Circadian Rhythms and Their Importance to Humanise - Assignment Example

 Circadian Rhythms and Their Importance to Humanise The importance of Circadian Rhythms in mammals has been established by numerous studies and years of continuing research further exemplify the effect of Circadian Rhythms. One of the most significant indicators of the importance of the Circadian Rhythm is the link that has been found between the normal circadian cycle and the health and longevity of otherwise healthy mammals. Kumar, Mohan and Kumar-Sharma (2005) found that “arrhythmic [patterns] from both populations lived significantly shorter than the rhythmic ones, suggesting that circadian dysfunction is deleterious to the physiological well being…even under controlled laboratory conditions” (p. 649). It was significant to note that in this study 25% of the subjects presented arrhythmic Circadian Rhythm patterns and had a shorter life span by 50% compared to the animal subjects with normal circadian cycles. Kumar, Mohan and Kumar-Sharma (2005) in their study further found that the arrhythmic patterns found in the test group also had a correlation to the reproductive success of the mature species with 40% less than their rhythmic counterparts successfully producing viable offspring. The authors noted that although the study did not investigate the causal effects of this it does indicate that further study is necessary. It does, however, demonstrate that the circadian rhythm plays an integral, if not fully understood, role in the viability of the species – not only on an individual basis but also species wide. Doljansky, Kannety and Dagan (2005) note that circadian rhythm typically produced by period s of day and night are manifested in mammals in many of the physiological functions including “appetite, core body temperature, heart rate, blood pressure, and various endocrine and metabolic variables” (p. 598). Much of the cycle is based upon the natural timing of daylight and night. As our study encompassed a full day, examples of the circadian cycle will be demonstrated readily thought each phase of the study with visible, predictable cyclic patterns emerging. Results of the study conducted confirm the findings of researchers that the blood pressure and pulse rate follow a Circadian Cycle. As seen in Appendix A which is the class study findings there is a distinct circadian cycle demonstrated for the pulse rate of the subjects with the peak pulse rate period falling in the 1800 reading systematically reducing to the low pulse rate period at 0600 before again gradually rising. These findings are supported by a study conducted by Moroni, et al (1998) which evaluated both severe cardiac impaired subjects and healthy control subjects. Results of their study found no significant difference in the blood pressure or pulse rate of either group. Rather, both groups exhibited a normal circadian cycle of both pulse rate and blood pressure which was contrary to their hypothesis. The second portion of the class study measured the cognitive functioning at two hour intervals during the day. As surmised in the hypothesis there should have been a distinct circadian cycle manifested. However, this was not the case with distinct functional differences noted by individuals across distinct time periods. What the findings did demonstrate are supported by Pardee, et al (2005) which examined the cognitive functioning to determine whether a universal circadian cycle was noted. Their findings showed that cognitive functioning ability is not solely evidenced by a universal circadian rhythm. Rather cognitive functioning ability is based on a combination of the circadian rhythm, personal preference (simply put day or night people) and the ability to compensate for ‘down-time’ periods in the circadian cycle through cognitive reserve. The motor skill portion of the study consisted of an eye hand coordination test. As hypothesized there were be a general pattern emerge indicative of a circadian cycle. Mean results showed that with only minimal variation the quickest response time was 1800 while the longest response time was at midnight with decreasing times until the times again increased after 1800. Interestingly, Campos, et al. (2001) conducted a similar motor skill test over a four day period with college students. Results of this study found that although there was a very similar circadian cycle noted there were distinct differences between males and females with females performing the motor skills test much more quickly than did their male counterparts, irrespective of time of day. However, the study noted that regardless of gender, the best time to conduct a motor skill test where the shortest times were recorded fell between the hours of noon and 1500 hours exactly mimicking the results of our study. In conclusion, although the circadian rhythm is well documented in the literature and was evidenced by our study result, the study results and literature review demonstrated that we are only in the infantile stages of truly understanding the depth and breadth of this cycle and how a simplistic definition of what it entails and the possibilities for further research would be a gross miscalculation. It can be a great predictor of the possibility of disease or determine the optimum time for testing or merely confirm the detrimental effects of sleep interruption or deprivation. As the research continues however further mysteries of the human body will be unravelled as we further delve into the complicated study of the circadian rhythm and its affect of our quality of life. Works Cited Campos, Tania F., et al. “Diurnal Variation in a Visual-Motor Coordination Test in Healthy Humans” Biological Rhythm Research. 32:2 (2001); 255 – 261. Doljansky, J. T., Kannety, H. and Dagan, Y. “Working Under Daylight Intensity Lamp: An Occupational Risk for Developing Circadian Rhythm Sleep Disorder?” Chronobiology International. 22:3 (2005); 597 – 605. Kumar, Shailesh, Mohan, Ambika and Kumar-Sharma, Vijay. “Circadian Dysfunction Reduces Lifespan in Drosophila Melanogaster.” Chronobiology International. 22:4 (2005); 641-653. Moroni, Carlo, et al. “Blood Pressure Circadian Rhythm and Variability in Subjects with Severe Heart Failure.” Blood Pressure. 7 (1998); 282 – 285. Pardee, Christine V., et al. “Circadian Preference and Cognitive Functioning among Rehabilitative Patients.” The Clinical Neurophysiologist. 19 (2005); 55 – 72. Appendix A Study Findings Biology 155 Lab Section 5 Data Set for Chronobiology Study Fall 2005 Summer 2006 Sample Size: 27 Normal Awakening Time: 6:30-7:30AM Normal Sleep Time: 11:30PM-12:30AM Pulse Rates in beats per minute Time Subject 0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 1 59 53 55 54 59 48 56 60 58 57 63 57 2 49 51 52 49 50 52 55 55 54 56 54 52 3 55 56 57 61 68 76 74 73 75 72 70 66 4 60 54 54 60 52 65 60 66 59 53 65 60 5 59 54 52 56 58 56 58 57 56 66 59 62 6 51 49 49 50 58 59 60 60 60 59 59 59 7     38 37 51 49 50 58 63 68 60   8     35 34 47 45 44 42 46 41 39   9 83 51 54 69 82 55 70 66 64 85 80 80 10 71 46 51 37 66 53 69 66 64 65 63 72 11 67 68 52 54 72 75 75 76 72 73 73 70 12 76 76 101 96 48 104 112 124 104 104     13 50 42 43 43 53 54 47 52 51 50 52 53 14 72 75 77 73 75 72 70 73 84 74 73 76 15 71 65 57 56 66 68 66 61 72 95 81 73 16 56 54 50 52 66 63 65 60 64 60 62 58 17 74 74 73 72 72 70 89 87 83 82 85 81 18 79 82 81 79 82 76 83 81 82 74 82 81 19     49 35 54 52 61 65 60 62 43 39 20 64 60 59 64 63 66 63 65 64 64 60 60 21     97 82 71 75 82 78 95 107 103 80 22 57 55 58 62 68 74 76 75 73 72 71 62 23 73 68 75 79 77 72 81 82 81 83 69 70 24 84 80 60 67 78 69 89 91 100 89 72 79 25 59 67 57 67 64 74 64 69 83 78 72 84 26 78 80 83 75 77 79 80 77 78 79 86 79 27       66 71 61 72 71 70 71 76 72 Mean 65.8 61.8 60.3 60 65 65.26 69.3 70 70.93 71.81 68.2 67.7 Adding Speed in seconds Time Subject 0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 1 45 42 48 40 44 41 42 43 40 57 36 40 2 60 61 65 60 61 58 56 58 60 59 60 61 3 61 67 65 50 52 52 50 52 46 50 52 63 4 45 42 40 40 44 47 50 42 43 40 58 45 5 59.8 63 66 60 57 57.5 56.2 56.5 55.8 55 55.6 57.1 6 55 54 54 52 49 40 56 36 38 38 39 41 7 47 23 30 35 32 30 20 40 35 20 20 27 8 44 39 43 36 48 39 33 37 34 38 34 40 9 36 53 67 32 47 52 41 41 39 37 35 42 10 46 72 63 39 44 52 53 39 42 47 45 44 11 78 60 80 65 60 55 59 61 67 68 63 68 12 57 103 77 47 57 52 56 47 39 48 41 48 13 60 67 69 67 59 59 61 65 60 59 59 60 14                         15 66 52 48 50 50 52 52 54 45 40 48 52 16 70 65 62 60 50 55 52 55 57 50 60 55 17 27 30 35 35 26 25 25 25 27 25 27 26 18 56 65 67 46 52 70 40 52 60 48 42 50 19 120 150 162 149 123 120 135 90 110 115 109 100 20 54 65 70 60 63 64 56 55 56 58 60 63 21 89 89 89 88 87 93 91 90 92 91 92 90 22 62 68 66 52 54 50 51 50 48 52 55 66 23 59 62 60 51 58 63 67 60 59 61 40 50 24 80 74 75 71 63 60 64 63 70 77 74 82 25 65 65 69 68 47 54 58 43 48 49 45 55 26 66 69 69 61 62 66 65 53 60 57 58 61 27       50 32 47 30 38 40 50 52 42 Mean 60.3 64 65.6 56 55 55.9 54.6 51.8 52.72 53.42 52.3 54.9 Eye-Hand Coordination - Time for correct count in seconds Time Subject 0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 1 5 7.5 6 6 6.6 7 6 5.5 7 4 5 5 2 11 10 11 13 10 11 11 12 10 12 11 10 3 33 21 22 27 20 9 11 7 6 11 9 6 4 6 7 6 6 6.5   8 9 8 7 8 9 5 9.9 10.2 10.5 9.8 9.2 9.5 8.9 9 9.1 9 9.3 9.5 6 16 16 16 14 8 10 8 8 9 8 9 9 7 8 7 6 8 10 10 6 11 8 6 10 8 8 11 9 12 10 9 10 12 7 6 5 7 13 9 7 13 10 7 9 8 8 7 7 7 8 9 10 7 12 9 7 7 8 8 6 9 7 7 8 11 8 9 13 8 6 5 5 6 7 7 6 7 12 7 7 7 6 8 5 6 6 5 5 4 4 13                         14 8 9 14 10 5 8 6 7 9 6 8 5 15 10 8 10 8 9 9 7 8 7 8 7 8 16 12 12 10 12 10 10 8 6 10 8 12 10 17 13 8 8 7 6 7 7 7 8 8 7 7 18 6 7 8 5 5 5 4 5 5 6 4 5 19 37 32 25 23 22 20 21 19 23 21 28 30 20 7 10 11 7 8 7 7 7 7 7 8 9 21 5 5 5 5 6 7 4 7 7 5 7 6 22 36 23 20 7 8 10 9 10 6 7 12 8 23 8 9 9 7 8 10 9 8 6 7 7 7 24 14 13 19 16 10 4 5 5 6 7 6 11 25 20 9 9 13 9 14 8 8 7 7 8 9 26 10 10 8 8 10 9 9 9 8 7 9 9 27       21 16 11 10 11 13 16 21 11 Mean 12.6 11.3 11.4 10 9.3 8.94 8.15 8.1 8.196 8 9.13 8.94 Eye-Hand Coordination - Number of Trials with Mistakes Time Subject 0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 1 0 0 1 0 0 0 1 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 1 1 1 2 0 0 0 5 0 1 2 0 0 1 0 0 1 0 1 0 6 0 0 0 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 1 0 0 1 0 8 0 0 0 0 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0 10 1 3 1 0 0 0 0 0 2 1 0 0 11 0 0 0 0 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 0 0 0 0 13 0 1 1 1 0 0 0 1 1 0 0 1 14 4 2 1 0 0 1 0 2 0 0 0 0 15 0 0 0 1 0 0 0 0 0 0 1 0 16 0 0 1 0 0 0 0 0 0 0 0 0 17 2 0 0 0 0 0 0 0 0 0 0 0 18 1 2 2 1 0 0 0 0 0 1 0 1 19 5 3 4 2 1 1 0 0 0 0 1 2 20 0 0 1 0 0 0 0 0 0 0 0 0 21 0 0 0 0 0 0 0 0 0 0 0 0 22 3 2 0 0 0 0 0 0 0 0 0 0 23 0 1 0 0 1 1 0 0 0 0 0 0 24 5 1 2 0 0 0 1 0 0 0 0 4 25 3 0 0 1 0 0 0 0 0 0 0 0 26 0 0 1 0 1 2 0 0 0 0 0 1 27       1 3 0 0 0 0 0 0 1 Mean 0.92 0.62 0.65 0.3 0.2 0.259 0.11 0.19 0.222 0.074 0.15 0.37 Read More