Let me just first state that I am not a medical doctor.  The experiments I have carried out on this site were carried out to satisfy my own curiosity, as I do have scientific training.  I do not recommend you try any of these yourself – consult your doctor if you have blood pressure problems.

My idea for these experiments was to look at various factors that have been reported as affecting blood pressure.  For those of us with hypertension (high blood pressure), this type of information if very important.

When I started these experiments, my own blood pressure was around 140/100.  Through carefully watching my diet, and increasing the level of exercise, my blood pressure dropped to normal levels.  In fact, its not unusual for my blood pressure to be now be around 100/60.

For all of these experiments, I used a home blood pressure monitor, with the upper arm cuff.  I did test the accuracy of this when I first started using it by comparing the readings with those taken by my doctor.

In this experiment, I wanted to see how exercise affected my blood pressure.

The experiment was simple.

I would do 7 minutes of weight training while seated (this involved shoulder presses).  Immediately afterwards I took my blood pressure twice, with three minutes in between.  I then did another 7 minutes of weights, but this time standing up (bicep curls).  After this 7 minutes I took my blood pressure immediately, and for several minutes afterwards.

Here are my results:

Here are my results in Graphical format:

Note that the arrows in the graph represent 7 minutes of exercise.

The immediate thing to notice is the obvious.  After exercise, my heart rate increases.  Heart rate increases to increase the flow of blood around the body so that increased oxygen uptake and increased release of carbon dioxide from the tissues can take place.

As for blood pressure, there are slight increases in both diastolic (lower) and systolic pressure (upper) pressures.  From rest, until the first measurement after the first 7 minutes of exercise, the systolic increase by 11 mmHg.  That represents a 9.8% increase in systolic pressure over the resting pressure.  The same measurement for diastolic shows the pressure going up 13 mmHg, representing an increase of 19.7% increase over the resting diastolic pressure.  It would therefore seem that in my case, both diastolic and systolic increase after exercise, though diastolic increase more.  Remember that the diastolic pressure is the pressure in my blood vessels BETWEEN heart beats, so my system is under higher pressure when at “rest”, after exercise.

12 minutes after exercise finished both blood pressure and heart rate was still elevated, so it appears that in my case at least, exercise did increase blood pressure, and that the increase lasted for some time after exercise finished, as did my elevated heart rate.

I used a filter coffee machine to prepare a large cup of coffee, made with decaffeinated ground coffee. The process was exactly the same as my experiment to see if caffeine coffee affected bloood pressure, except for the type of coffee, which in that case was obviously a standard caffeine coffee. In the current experiment, the coffee was decaf.

Here are my results:

Here is the data as a graph showing the effect of de-caffeine coffee on blood pressure:

Before drinking the coffee, my blood pressure was fairly stable at around 125/82. However, at 10:31, around 5 minutes after drinking the decaf coffee, my blood pressure fell to 116/78, and fell even further at 10:36 to 112/75.

For 10:31 to 10:50, my blood pressure was below the starting blood pressure of around 125/82. From 10:58 until the end of my experiment, blood pressure had returned to near the starting level.

It appears from these results that drinking the decaffeinated coffee reduced my blood pressure for a period of around 25 minutes before blood pressure returned to normal.

Now, whether this is due to the decaf coffee itself, or some other factor involved remains to be seen. For example, it may well be that the decaf coffee itself has no effect on blood pressure, and something like the heat in the drink was responsible.

As a follow up experiment, I need to drink an equivalent volume of hot water.

That will be my next experiment.

To prepare for each set of readings, I sat down for 5 minutes before taking the first reading.

The coffee used in this experiment was strong filtered coffee. After taking a few baseline readings, I drank the coffee in one go. The amount was equivalent to 4 small expresso coffees. I then continued to take my blood pressure every few minutes. I then sat as still as possible, taking my blood pressure every three minutes.

Here are my results:

Here is the data as a graph showing the effect of caffeine coffee on blood pressure:

You’ll see that there is an almost immediate increase in systolic pressure, followed by a drop. This then increases again about 10 minutes after drinking the coffee to a maximum measured blood pressure of 138/89 about 23 minutes after the coffee was drunk. The blood pressure then starts dropping again, until normal blood pressure is restored at around 30 minutes after drinking the coffee.

What we see happening is a temporary increase in blood pressure in response to the coffee, which the body then corrects. How caffeine raises blood pressure seems to be unclear, but what is certain in my case is that it did raise my blood pressure, but only for a short period of time.

For those with high blood pressure, it would appear that coffee could be a problem due to the high spike after drinking the coffee. However, since my blood pressure is normal, I wont be switching to decaf.

My next experiment is to see what effect drinking filtered decaffeinated coffee has. Is it the caffeine in the coffee that raised my blood pressure, or something else?  You can see the results of my experiment on the does decaffeinated coffee affect blood pressure page.  The results may surprise you!

To prepare for each set of readings, I got into position, and waited quietly for 5 minutes before taking the first reading.

I then took a minimum of 3 readings for each position, with 3 minutes between each reading. The results I show you below are the average of the readings for each position. I have also included heart rate for the three positions.

Blood pressure when lying down:

Blood Pressure Average: 115/70
Heart Rate: 66

Blood pressure when sitting down:

Blood Pressure Average: 120/79
Heart Rate: 72

Blood pressure when standing :

Blood Pressure Average: 121/78
Heart Rate: 75

As you can see, my blood pressure (and heart rate) was lowest when lying down. This is as expected, since the body is not having to work too hard to pump blood around the body, which is all pretty much in the same horizontal plane.

When the body then sits up, there is an increase in blood pressure and heart rate. Again, this is as I would have expected, since the body is now having to work a little harder to get the blood around the body.

Finally, when standing, there was no noticeable difference in my blood pressure from the sitting position. I had expected to possibly see a slight drop in blood pressure, though no change is not a big surprise. When you stand up, gravity causes blood to naturally wants to pool in your leg veins causing a drop in blood pressure. However, the autonomic nervous system tries to correct this by narrowing your blood vessels (which increases blood pressure) and increasing your heart rate. We did see the increased heart rate. The reason for no apparent drop in blood pressure is probably because the first reading was taken 5 minutes after standing. This would have given the body time to adjust.

Incidentally, I am not a doctor. These experiments are for my own curiosity, and I do not recommend you do the same.

Here are my results:

Here is the chart of this data:

While the graph may not look too impressive, you can see a large jump in blood pressure almost immediately. Before starting to smoke the cigar, the average blood pressure for the three preceding readings was 133/83. The first reading after starting to smoke was 149/92. That’s quite a jump.

The initial increase in blood pressure is spectacularly quick. Not surprising really, as smoke enters our bodies through the thin membranes of the lungs, as well as through the membranes in our mouth. This is why smokers can get a neat instant “hit” when they light up.

Blood pressure is raised for about 20 minutes before it returns back down to a more normal reading (that’s normal for me). When there is a stimulus to increase blood pressure, our bodies are going to try to combat that increase and lower the blood pressure. In this case it took about 20 minutes for my body to do so. Blood pressure then remained fairly constant for the remainder of the experiment.

It would be interesting to see how blood pressure would be affected if I continued to smoke all day (as in a chain smoker), and whether my body could compensate over a long period of time. I wont, however, be doing that experiment ;o)

Look out for new experiments soon. You’ll find them in the left hand menu.

The readings were not taken at specific intervals, and I have made no attempt to show on this graph when I ate food, did exercise, drank coffee, or anything else that might affect blood pressure. The whole point of this experiment was just to see how my blood pressure varied throughout the day.

Here are my results:

Average Blood pressure over the day: 129/82

Here is the chart of this data:

The fluctuations were not as big as I anticipated, but one thing I have noticed is that my blood pressure does tend to reduce as the evening progresses.

We have to be careful to draw any conclusions from this blood pressure data, but clearly, there is some variation during the day.

I will be looking at specific influences in other experiments, and how they affect my blood pressure, so look out for those. They will be listed down the left of this page.