Circadian Rhythm

A rhythm is something that is regularly repeated. All living organisms experience rhythmic changes which tend to coincide with seasonal or daily environmental changes. Most organisms have an internal biological clock called endogenous pacemakers, which are influences by external environmental factors called exogenous zeitgebers, these control periodic changes. The sleep wake cycle is a circadian rhythm that repeats itself every 24 hours. However these can become desynchronised, resulting in a disruption of your biological rhythm. It can be disrupted by many factors, including Jet lag and shift work.

As beneficial as it sound, some people might suffer difficulty as the time switches. Talking about the circadian rhythm or the body’s natural clock, pushing

14. Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24-hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23,24, 25, 26, and 25.

Circadian rhythms occur every 24 hours; an example of a circadian rhythm is the sleep-waking cycle. We are diurnal animals who are active during the daytime and asleep at night, other animals are nocturnal they are active at night but asleep during the day. The circadian rhythm depends on the interaction of physiological and psychological processes to be tuned into the sleep-waking cycle so energy is provided when needed. As diurnal humans we have a fairly stable sleep pattern with the time we go to sleep and the time we wake up, this consistency suggests an internal mechanism controls sleep, endogenous pacemaker. However, this can be overridden by external factors, exogenous zeitgebers.

The circadian rhythm is very important in analyzing ones sleep pattern like when they are a sleep pattern like when they are a sleep and when they are awake. One’s normal circadian clock is based on light-dark times over 24 hours.()

Regimented sleep schedule: By sticking with a regimented or strict sleep schedule, your circadian rhythm should adapt. Those with variable sleep schedules may have a circadian rhythm that isn’t aligned with their sleep schedule, thus resulting in all types of physiological chaos. Decreasing this physiological chaos with a good sleep schedule may also reduce the

Circadian rhythm is another sleep disorder that has to do with our body functions. In this case, our body clocks are off, due an internal change or external factors like a change in time zones or regions where a midnight sun occurs during a 24-hour period. Bright lights in a room have a similar effect on sleep.

In another study involving twelve adult participants between the ages of 18-59 who had a diagnosis of Seasonal Affective Disorder, light therapy was found to help correct the natural melatonin secretion cycle (Rice, Mayor, Tucker, & Bielski, 1995). Melatonin is a hormone secreted at nighttime by the pineal gland, and plays a role in human sleep and wake cycles by aiding the process of sleep.

There are two cells in the retina that determine how well we see color, shapes and detail. The rods, which are located in the retina, are responsible for our vision in low light. They do not facilitate color vision, and have a low spatial awareness. The cones react in higher light levels and are responsible for color and details, as well as depth perception. When the light hits the rods and the cones a chemical reaction occurs giving us our vision.

Non-24-Hour Sleep-Wake Disorder, short for Non-24, is a chronic circadian rhythm disorder that affects people that are completely blind. The circadian rhythms control the body clock and regulate sleep-wake cycle and various other cycles that are critical in the body. In most people, this body clock runs marginally longer than 24 hours. This means that rather than cycle on a 24-hour day, most people’s natural rhythms actually run a bit longer. Whether the cycle runs two minutes or 30 minutes longer, patients with Non-24 have these minutes add up day after day, few days adding to a few more the next. Eventually causing evident changes in one’s body. Their body’s circadian rhythm becomes out of sync from regular day and night cycle.

Light helps to regulate circadian rhythms, neuroendocrine responses, and seasonal cycles. (Brawley & Noell, 2008, Pages 2 & 11). Circadian rhythms help derive patterns of sleeping and eating. These circadian rhythms can be triggered by light and are

This is a very interesting subject. Melatonin is secreted by the pineal gland, which is what makes us sleepy. Melatonin is produced when it is dark. In the dark, eggs are protected in women that are fertile and ovulating. The eggs are better preserved and healthier. Women who are already pregnant who do not get enough sleep and have enough time in the dark, are likelier to have children born with ADHD and other behavioral problems. At least 8 hours is recommended for women, especially in the final trimester, to help produce sufficient melatonin. This helps the fetus receive sufficient melatonin which helps his/her biological clock as well as helps the fetus brain.

Aside from noticing night and day and clocks our body has its own system to tell us when to sleep and when to wake, our circadian rhythm. The human body naturally runs on a twenty five hour clock, so living on a twenty four hour schedule is often hard on the body because it loses an hour each day. On top of this natural loss most people do not get the right amount of sleep each night which can cause a whole host of problems. This is part of

 Jet Lag: internal biological clocks collide with external clocks as a result of moving across several time zones.

Many individuals, especially adolescents, do not function well early in the morning. “…many teenagers are going to school with their brains essentially in sleep mode” (Kaufman, 2001). This makes it difficult to retain information and in return use the information they have learned later on according to Robert Gerson, a physician and parent (Heinen, 1996). There is a reasonable explanation for why adolescents need the sleep they need at the times in which they need it, or do it for that matter. “Their circadian rhythms, determined by release of the hormone melatonin and other factors, were telling them to stay up later (even if their homework was finished and the day’s chores complete) and to get up later. On basic biological level, many had no more control over that circadian switch than they did over growing facial hair or breasts” (Kaufman, 2001).