Circadian Rhythms Disorders and Sleep Phase Syndrome

Sleep forms part of human’s biological need torest. As a person sleeps, the various physiological processes of a human bodyfiguratively put into an apparent arrest and some parts of our system that weremostly exploited can be replenished for future use.

However, imagine a system so disrupted that ournormal scheduling for sleeping and waking is totally altered. Some people tendto sleep early and wake up early in the morning and some cannot sleep early andas a consequence, wakes up late.

These and other sleep-related problems aremanifestations of a malfunctioning biological circadian clock and characterizeseveral forms of Circadian Rhythm Syndrome. Circadian activity is a unique by24-hour period or cycles in which our body is physically patterned. 

24-hour vs. 25-hour cycle

Earth rotates around the sun in a 24-hour cycle, soas our body functions in this 24-hour time schedule. All living organismscharismatically subscribe to this cyclic resting and activity patterns so thattheir body could function in sync with the environment in which they live.

Although humans externally operate under a 24-hourenvironment, research found that our body clocks evidently works significantlydifferent than what we see in the environment.

It shows that the human body closely behaves as ifit were under a 25-hour environment. Convincingly, humans’ reluctance to wakeup at a required time and sleeping late at night probably explains this theory.

To compensate for this discrepancy, the body usestime “cues” to effectively counter-manage this asynchronous rhythmical. Settingan alarm helps us wake up at a designated time of the day and allows us tofunction as if it were under the 24-hour rhythmic schedule.

Dark vs. Light

Light and temperature provides the determiningfactor by which the body responds to the 24-hour activity period. The presenceor absence of light mainly affects the part of the brain, which paces yourbodily activities.

It was understood that the fundamental locus orlocation of our biological clock is the brain specifically in thesuprachiasmatic nucleus (SCN) of the hypothalamus.

In complex animals like humans, hypothalamus formspart of the autonomous nervous system, which in part, controls the functions oforgans that are not voluntarily controlled, hence involuntary. Involuntary,meaning, they are not governed by conscious will to act. These includebreathing, heartbeat and intestinal digestion.

Eyes, Light and SCN

One interesting point to make is that the locationof SCN is just above the optic chiasma (cross). Optic chiasma can is describedas a location where optic nerve fibers meet and cross (chiasma-cross).

It is fitting to say that; the perception of lightthrough the opening in the eyes triggers the wake/sleep patterns in humanssince this is one way the organism receives such physical message.

As retina (a portion of the eye where initial imageof an object is stored) traps light rays, an optic fiber relays the image tothe brain via characteristic electrical pulses.

This unique sensory impulse is carried along theoptic fibers to the occipital lobe (rear part) of the brain and is perceived asimages. The proximity of the optic chiasma to the SCN perhaps provides theopportunity for the hypothalamus to “sense” the referred electrical impulses.

Forms of Circadian Rhythms Syndrome/Disorders

Circadian Rhythm defects can come many distinctforms depending on the amount and timing of waking up and sleeping. Others, asin the case of Seasonal Affective Disorder (SAD), result in the changes in thelength of day and night.

People who tend to sleep at a later time of the dayand wake up late as well are said to be exhibiting Delayed Sleep Phase Syndrome(DSPS). These people tend to develop insomnia, an abnormal inability to takeadequate amount of sleep due to not being able to sleep at the right time ofthe night.

Still, other people, especially the elderly, aremore likely to sleep early around 7:00 PM and consequently wake up early around 1:00 AM or 2:00AM. This is a symptom of disrupted natural biological rhythms known as FamilialAdvanced Sleep-Phase Syndrome (FASPS).

The amount of a substance called melatonin is also perceivedas a motivating factor in sleep-related disorders in humans. In a study amongvertebrate mammals, melatonin is secreted in response to the absence of light.

This means more melatonin is secreted in the periodof darkness and less in the presence of light. It presupposes the idea thatmelatonin is related to the 24-hour sleep/wake cycle of every human being.

Recommendations

With the knowledge gained in the precedingdiscussion, it can be assumed that the presence and absence of light affects oursleeping/waking schedule. With these in mind, keep yourself committed to yourschedule to rest and sleep and set aside things, which are not reallyimportant.

Keep your room as dark and gloomy as possible, tomake it easy for you to sleep. Colorful objects stimulate your senses anddisrupt sleep. Keep it ventilated and air-conditioned.

Studies show that as we sleep, our body temperaturedrops and allows the neurotransmitter melatonin to be produced at a rapid pace.

Keep those things in mind and do not forget to seekmedical help should your condition progresses.