Measuring the dependence between blood pressure and time

Materials:

• Sphygmomanometer
• Stethoscope
• Clock
• Pen and piece of paper

Procedure:

1. Conduct a brief inquiry about person’s gender, age and sport style (either passive or active)
2. Measure the person’s blood pressure:

1. The examined person has to sit comfortably with the hand resting on a table
2. Wrap the cuff around the upper arm of his/her left hand, about 2,5 cm above the elbow
3. Place the funnel of the stethoscope on the inner part of the elbow
4. Pump the air into the cuff and observe the blood pressure registered on a column of the sphygmomanometer
5. Carefully release the cuff pressure and wait
6. Listen for period of turbulent sounds of the heartbeats
7. Note down the results

Raw data:

Tab.3  Person’s gender, age and sport style and its systolic/diastolic blood pressure

Processed data:

 

Graph 1. The systolic blood pressure of people

Graph 2. The diastolic blood pressure of people

Tab.4 Mean systolic and diastolic blood pressure for person

The data from Tab. 4 compare the mean values of blood pressure between the people being objects of the experiment in search for any deviation.

Graph 3. Mean values of blood pressure between people

Tab.5 Mean systolic and diastolic blood pressure for hour

The data from Tab. 5 compare the mean values of blood pressure between the people being objects of the experiment in search for any deviation.

Graph 4. Mean systolic and diastolic blood pressure for hour (bar chart)

Graph 5. Mean systolic and diastolic blood pressure for hour (line chart)

Conclusions:

The extract below explains how blood pressure is regulated:

‘Blood arriving at the carotid bodies carrying a high concentration of carbon dioxide stimulates chemoreceptors in these regions to transmit impulses to the vasomotor centre. Nerve fibres leaving the chemoreceptors link with fibres from the carotid sinus by means of synapses before passing to the vasomotor centre. When the vasomotor centre is stimulated in this way it sends impulses to the blood vessels to vasoconstrict and therefore raises blood pressure. As increased carbon dioxide concentration in the body is usually brought about by increased activity by body tissues, the blood containing the carbon dioxide will be transported more rapidly to the lungs where removal of carbon dioxide in exchange for oxygen can take place more quickly’

The result of the experiment shows that the blood pressure is the highest in the morning and the afternoon, because of them being the most intense parts of the day. The lowest blood pressure was recorded in the night, the process of sleeping is the most soothing part of the day. It is worth noticing that also sport style is an important factor of the value of blood pressure.

Graph 1 and Graph 2 present that the middle-aged man have the highest both systolic and diastolic blood pressure. It is caused by the fact that male generally have stronger tendency to overweight than women, which is bad for artery system. Graph 3 additionally shows the differences between values of systolic and diastolic blood pressure of the individuals.

Graph 4 and Graph 5 evidently presents the changes of blood pressure throughout
the 48 hours. Graph 5 shows mean values of systolic and diastolic blood pressure with the highest and the lowest point outlined. Low blood pressure is caused by the relaxation during the sleep. The work of body and the brain is decreased, organism does not need as much oxygen as in the day, therefore the circulation of blood is slower.

The summit of blood pressure is reached at 8:00 AM, when the object was preparing for starting the day. Probably it was the growing level of stress caused by a hurry that led to increase of blood pressure.

Unfortunately many conditions which could influence the result were not considered, such as genotype, lifestyle or health habits. In addition the size of sample group was too small to fit more general research.

Evaluation:

Weaknesses:

1. Participants should be asked whether they take any drugs which reduce/increase their heartbeat
2. The activity of individuals during the experiment slightly different: they were going to sleep at different times, eating different portions of food etc. – that might have influenced the result

Limitations:

1. The sphygmomanometer I used was manual, less precise than automatic sphygmomanometer
2. In theory 4 people were measured at the same time, but it is impossible with only one sphygmomanometer and one person that takes the measurements. In the result, the time difference between the first and the last person measured can reach 10 minutes.
3. Some variables were outside control, e.g. amount of eaten food or stress before work

Possible improvements:

1. Each age group should consist of the greater number of women
2. Bigger sample group should be introduced in order to generalize the outcomes
3. A scale for stating whether someone has an active or passive sport style should be elaborated
4. The blood glucose level of each participant could be measured to show the overall physical condition and health of participants

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