Essay Example on Human Circadian Rhythms

Introduction

Circadian rhythms are the mental, physical, and behavioural body changes taking place in an individual within a cycle of 24hrs and are mostly influenced by light and darkness. The brain serves as a master clock for the proper functioning of the body systems with an influence on the environmental signals by synchronizing dark and light (Zisapel, 2018). However, these circadian rhythms play a pivotal role in maintaining physical and mental health conditions in human beings, including other living things. Therefore, according to the U.S. Department of Health and Human Services, circadian rhythms are natural processes that respond to dark and light, affecting animals, plants, and other living things. In their article "National Institute of General Medical Sciences," the author's main point was to address the effects of circadian rhythms in the human body and its influence on sleep in connection with the brain. The author's interest was also centred on knowing some factors that cause circadian rhythms changes in human beings.

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Significance of Circadian Clocks

Besides, both authors Roenneberg and Merrow, in their article "The human circadian clock entrains to sun time," emphasized the significance of circadian clocks among individuals in working environments and the education sectors. The authors wanted to determine how individuals can be affected by a change in time-saving to and from daylight within different environmental settings. On the other hand, the main idea of the author's Mien et al was to test if retinal cones can enhance circadian resetting responses in individuals when they are exposed to darkness and alternating red light. As indicated in their journal "Effects of Exposure to Intermittent versus Continuous Red-light on Human Circadian Rhythms, Melatonin Suppression, and Pupillary Constriction," the participants were exposed to both white and red light during the study to determine the changes in human circadian systems.

On the same note, authors Wehrens et al in their article "Meal Timing Regulates the Human Circadian System," wanted to know how a delay in meals affects both plasma glucose and circadian rhythms in the human body system. Authors Blume et al in their article "Effects of light on human circadian rhythms, sleep, and mood," the author's aim was to prove if individuals' mood and sleep can be affected by circadian rhythms through the retina. Consequently, author Zisapels' point of view was to determine how melatonin can influence human sleep and the regulation of circadian rhythms in a cycle of 24hours day and night, as indicated in the article "New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation."

Summary

According to the U.S. Department of Health and Human Services, the author's main point was to prove if the human body can sustain its circadian rhythms using both master and biological clocks obtained from light. The research shows how the brain, which serves as the master clock, receives light from the environment. Apart from the sleep hormone melatonin, the authors considered light from the sun as one of the environmental factors to determine how changes in the human body can influence sleep. Authors Roenneberg and Merrow emphasized how human beings are affected by daylight and darkness by monitoring their behavioural changes within the working environments, schools, or medical sectors. Both authors considered the gradual change in shifts among workers as the most appropriate for their study to realize how circadian rhythms can influence humans' sleep.

Additionally, authors Mien et al did assessments on body temperatures, melatonin, heart rate, and cortisol among the volunteers in the laboratory. The assessments were done before and at the end of exposure to light for six hours so as to realize the suppression of melatonin levels. Typically, authors Wehrens et al did an investigation on the effect of five hours delay of meal intake in human beings to prove if it can interfere with the individuals' sleep. The author included the three meals, breakfast, lunch, and dinner, to realize the plasma concentration in the human body and circadian system in sleep (Mien et al., 2014). However, the authors ought to have started from the lowest time possible, like two hours delay, to determine how fast the participants can fall asleep instead of five hours meal delay. Author Zisapel's hypotheses results showed that melatonin hormone normally produced at night increases sleeping rate, especially to insomnia patients. The melatonin hormone also acts as a biological clock that serves as a time signal in the human brain and enhances sleep. The author reiterated that the unusual circadian rhythms and poor sleep quality are connected to increased mortality and poor lifestyle, high risks of mental disorders, including cardiovascular health problems.

Review and Evaluation

Usually, circadian rhythms are generated by clocks that are naturally produced in the absence of environmental signals. These circadian clocks have the capability to influence the biological processes and behavioural functions in humans and can be demonstrated in the laboratories under room temperatures (Johnston et al., 2016). Authors Roenneberg and Merrow wanted to know if individuals are aware of the circadian clock and human disease at the final stage of the literary work. Their research question is an indication that the readers are already aware of what to expect within their work and can easily understand the final results of the study. However, some authors failed to indicate the research questions in their articles, giving readers a hard time interpreting the main point. For instance, authors Wehrens et al and Zisapel did not highlight the research questions in their articles, making the reader search for additional information about the study topic.

Subsequently, qualitative, experiment, questionnaires, and quantitative are some of the methodological approaches in the journals and articles in this paper. Roenneberg and Merrow used an experimental approach and tools to show how circadian systems cause diseases, including their treatment and prevention. The experiment method was appropriate because it gives a step by step procedure on how the circadian clock can affect human health and sleep behavioural changes. Also, Roenneberg and Merrow incorporated a qualitative research method to study the ability of sleep among the workers in shifts, alongside other methods like zeitgebers for chrono-medical treatments. Besides, it would be appropriate to include unemployed participants, especially from the rural setting, to determine the effects and create awareness on the diseases associated with circadian rhythms in the body.

Also, the authors included the questionnaire method to get the correct participants for the study. Roenneberg and Merrow provided a clear view of how the participants were recruited for the exercise through signed consent. Obtaining a signed consent shows that the participants were willing to take the tests upon an agreement. Unfortunately, the authors only concentrated on males but not females. Wehrens et al also included only men as their only subjects of study, and there are no reasons for their choice. Thus, the readers may develop some negative assumptions by saying that circadian rhythms only occur in men (Roenneberg, & Merrow, 2016). Besides, the authors incorporated young and healthy individuals for the laboratory tests, making the readers doubt why the aged are not part of the study. The circadian rhythms occur in humans, which means that both males and females inclusive of all ages despite their health status. As a result, the authors should tell readers why they took only young and healthy subjects for the study.

Typically, Roenneberg and Merrow observed that the sleeping effects on human behaviour were most common with sleep performance and deprivation. Both the authors also observed that human chronotype variance was increased by the characteristic of current lifestyle with weak zeitgebers, making individuals run free or become arrhythmic during their sleep-wake behaviour. There was a lack of enough sleep from patients with dementia, resulting from either light-dark cycles with low amplitudes or disease-associated pathology from the study. Another observation was that zeitgebers entrain the human clock during sun time. I agree that the author's Roenneberg and Merrow interpretation about findings via other methods like zeitgebers and other reviewed sources was appropriate and are in line with the cited works. In the article, the authors provide evidence to support some of their interpretations, making the study valid. For instance, the authors stated that "several of these initial findings, especially concerning cancer and metabolic diseases) have been validated with evidence from highly controlled experimental approaches." After the statement, there is a reference to support the interpretation, making it easier for the reader to understand and follow up on the study.

Conclusion

Focusing on the U.S. Department of Health and Human Services study, the authors gave a chronology of what the readers expect to know about circadian rhythms in humans before their main illustrations. Through their article, a reader can get the intended information and answers to the questions about the topic. On the same note, perfect research requires more information about the topic discussed for the readers' satisfaction. Therefore, the U.S. Department of Health and Human Services authors provided less information about the topic of their study and incorporated the use of more diagrams for illustrations. In this case, the diagrams give the readers information on how the circadian affects the human body in conjunction with the brain, but it still seems to be a shallow work done as some readers may not easily interpret the 24hour-cycle.In their article, the authors never did any experiment for research purposes. Therefore, the article tends to provide less information about the circadian rhythms in humans and its effects.