Research Design Example: A True Story of 3 Potatoes

How do you come up with your research design? Here are two examples of blood pressure exploratory studies as leads toward research design development.

Blood Pressure Exploratory Study

I find the practical aspects of applying research enjoyable and designed experiments to uncover some relationships or to resolve my problem.

Several years ago, I convinced my doctor to cut my blood pressure drug maintenance. I simply presented to him a graph I prepared using a spreadsheet application and an Analysis of Variance (ANOVA) to compare my blood pressure readings with the full dosage of the drug, half of it, and a fourth. I also compared the two groups at a time using t-test and I got the same results. The graph and the statistical analysis showed my blood pressure readings did not show a significant difference as I gradually reduced the dosage of the prescribed drug.

Research Design Example: The Diet Experiment

The primary purpose of the above experiment is to see whether diet can produce the same results as a drug in lowering blood pressure. One of the active components of the drug in question was potassium. I thought it is better to take natural food to get the mineral. I computed the amount of potassium that corresponds to the dosage by eating several potatoes that will supply such amount and gradually reduced the drug dosage while monitoring my blood pressure daily.

From my musings on the nutritional value of potato, it would take about two to three medium-sized potatoes to get the same amount of potassium. So, I took at least three potatoes a day to correspond to the amount of potassium required as I reduced on the drug dosage.

When I came around 1/4 of the prescribed dose, I asked the doctor if I can forego the drug because I suspect it is one reason I was feeling weak. And I confirmed it by finding information on the side effects of the drug. The doctor was amazed because I reduced the drug to such a small amount that, according to him, does not anymore provide substantial benefit in lowering blood pressure. My blood pressure has stabilized. He said I can forgo the drug and return to him when my blood pressure rises again.

Despite this apparent success in my desire to live without the drug in my system, I do not recommend this approach to anybody because it might work differently for different people. I take certain precautions when I conduct studies on myself.

Blood Pressure and Exercise Experiment

Recently, I’m at it again. This time, I just would like to verify if indeed exercise lowers blood pressure. My readings say so and I would like to personally find out what the numbers will show. I monitored by blood pressure before exercise, right after exercise and 15 minutes or more after my exercise so that my blood pressure will stabilize at rest.

I just started this last week and saw a trend just from three readings. I show the results of the blood pressure monitoring in the table below.

The results are interesting because obviously, my blood pressure went down right after exercise and dropped over 15 minutes after. Upon waking up, my blood pressure readings show that my systolic reading showing the maximum arterial pressure is higher than the normal 120mm Hg, but the systolic reading is normal. After exercise, the systolic pressure reduced just by visual inspection even while the heartbeat is high. After 15 minutes, the systolic and diastolic readings even went down further while my heartbeat approximates its normal value.

So are the results conclusive enough that exercise lowers blood pressure? There is no doubt exercise lowers blood pressure [1] but I have not seen details on how much blood pressure is reduced by exercise. This data informs me right away the benefits of exercise and serve as an encouragement to engage and maintain my exercise routine.

Today, when I went for my usual six kilometer run in 41 minutes and 38 seconds (the fastest so far in that distance), my blood pressure after exercise approximates the previous values. It is 104/65 with a heartbeat of 95. Again, after my heartbeat stabilized 15 minutes later at 64, while my corresponding blood pressure is 101/59.

Data Collection Procedure for the Exercise Experiment

How did I come up with such values? What is the data collection procedure? I collected this data systematically, making consistent readings as much as I can. Roughly, the data collection procedure goes this way and can be replicated by anybody.

I recorded data using the following data collection procedure:

Record BP and heartbeat –> stretching exercise for five minutes –> slow walk of 8 minutes –> run proper –> cooling down with a slow walk for about 15 minutes –> five-minute stretching –> record BP and heartbeat –> rest for 15 minutes –> record BP and heartbeat

I used an Omron Automatic Wrist Blood Pressure Monitor to make blood pressure readings. It read a little higher than the standard sphygmomanometer, but it reads consistently. So it will be easy to calibrate it for more standardized results.

From this exploratory study, which confirms the benefits of exercise in a quantitative way, we may develop a research design for more rigorous analysis. You should notice, however, that sleep may also have an influence on blood pressure readings, so I marked the third reading with an asterisk. The quality of my sleep in the first two readings is not that good as I only had six or fewer hours of sleep while on the third reading, I got a quality sleep of seven hours or more. This apparently resulted in lower blood pressure readings upon waking up.

This means that if I pursue this experiment, I should make my measurements consistent and consider the hours of sleep and factor it in for analysis. I should also make sure that monitoring time should be the same all throughout the duration of the study.

Now, the question is: “Are there studies conducted like this before?” I actually don’t know, as I am not a medical researcher. My experience is only a case study; a description of my case. But a review of literature will tell me if a similar experiment was done by anyone on a greater number of people. Different theories guide these experiments on the effects of exercise on blood pressure or general health developed through time. In my case, I just did it out of mere curiosity to verify my readings, which are also backed by theories.

From these initial data, we may develop an experimental research design to ensure that the evidence obtained answers the questions initially posed for the study. I posed two questions in these two examples: 1) Can a well-planned diet produce the same results as a drug in lowering blood pressure?, and 2) Does exercise lower blood pressure?

From simple case studies like these, we may design experiments to test if the findings are consistent for a greater number of people. This will also provide insights into which variables we should include for analysis.

Reference

1. Mayo Clinic (n.d.). Exercise: A drug-free approach to lowering high blood pressure. Retrieved August 27, 2013, from http://www.mayoclinic.com/health/high-blood-pressure/HI00024

© 2013 August 26 P. A. Regoniel | Updated 2023 January 10