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Introduction
Blood pressure refers to the force exerted by the blood on the walls of the artery. Measuring the blood pressure is done in mmHg or millimeters of mercury and is given by two numbers. The number on the top shows the maximum pressure that is exerted by the heart while beating also known as systolic pressure. The bottom number shows the quantity of pressure in the arteries between heartbeats also known as the diastolic pressure. The difference that occurs between the top number and the lower one is referred to as the pulse pressure. Heart rate is the number of times that the heart beats in a minute (American Heart Association, 2012).
An increase or decrease in pulse pressure is usually an indication of heart problems. This is especially noted in older people who are in a greater risk of developing cardiovascular diseases. This is partially due to the normal changes taking place in the body due to age. Additionally, there are chances that plaques may develop in old age resulting to a decrease in the flow of blood into the heart muscles, as well as the brain. In the medical field, hypertension is described as that situation where the blood pressure readings are above 120/80mmHg. A blood pressure reading of less than 120/80 is usually considered to be normal while a pulse pressure of 40mmHg is considered to be normal. Incidents where the pulse pressure is low are an indication that there are chances that the heart has a serious problem. Pulse pressure higher than 60 is considered to be one of the risk factors for developing cardiovascular disease while values less than 40 may be an indications that the heart is functioning poorly (American Heart Association, 2012).
There are several dangers of an elevated blood pressure. Some of these dangers include artery hardening, stroke, heart disease development, and atherosclerosis. On the other hand, dangers of low blood pressure include dizziness and fainting. Some of the factors that may lead to elevated blood pressure are smoking, stress, some medications and medical conditions such as sleep apnea, chronic kidney disease, as well as thyroid disease (NIH, 2012). Other causes of temporary change in blood pressure include activities such as running and other sport activities. Sometimes is thus natural to have a rise or a fall in blood pressure as one change activities or when there is change in emotions. These are, however, temporal changes after which the body is able to regulate the normal blood pressure after the activities are over through osmoregulation (WebMD, 2013).
This experiment aimed to measure blood pressure and pulse and to understand the meaning of these readings. The experiment also aimed to identify why these factors may change in response to daily activities and how the body controls homeostasis with regard to blood pressure.
Methods
Health and Safety
Subjects who were asthmatic were excluded from the exercise in order to prevent cases of exercise-induced asthmatic attack. Doing exercise on the cycle ergometer while wearing skirts or dresses was avoided. Long loose hair was also avoided by tying it up or making sure it is at the collar level.
Materials & Methods
The materials that were necessary for the experiment were electronic sphygmomanometer, couch, stopwatch, two basins of water (0OC and room temperature) and ergometer.
The effect of Different Levels of Activity on Blood Pressure and Pulse Rate
The activity was done in a group with one member being the subject. The blood pressure (BP) and pulse readings of the subject were taken by allowing the subject to sit and rest for 15 minutes. At the end of the 15 minute rest period, the blood pressure and pulse rate of the subject were recorded. The subject was allowed to exercise on the cycle ergometer for 5 minutes at about 5kj/min. At the end of the 5 minute exercise period, the blood pressure and pulse rate of the subject were recorded.
Effect of Body Posture on Blood Pressure
Measurements for BP in the left arm were taken at the level of the heart while lying, immediately on standing, standing and sitting and the results recorded. The subject was requested to lie horizontally, and measurements for BP were taken in both arms with the arms held above and below heart level.
The Effect of Cognitive Activity and Sensory Inputs on Heart (pulse) Rate
The pulse of the subject was taken and recorded for 1 full minute as follows. First, the pulse readings were taken in a resting position as the baseline readings. Secondly, the subject recited the timetables for 3 times upwards for the first 2 minutes after which the pulse rate for the next minute as the subject recited the timetables were recorded. Thirdly, the subject was given a massage on the right foot for 10 minutes while keeping the fingers on the pulse rate of the subject. Towards the end of the 10minutes, the pulse rate was recorded for 1 minute. Lastly, the subject was asked to think about exams or something that could cause the subject to feel stressed or fearful for 1 minute, the pulse rate was recorded.
Results
The effect of Different Levels of Activity on Blood Pressure and Pulse Rate
The blood pressure values measured before and after activity were recorded in Table 1 below.
Effect of Body Posture on Blood Pressure
In the determination of the effect of different body posture on blood pressure, the results were recorded in Table 2 for the left arm and Table 3 for the right arm.
The Effect of Cognitive Activity and Sensory Inputs on Heart (pulse) Rate
The blood pressure and pulse rates during different cognitive activities and sensory inputs were determined and recorded in Table 4.
Discussion
The cardiovascular system refers to the transport system in the body that is involved in carrying oxygen and carbon dioxide as the respiratory gases, plasma proteins such as the hormones, hormones and other necessary material. The system is made up of the arteries, veins, the heart and other tissues. The artery is involved in taking blood from the heart to the other tissues while the veins are generally involved in taking the blood from the tissues back to the heart (Seeley, et al., 2004). Blood pressure is normally monitored by measuring the pressure of the blood in the arteries. The pressure is measured by determining the force with which the blood pushes against the walls of the arteries. The normal location for measuring blood pressure is the brachial artery (University of Aberdeen, 1999).
Blood pressure is one of the many variables that are closely regulated by the body system through osmoregulation. The control of the body pressure occurs through the use of several hormones. Those hormones that are involved in when the blood pressure is low are angiotensin II, aldesterone, adrenaline, noradrenaline, and antidiuretic hormone. The hormone produced when the blood pressure is high is the atrial natriuretic peptide (ANP) (SGUL, 2013). The heart work to pump blood to other body tissues to provide them with nutrient and oxygen while removing waste materials from those tissues. Increase in demand for the supply of nutrients and air requires an increase in blood supply and hence increases in heartbeat. Such an increase was noted in the subject used in the study with the blood pressure readings increasing from 116/74 before exercise to 176/124 after exercise.
Lying position with the arms at the level of the heart gave the lowest value for the left arm while lying position with the arm below the heart gave the lowest readings for the right arm and the highest for the left arm. For the left arm, the highest systolic readings were recorded while sitting with the arms at the same level with the heart while the highest pulse reading was recorded in a standing position immediately after lying. Handing the arm while sitting or standing is known to cause a reduction in blood pressure. Lying down has no effect on blood pressure as long as the arms are kept on the same level with the body. This is due to the fact that all the body parts are at the same level and there is no gravitational force reducing blood pressure.
The transition from lying to standing causes the blood to be pulled in the lower parts of the body due to the gravitational forces. This reduces the venous return which in turn reduces the volume of the blood getting into the heart. This reduces the arterial blood pressure. Such reductions require that the activation of the sympathetic activation to induce an increase in the heart rate and reduction of vascular resistance. Failure to activate sympathetic activity may lead to symptoms such as dizziness, fainting and blurred vision among others (Olufsen, et al., 2005).
In addition to posture, blood pressure is also affected by the cognitive activities with recalling stressful things increasing the blood pressure the highest. This may be due to the anxiety that results from such activity. Listening to music, as well as reciting timetable, caused no significant increase in blood pressure. This may be due to the low anxiety that is caused by these activities. Comparing the results for the different subjects, there is no significant difference among the subjects. All the subjects recorded a low baseline compared to the values recorded during the other cognitive activities. Some cognitive activities such as listening to music did not have any significant effect on the blood pressure. On the other hand, activities such recalling stressful moments result in a significant increase in blood pressure. The effect of these activities on the blood pressure is similar to their effect on the pulse rate.
In concussion, the experiment aimed to measure blood pressure and pulse and to understand the meaning of these readings. The experiment also aimed to identify why these factors may change in response to daily activities and how the body controls homeostasis with regard to blood pressure. From the results, posture, exercise, as well as cognitive activity, were shown to have an effect on the pulse rate and the level of blood pressure.
Reference List
American Heart Association, 2012. Understanding Blood Pressure Readings. [Online] Available at: http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/AboutHighBloodPressure/Understanding-Blood-Pressure-Readings_UCM_301764_Article.jsp[Accessed 3 March 2014].
NIH, 2012. What Causes High Blood Pressure?. [Online] Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/hbp/causes.html[Accessed 3 March 2014].
Olufsen, M. S. et al., 2005. Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation. Journal of Applied Physiology, 99(4), pp. 1523-1537.
Seeley, R., Stephens, T. D. & Tate, P., 2004. Anatomy and Physiology. 6th ed. New York: The McGraw Hill Companies.
SGUL, 2013. Hormonal Factors. [Online] Available at: http://www.elu.sgul.ac.uk/rehash/guest/scorm/214/package/content/[Accessed 3 March 2014].
WebMD, 2013. Understanding High Blood Pressure -- the Basics. [Online] Available at: http://www.webmd.com/hypertension-high-blood-pressure/guide/understanding-high-blood-pressure-basics[Accessed 3 March 2014].
