What is the Biological Clock?

The “master clock” or the biological clock , controls circadian rhythms consists of a group of nerve cells in the brain (in the hypothalamus) called the suprachiasmatic nucleus, (SCN), it regulates your circadian rhythm.

What are Circadian Rhythms and how do They Affect Your Sleep?

First of all, circadian rhythms are physical, mental and behavioral changes that follow a roughly 24-hour cycle; it influences sleep-wake cycles, hormone release, body temperature and other important bodily functions. Furthermore, the brain relies on “outside” influences called zeitgebers to keep you on a normal schedule. The most obvious zeitgeber is sunlight. Other zeitgebers are ambient temperature, sleep, social contact, physical activity, and even regular meal times. They all send “timekeeping” clues to your brain, helping keep your circadian rhythm running on schedule.

What is the Circadian Rhythm Disruption?

Any time that our normal 24-hour circadian rhythm is altered or interrupted, it will have physiological and behavioral impacts.

What are the symptoms of circadian rhythm disorders?
In circadian rhythm disorders, there is a continuous or occasional disruption of sleep patterns. This disruption is either a malfunction of the internal body clock, or a mismatch between the internal clock and the external environment regarding timing and length of sleep. As a result, those with circadian rhythm disorders experience insomnia at certain times and excessive
sleepiness at other times. This causes problems functioning at work, school or in social activities.

The circadian rhythm disruption, which will lead to different type of sleep disorders is including:

Delayed Sleep Phase Syndrome: Some people find that it is difficult to fall asleep before 2:00 am and that they have trouble waking up in the morning (they like to wake up after 10 am). This problem is very common in young adults and can interfere with school or college schedule.

Advanced Sleep Phase Syndrome: In contrast, this is a disorder where sleepiness occurs well before the desired sleep schedule. A person feels the urge to go to sleep between in early afternoon around 6:00 and 8:00 p.m. and wakes up too early between 2:00 and 3:00 am. This is more common among older adults.

Irregular Sleep-Wake Rhythm: This sleep disorder applies to people who do not have a regular sleep pattern and who often have changing sleep periods and irregular times of alertness and sleepiness.

Shift Work Disorder: Shift workers are those who work nontraditional hours such as night shifts or rotating shifts. They may not get the same amount of sleep during the day, they may have problems adjusting to sleep schedule, feel less energetic, and struggle with focusing,

Finally, jet Lag: Occurs when travelers pass through different time zones, your body’s clock will be different from your wristwatch. For example, if you fly in an airplane from New York to Dubai, you “lose” 8 hours of time. Therefore, when you wake up at 8:00 a.m., your body still thinks it’s 12:00 midnight. Making you feel groggy and disoriented. Your body’s clock will eventually reset itself, but this often takes a few days.

How are circadian rhythm disorders diagnosed?

Certainly, diagnosing a circadian rhythm disorder is challenging and often requires consultation with a sleep specialist, who will help rule out other sleep and medical disorders. Some circadian rhythm disorders are prone to be misdiagnosed as narcolepsy or co-exist with insomnia or sleep apnea. Your doctor may order overnight and daytime sleep studies.