We have come together to research and conduct an experiment, in order to find out if there is a correlation between blood pressure and exercise.
Therefore, this is the title of our project:
Is a person’s blood pressure before exercise related to his blood pressure after exercise?
First, here are the definitions of 2 terms that are used in our study:
- Pre-exercise Blood Pressure: Resting blood pressure that is taken prior to exercisng
- Post-exercise Blood Pressure: Blood pressure that is taken within 2 minutes after the completion of 40 jumping jacks.
Variables used in our study
- Independent Variable: Exercise (40 jumping jacks) - ratio variable
- Dependent Variable: Blood pressure (systolic and diastolic) - interval variable
Rationale behind our study
We hypothesize that exercising will result in different effects on the systolic and diastolic blood pressure of a person. Hence, we will be measuring the pre-exercise and post-exercise systolic as well as diastolic blood pressure, of our experimental subjects.
Systolic blood pressure is defined as the pressure that arises when the heart beats while pumping blood. Generally as work intensity increases, the systolic blood pressure in a person increases progressively as his/her cardiovascular system attempts to deliver more oxygen to the working muscles.
On the other hand, diastolic blood pressure is defined as the pressure that arises when the heart is at rest between beats. As blood vessels dilate and peripheral resistance decreases, little change in the diastolic blood pressure of a person is observed.
Therefore, a person's blood pressure is mostly determined by the overall resistance of the entire vascular system to flow.
During exercise, blood vessels relax in order to maximize flow to muscles that require more oxygen, while keeping blood flow brisk to other areas that are constantly in high demand of oxygen such as the brain. Simultaneously, blood vessels at areas where oxygen is less required constrict.
On the whole, our bodies make physiological adjustments to the blood vessels so as to balance the body's blood pressure with its physiological demands.
The sum total of all these physiological adjustments is usually either an overall decrease in systemic vascular resistance, or no increase at all. Thus, the diastolic blood pressure remains stable, or decreases slightly during exercise.
Hypotheses
Jumping jacks is a form of cardiovascular exercise; it is a full-body calisthenics exercise which will increase the heart rate, and therefore circulation of blood in the body. It is normally used as a warm-up and is done for only 1-2 minutes to increase a person's body temperature.
Hence, to ensure that participants jump for at least 1-2 minutes, we require them to do 40 jumping jacks, which we have tested to be be sufficient to result in minimum changes in a person's blood pressure.
- H0: There is no relationship between exercise and changes in blood pressure.
- H1: There is a relationship between exercise and changes in blood pressure.
METHODOLOGY
The experiment was conducted on
Thursday, 10 June 2010, from 11:00 to 12:00 outside H518.
School of Health Science, Nanyang Polytechnic.**(Before our group conducted the actual experiment on our test subjects, a pilot test was first conducted on ourselves)
Sampling
- Subjects in our study are chosen through simple random sampling
- A total of 30 subjects are required for our study
- Our sample group involves year 2 Occupational Therapy students between the ages of 18 to 25 years old
- A name list is first drawn up according to the class register
- Then, numbers are churned out through a random number generator found at http://stattrek.com/Tables/Random.aspx
- Students whose name matches the numbers generated above, are chosen to be our subjects.
Experiment
3 different stations were allocated to conduct our experiment.
Station A
- A subject is first asked to sit on a chair so his/her resting blood pressure (pre-exercise blood pressure) can be measured
- The cuff of the portable blood pressure machine is wrapped around the subject's right arm
- His/her resting (pre-exercise) systolic and diastolic blood pressure is measured and recorded in a chart
Station B
- The subject is asked to do 40 jumping jacks, 1 count of 4 each.
Station C
- After completing the jumping jacks, the subject is asked to sit down on a chair again.
- The cuff of the portable blood pressure machine is wrapped around his/her right arm, and his/her post-exercise blood pressure measured.
STASTICAL ANALYSIS AND RESULTS
Published below are screenshots of statistical analysis results from our SPSS:
1a. Data view for pre- and post-exercise systolic blood pressure
1b. Variable view for pre- and post-exercise systolic blood pressure
1c. Scatter plot for pre- and post-exercise systolic blood pressure
1d. Pearson's correlation coefficient
From the above table, a Pearson's correlation coefficient of 0.801 indicates a strong relationship between a person's systolic blood pressure before exercise, and his systolic blood pressure after exercise.
Therefore, there is a positive, strong and significant association between a person's systolic blood pressure before exercise and his systolic blood pressure after exercise.
1e. Linear regression
The linear equation is :
Post-exercise systolic blood pressure of participants = 1.015* (pre-exercise systolic blood pressure of participants) + 16.144
1f. Is the relationship the same for males and females?
1g. Pearson's Correlation Coefficient
There are positive, strong and significant associations between a person's systolic blood pressure before exercise and systolic blood pressure after exercise for females. The association for females is r=0.732, p=0.000, N=26.
As for the males, p=0.054>0.05, therefore the null hypothesis is not rejected, and thus there is no relationship between a person's systolic blood pressure before exercise and his systolic blood pressure after exercise for males.
2a. Data view for pre- and post- exercise diastolic blood pressure
2b. Variable view for pre- and post-exercise diastolic blood pressure
2c. Scatter plot for pre- and post-exercise diastolic blood pressure
2d. Pearson's correlation coefficient
From the above table, a Pearson's correlation coefficient of 0.619 indicates a moderately strong relationship between a person's diastolic blood pressure before exercise, and his diastolic blood pressure after exercise.
Therefore, there is a positive, moderate and significant association between a person's diastolic blood pressure before exercise and his diastolic blood pressure after exercise.
2e. Linear Regression
The linear equation is:
Post-exercise diastolic blood pressure of participants = 0.875* (pre-exercise diastolic blood pressure of participants)+12.881
2f. Is the relationship the same for males and females?
2g. Pearson's Correlation Coefficient
There is a positive, moderate and significant association between a person's diastolic blood pressure before exercise and his diastolic blood pressure after exercise for female. The association for females is r=0.563, p=0.003, N=26.
As for the male, p=0.063>0.05, therefore the null hypothesis is not rejected, and thus there is no relationship between a person's diastolic blood pressure before exercise and his diastolic blood pressure after exercise for males.
Discussi
on
Our experimental results for the changes in diastolic blood pressure, does not support what research has shown. This could be due to differences in the duration and intensity of the selected exercise. Also, our measurements could be affected by the time lapse between the end of the exercise and the measuring of blood pressure.
CONCLUSION
Our experiment has concluded that there is a relationship between exercise and changes in blood pressure.
REFLECTIONS
Shirleen:
I thought it was an interesting opportunity for us to put our theoretical knowledge into real practice by conducting an experiment on our own. Definitely a good prelude to our final year project! It was also really fun seeing our coursemates do jumping jacks for us, and it was a good problem solving opportunity once our data and statistical results were out.
Xiang Jun :
This statistics project engages us in hands-on data collection as a group. I feel that this project provides us with the opportunity to collect and generate new data, instead of relying on other people's research finding. It was also a fun and interesting way to learn about statistics through experiencing the whole process of data collection and analysis of data.
Alan:
I feel that this statistics project is very interesting. It allows us to apply what we have learned in lectures to good use. So this is no longer about theories, theories and theories! It about how to put theories into practice. Therefore it is very different from just studying and do not know what you are studying for.
Weizhen:
It was a great experience carrying out this project. It was interesting to see our friends and coursemates helping us to do the jumping jacks. Through this project, it had allowed us to learn about statistics in an interesting way. It gave us the opportunity to put what we had learnt into practice.
Suhailah:
I am glad that we were given the opportunity to carry out this project as it enables us to apply what we have learnt in lessons. This allowed me to remember and understand the theories better. On top of that, I think it is interesting to have our fellow coursemates as our subjects. It made this experience a fun one and at the same time a good preparation for our final year project!
REFERENCES
Bird, S. R., Smith, A., James, K. (1998). Exercise benefits and prescription. UK: Nelson Thornes Ltd.
McArdle, W. D., Katch, F. L., & Katch, V. L. (2009). Exercise physiology: nutrition, energy, and human performance. USA: Lippincott Williams & Wilkins.
McNeely, E., & Sandler, D. (2006). Power plyometrics: the complete plyometrics program. UK: Meyer & Meyer Verlag
Wilmore, J. H., & Costill, D. L. (1994). Physiology of sport and exercise 2nd edition. United States of America: Human Kinetics.
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