Effects of decaffeinated coffee on my blood pressure

In these experiments, I used an upper arm cuff home blood pressure monitor to measure my blood pressure on an empty stomach, after drinking a large cup of decaffeine coffee.

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.

Effect of lying down, sitting, and standing on blood pressure.

In these experiments, I used a home blood pressure monitor (upper arm cuff), to measure my blood pressure in the morning, on an empty stomach.

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.

Blood pressure variations during the day

In this first of many blood pressure experiments, I used a home blood pressure monitor (upper arm cuff), to measure my blood pressure during my waking day.

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.

Recommended Reading

Further Reading

The following books are related to high blood pressure and offer more information on this topic.

HELLP Syndrome

What is HELLP Syndrome? HELLP Syndrome is a rare, but serious complication that occurs in up to 12 percent of the women who have preeclampsia.

The syndrome is named after the main characteristics of the disease, namely Hemolysis (break down of red blood cells), Elevated Liver enzymes, which can cause liver damage, and Low Platelet count (platelets are involved in blood clotting).

What are the symptoms of HELLP Syndrome?

Symptoms include:

• a gradual onset of headaches
• weakness & fatigue
• blurred vision
• nausea & vomiting
• pain around the upper abdomen
• jaundice
• diarrhea
• tingling in the extremities

One of the problems in diagnosing HELLP, is that not every woman exhibits all of these symptoms, so any woman showing a mixture of symptoms, should be evaluated for HELLP. Unfortunately, HELLP syndrome is often disdiagnosed in the early stages, increasing the risks of liver failure and death. If you are pregnant, and suffering from any of the above symptoms, please consult your doctor as soon as possible.

How is HELLP Syndrome Diagnosed?

Diagnosing HELLP syndrome may include:

• Full physical examination
• blood pressure measurement
• red blood cell count
• bilirubin level
• liver function tests
• platelet count
• urine tests for protein

Platelet counts are considered good indicators of HELLP severity (the Mississippi classification system). Class I is the most severe, with less than 50 million/l Class II is between 50 – 100 million/l Class III is greater than 100 million/l

How is HELLP Syndrome Treated?

Some medications have been looked at for treating HELLP, but the results of tests are inconclusive. Those treatments include:

• Magnesium sulphate which is throught to reduce the risk of seizures and slow the progress of eclampsia.
• fresh frozen plasma
• blood transfusion to treat anaemia.
• In mild cases, corticosteroids and antihypertensives may be sufficient.
• Intravenous fluids.

Cesarean delivery of the baby is the only effective treatment, even if it the baby is premature. The decision is usually made early because of deteriorating health (and liver function) of the mother becomes a threat to both moth and baby.

Complications of HELLP syndrome

Failure to effectively treat HELLP can lead to liver damage, and even death. Please consult your doctor if you have any of the symptoms listed above.