Coffee and exercise reduces heart rate

[CianOConnor]

I have a Fitbit Versa 3 and it consistently tells me that coffee and some forms of exercise (especially cycling) cause my heart rate to decrease. While cycling my heart rate can drop as much as 15bpm vs the rate before I set off. And my resting heart rate on a day without coffee will be 3-5bpm higher than a day with 2 coffees.

Is this normal or could there be something wrong with the sensor?

[DavideFitbit · Accepted solution]

Hi, welcome to the Community forums, @CianOConnor.

 Thank you for sharing all this information about what you've been experiencing with your Versa 3 watch. 

It seems that things like coffee and the workouts you mentioned earlier should actually increase your heart rate and not decrease it. Before considering other options, I would recommend performing a restart and to follow all the instructions in this article to improve the accuracy of heart rate information, this has been useful to other users who have experienced something similar.  

Let me know if you see the same behavior with other type of workouts or while you're walking. 

I'll be around. 

[Heybales]

For the coffee effect - on days with no coffee are you still drinking as much fluids as the coffee would have provided?

For the cycling effect - do you mean you start out with say a certain intensity at 150 bpm, than later at what feels the same intensity (power meeter would be much more accurate than feeling) the HR is 135 bpm?

Warmup can easily explain some of that. As you get fitter that time for warmup shortens too.

How fit are you?

How long is the ride?

Does the HR start going up again the longer you ride, if the intensity is kept the same?

[CianOConnor]

For the coffee: yes I am drinking at least as much water.

For the cycling: the Fitbit could say my heart rate is 80-90bpm while sitting at my desk working. When I go out on the bike that will reduce to, say, 65. As a rule while on the bike, it says my heart rate is around 60 during high exertion (such as uphill sections) and increases to a more expected 120-140 when I stop to catch my breath afterwards.

[Heybales]

For the exercise - typical inaccurate reading then.

Take a manual pulse count and you'll easily confirm that.

One suggestion is push it farther up the arm until tight, hopefully catching some vessels it can read better.

Some people never find a solution - their arms are just bad reads when they go into exercise levels. It either stops at higher level, or drops out completely, or in your case maybe reading about 1/3 of the beats.

Other idea for the lack of coffee - slight withdrawal effect or stress from not having it.

[DavideFitbit]

Thank you for sharing those tips to improve accuracy, @Heybales! 😁