Effects of caffeine coffee on my blood pressure 4

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, after drinking a large cup of caffeine coffee.

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:

Upper (systolic)
Lower (diastolic)
09:43 119 80
09:46 116 81
09:49 118 80
09:52 126 77
09:55 117 77
09:58 110 76
10:01 112 78
10:04 119 83
10:07 125 80
10:10 134 78
10:13 138 89
10:16 114 74
10:19 120 76
10:22 120 76
10:25 115 76
10:28 117 77

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!

Want to Buy a Blood Pressure Monitor?

I recommend you get an upper arm monitor rather than the wrist variety, as my own testing shows them to be more accurate.   The model I recommend is this one:

omron blood pressure monitor cuff

Omron Cuff Blood Pressure Monitor on Amazon

About Andy

Andy writes for a number of health related sites but has always been fascinated by alternative medicine and home remedies. His deep interests in nature and the body's innate ability to heal itself (given the right condition) have lead him to a pivotal time in his life - and so, Holistic Home Fitness was born. While it's relatively new at the moment, Andy wants to build this site into a huge reference site for a more holistic approach to health and fitness.

4 thoughts on “Effects of caffeine coffee on my blood pressure

  • Angel

    I feel that they should make coffee with out as much cafine as it usually is because now days kids at 5 to 9 are drinking coffee and it could really have a bad effect on there heart rate and blood presure because of there ge and how small their insides are.

  • john

    yesterday i was feeling very weird and my head was going thru some fainty feelings all morning. i had someone take my bp and it was 150/110. i wonder if this was because i drank four cups of coffee that morning?

    • Peter

      I agree it could be Hawthorne Effect. Andy should really have someone give him a pill which is either contains a cups-worth of caffeine or no caffeine and then measure it.

      Also, it can take up to 45 mins to metabolize caffeine so I would be cool to see BP measurements over the whole day, since caffeine obviously has an effect into the evening (for me at least).


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