Diagnosis
Getting a physician’s referral to be examined by a sleep specialist is the first obstacle these people come across because primary care doctors usually treat such disorders as insomnia, prescribe sleeping pills, or blame depression.
But, once these patients get to visit a sleep specialist, it becomes easier. They first undergo a sleep study which usually rules out other sleep disorders like sleep apnea and restless legs syndrome. Then, they rule out narcolepsy by doing a multiple sleep latency test (MSLT).
However, although ruling out these sleep disorders is a good thing, the downside is that sleep studies are performed during normal sleep hours which isn’t valid for those suffering from a circadian rhythm sleep disorder.
Circadian Rhythm Sleep Disorders Treatment
Once a circadian rhythm sleep disorder is diagnosed, the patient should try a treatment to help him/ her fit normal sleep hours. The most common treatments include melatonin (taken four to eight hours before bedtime to help change circadian rhythm), light restriction (limiting light exposure to just extremely dim light during the evening), and light therapy (bright light exposure) which can all be used together.